I’m sure that many people yearn for the glamorous life of the food microbiologist leading the war against microorganisms - yeah, right! Perhaps those people visualise the microbiologist surrounded by modern laboratory equipment, such as PCR machines and gene sequencers, but the sad fact is that what is portrayed in films and television just isn’t reality. It might be the case in forensic work or pathogen testing, but in the food industry, much of the work involves monotonous sampling and plate counting.
This is because there is a constant battle between food manufacturers and the microorganisms that can cause spoilage or food poisoning. Food safety is assessed in relation to counts of specific bacteria, yeasts and moulds. The International Commission on Specifications for Foods was formed in 1962 and wrote Microbiology of Foods Volume 2: Food Commodities in 1980. This was updated in 1996 (1). Our Microbiological Reference Criteria for Food were published by the Ministry of Health and Version 2 appeared in 1995. The Reference Criteria are expressed in the ICMSF format as a guide to indicate when food can be considered unacceptable or unsafe.
The result is that many food microbiologists and technicians spend a large part of their working day conducting plate counts on foods. This is particularly so in the dairy industry, though large laboratories such as these may use automation for plating, such as spiral platers, robotic sample diluters, and image analysis for counting. This is, of course, very expensive and involves a lot of plastic that probably cannot be recycled. Modern devices, such as the flow cytometer - a machine that counts particular cell types flowing through a tube by reflection of laser beams, reduces the usage of disposable plastics. Against this background, it is disappointing that food-borne infections continue unabated in the USA, UK and Europe.
Of course, some food microbiologists do lead an interesting life. These are the Special Agents investigating food contamination, poisoning and spoilage. While it might be argued that there is nothing new under the Sun, each case is different - human error, mechanical breakdown, packaging failures and poor equipment design may all figure in the systematic examination, leading to an understanding of what has gone wrong and a suggested solution. Investigation often involves looking closely at the process and interviewing operators. Access to a suitable microbiological testing laboratory is often essential in identifying the problem.
Looking back over many years as a consultant microbiologist, I can think of lots of investigations where the explanation was a surprise:
A dried vegetable processing operation in which the product had spikes of contamination. On this occasion, I was fortunate to see the problem immediately. The vegetables passed through a steam blancher which was located under a cold air trunking. Steam condensed on the trunking, which was covered in a thick black tarry layer, and every so often, condensate would fall onto the vegetables being conveyed to the drier. A factory design fault.
Staphylococcus aureus contamination of canned product. This was not a low acid food and therefore was not subject to a 12-D process. The immediate suggestion was that the cans were leaking during cooling, sucking in cooling water. However, it was found that the cans were dump loaded into a lidded vessel and hot water was introduced and held for the duration of the process schedule. With a temperature above 75oC for a suitable time, the Staphylococci should have been destroyed. We eventually discovered that the vessel was overloaded and some of the cans were above the water level, so did not receive the scheduled process.
In a small pie shop, minced meat for pie filling was cooked on a stove in large pans of about 35 L capacity, which were then put into a chiller to cool. On occasion, the pies spoiled after the growth of Clostridial spores activated by the heating. I found that the pans of meat took over 48 hours for the centre to cool to about 12oC. The solution was simple - put the filling into shallow trays for cooling.
Listeria monocytogenes was found in sliced meat. The slicer was a standard design, but was very difficult to clean properly and dried meat residue was found in the transfer mechanism. The slicer was mounted on a stainless steel table, and the whole area was meticulously cleaned. However, the table surface was heavily scratched and two feet mounting spikes penetrated the stainless steel. Unfortunately, the stainless steel was only a couple of millimetres thick and was laid on Medium Density Fibreboard (MDF). The result was that the MDF got wet every time the table was cleaned and became colonised by L. monocytogenes.
These examples show that those working in processing facilities may be essentially blind to potential failures and a fresh set of eyes with appropriate experience may recognise the problems quickly.
References
1. ICMSF. (1996) Microoganisms in Foods 6: Microbial Ecology of Food Commodities.
2. Ministry of Health (1995) Food Administration Manual S. 11: Microbiological Criteria
Showing posts with label contamination. Show all posts
Showing posts with label contamination. Show all posts
Wednesday, July 30, 2025
Germ Warfare
Thursday, December 27, 2018
McDonald's screen of death. I remain unsurprised.
A recent post from IFLScience.com claims that microbiologists from London Metropolitan University conducted swabbing on touch screens in McDonald's restaurants in London and Birmingham, finding coliforms, Bacillus and Listeria. They also found Staphylococcus, Pseudomonas, Enterococcus faecalis and Klebsiella.
All of these bacteria are capably of causing infections, and you will find some discussion of these bacteria on this blog site - see labels.
But should we be surprised and should customers at McDonald's be concerned? Well, I am not at all suprised. If a microbiologist conducts swabbing in any public place, such as a supermarket, they will find all of these bacteria, perhaps on trolley handles, push plates on doors, in the toilets etc. As for the customers, if they are concerned, they could order their meal on the touch screen, then wash their hands, or use a hand sanitiser. Be honest - if you go to any fast food joint after you have been shopping in the mall, do you always wash your hands before you eat?
The original research was done for Metro (see https://metro.co.uk/2018/11/28/poo-found-on-every-mcdonalds-touchscreen-tested-8178486/). Not surprisingly, when this post was published on FaceBook, there were 1.2 thousand comments and nearly a thousand shares. My personal opinion is that this article was written and published for shock value and to boost circulation. Interestingly, a video clip posted on this same site showed that the majority of customers were not surprised by the findings and would still go and purchase food there.
Whatever you think of McDonald's or any other fast food outlet, in my opinion, the researchers are making a mountain out of a molehill, and IFLScience is making it worse. Don't pick on just one fast food chain, and think about how you protect yourself and your family from infection.
And while you are at it, think about a similar scenario in your own home.
Food for thought: How do you recognise the microbiologists around you? They are the people who use their little fingers or elbows to open doors, use a paper towel to turn the taps off in a public washbasin, use a knuckle on the touch screen and who often use hand sanitiser before eating in public.
All of these bacteria are capably of causing infections, and you will find some discussion of these bacteria on this blog site - see labels.
But should we be surprised and should customers at McDonald's be concerned? Well, I am not at all suprised. If a microbiologist conducts swabbing in any public place, such as a supermarket, they will find all of these bacteria, perhaps on trolley handles, push plates on doors, in the toilets etc. As for the customers, if they are concerned, they could order their meal on the touch screen, then wash their hands, or use a hand sanitiser. Be honest - if you go to any fast food joint after you have been shopping in the mall, do you always wash your hands before you eat?
The original research was done for Metro (see https://metro.co.uk/2018/11/28/poo-found-on-every-mcdonalds-touchscreen-tested-8178486/). Not surprisingly, when this post was published on FaceBook, there were 1.2 thousand comments and nearly a thousand shares. My personal opinion is that this article was written and published for shock value and to boost circulation. Interestingly, a video clip posted on this same site showed that the majority of customers were not surprised by the findings and would still go and purchase food there.
Whatever you think of McDonald's or any other fast food outlet, in my opinion, the researchers are making a mountain out of a molehill, and IFLScience is making it worse. Don't pick on just one fast food chain, and think about how you protect yourself and your family from infection.
And while you are at it, think about a similar scenario in your own home.
Food for thought: How do you recognise the microbiologists around you? They are the people who use their little fingers or elbows to open doors, use a paper towel to turn the taps off in a public washbasin, use a knuckle on the touch screen and who often use hand sanitiser before eating in public.
Wednesday, August 1, 2018
I've been served some pretty awfull coffee in my time ...
Many people on Twitter are reporting that a pregnant woman in Alberta ordered a latte at a McDonald's but was served a cup containing cleaning fluid.
According to a report on CBC News, this was caused by the coffee machine still being connected to two cleaning solution supply lines, rather than the milk reservoir. The cleaning chemical was a mixture of citric acid, phosphoric acid, methyl-trimethyl-3, and 2-butoxyethanol. There is no doubt that ingestion of this material would be harmful.
It's not clear whether the cup contained hot liquid, though if the machine were set to deliver coffee, but connected to a cleaning chemical supply, it's likely that the cup did feel normal, and since it was a takeaway, it would have been fitted with a lid, so gave no indication that it didn't contain latte.
This potentially very dangerous incident gives a lesson: if you are a pilot, a car driver, or the operator of a food processing machine, the principles are pretty much the same - the pre-start checks must always be conducted before any start and done properly.
According to a report on CBC News, this was caused by the coffee machine still being connected to two cleaning solution supply lines, rather than the milk reservoir. The cleaning chemical was a mixture of citric acid, phosphoric acid, methyl-trimethyl-3, and 2-butoxyethanol. There is no doubt that ingestion of this material would be harmful.
It's not clear whether the cup contained hot liquid, though if the machine were set to deliver coffee, but connected to a cleaning chemical supply, it's likely that the cup did feel normal, and since it was a takeaway, it would have been fitted with a lid, so gave no indication that it didn't contain latte.
This potentially very dangerous incident gives a lesson: if you are a pilot, a car driver, or the operator of a food processing machine, the principles are pretty much the same - the pre-start checks must always be conducted before any start and done properly.
Sunday, January 7, 2018
Raw water: Is it bullshit?
There is a new fad spreading rapidly in the US. "Raw water" is the latest craze for health fanatics keen to spend serious money.
What is raw water? Its proponents claim it is water as nature intended it - unfiltered and untreated, containing minerals from the water source and no chlorine. One raw water company claims that "all other bottled, filtered, tap, and even spring waters are sterilised with ozone gas, irradiated with UV light, and passed through a submicron filter" and that "blasting water with ozone changes its molecular structure". Clearly, there is some truth in this statement, but also a lot of nonsense.
Some water sources are indeed safe to consume untreated; others may appear to be so, but are not safe. In August 2016, over 1000 residents of Havelock North in New Zealand became ill after consuming drinking water from two bores operated by the local council. Investigations showed that the affected residents had been infected by Campylobacter. This was not the first time that the bore heads had been found to be contaminated. The outcome of an extensive investigation was that the water in the bore heads was contaminated with water from an adjoining farm pond on land that had been inundated by heavy rains. The aquifer was not contained and when the pumps were turned on, water from the pond, probably contaminated with sheep faeces, was drawn into the town supply. Anecdotal evidence says that the level in the pond dropped when the pumps were turned on. An immediate response was to chlorinate all water supplied in the area, which annoyed some residents, and the two affected bores were closed. Water was drawn from other bores in the nearby Hastings area and the supply has been chlorinated.
I am constantly surprised by people who want to turn back the clock to a time when food and water borne diseases were common, before modern scientific and technological advances made our lives much safer. Campaigning to ban chlorination of town water is one of those issues. Consumption of raw milk is another one of those desires that can lead to illness.
However, I am also reminded constantly that many rural areas are not serviced by mains water and wastes are treated on site in septic tanks, then discharged to the land. Our house on our own lifestyle farm collects water from the roof and stores it in 36,000L tanks. There is no filtration, chemical or UV treatment. We, like many other rural dwellers, are thereby deliberately exposing ourselves to risk, though there is no alternative other than boiling water or buying bottled water for drinking. The only thing I can say is that since moving to the farm over 30 years ago, we have never suffered from gastrointestinal illness.
Where does this leave us? Treated tap water is probably the safest water supply. Experience shows that rural tank water is usually safe, though it is not sterile; provided that the tanks are protected from contamination by animals or from septic tanks, there is little to fear from drinking it. The perceived benefits of bottled raw water may be illusory, and the marketing hype criticising filtration and ultraviolet treatment of spring waters is just plain misleading. Those getting the most benefit from bottled raw water are the suppliers.
What is raw water? Its proponents claim it is water as nature intended it - unfiltered and untreated, containing minerals from the water source and no chlorine. One raw water company claims that "all other bottled, filtered, tap, and even spring waters are sterilised with ozone gas, irradiated with UV light, and passed through a submicron filter" and that "blasting water with ozone changes its molecular structure". Clearly, there is some truth in this statement, but also a lot of nonsense.
Some water sources are indeed safe to consume untreated; others may appear to be so, but are not safe. In August 2016, over 1000 residents of Havelock North in New Zealand became ill after consuming drinking water from two bores operated by the local council. Investigations showed that the affected residents had been infected by Campylobacter. This was not the first time that the bore heads had been found to be contaminated. The outcome of an extensive investigation was that the water in the bore heads was contaminated with water from an adjoining farm pond on land that had been inundated by heavy rains. The aquifer was not contained and when the pumps were turned on, water from the pond, probably contaminated with sheep faeces, was drawn into the town supply. Anecdotal evidence says that the level in the pond dropped when the pumps were turned on. An immediate response was to chlorinate all water supplied in the area, which annoyed some residents, and the two affected bores were closed. Water was drawn from other bores in the nearby Hastings area and the supply has been chlorinated.
I am constantly surprised by people who want to turn back the clock to a time when food and water borne diseases were common, before modern scientific and technological advances made our lives much safer. Campaigning to ban chlorination of town water is one of those issues. Consumption of raw milk is another one of those desires that can lead to illness.
However, I am also reminded constantly that many rural areas are not serviced by mains water and wastes are treated on site in septic tanks, then discharged to the land. Our house on our own lifestyle farm collects water from the roof and stores it in 36,000L tanks. There is no filtration, chemical or UV treatment. We, like many other rural dwellers, are thereby deliberately exposing ourselves to risk, though there is no alternative other than boiling water or buying bottled water for drinking. The only thing I can say is that since moving to the farm over 30 years ago, we have never suffered from gastrointestinal illness.
Where does this leave us? Treated tap water is probably the safest water supply. Experience shows that rural tank water is usually safe, though it is not sterile; provided that the tanks are protected from contamination by animals or from septic tanks, there is little to fear from drinking it. The perceived benefits of bottled raw water may be illusory, and the marketing hype criticising filtration and ultraviolet treatment of spring waters is just plain misleading. Those getting the most benefit from bottled raw water are the suppliers.
Friday, June 9, 2017
Hand washing is REALLY important
According to a post on Stuff, a worker at a Silver Fern Farms meat plant in New Zealand lost her job for not washing her hands.
At first sight, this may appear to be a draconian decision, but the company had written procedures in place, stating that if a worker touched dropped meat, they should wash their hands before handling other meat being prepared for packaging. Meat that has fallen onto the floor can be contaminated by many different bacteria and by other organic material. Handling this fallen meat and the area around the dropped meat table could contaminate the worker's hands and hence other meat being packaged.
If the worker had been properly inducted into the plant, she would have been made aware of the requirement to wash hands after retrieving meat from the floor and transferring it to the dropped meat table.
The real problem is that the company has a meat export licence that almost certainly has stringent hygiene requirements incorporated. Thus failing to observe the written procedures in relation to dropped meat could have put the licence, and the livelihoods of all other workers at the plant, at risk.
At first sight, this may appear to be a draconian decision, but the company had written procedures in place, stating that if a worker touched dropped meat, they should wash their hands before handling other meat being prepared for packaging. Meat that has fallen onto the floor can be contaminated by many different bacteria and by other organic material. Handling this fallen meat and the area around the dropped meat table could contaminate the worker's hands and hence other meat being packaged.
If the worker had been properly inducted into the plant, she would have been made aware of the requirement to wash hands after retrieving meat from the floor and transferring it to the dropped meat table.
The real problem is that the company has a meat export licence that almost certainly has stringent hygiene requirements incorporated. Thus failing to observe the written procedures in relation to dropped meat could have put the licence, and the livelihoods of all other workers at the plant, at risk.
Tuesday, June 4, 2013
Third World water supply
Residents of this village have been boiling their water for drinking for the past four years. They have just been told that they can expect to do this for at least another ten years, because upgrading the supply is not a priority.
The village water supply, which is drawn from an open stream, was described by the regional mayor as "Potentially safe to drink, most of the time". There is the possibility of Giardia and Cryptosporidium contamination in the water supply. Doesn't sound too good does it?
The UN General Assembly declared on 28th July 2010 that safe and clean drinking water and sanitation is a human right essential to the full enjoyment of life and all other human rights. The General Assembly also voiced deep concern that almost 900 million people worldwide do not have access to clean water.
So, is this village in Africa, South America, or India? No. It's in the North Island of New Zealand. That puts these residents on a par with many Third World countries.
Mathew Grocot, writing in the Manawatu Standard this week, reports that the Horowhenua District Mayor told the local residents association that the minimum period before residents could expect to see a tangible improvement in their water supply was ten years. Water and sewage projects in the district would cost more than $100 million over the next 20 years. Another town in the district had priority for upgrade of its water and sewage systems.
Some residents were predictably annoyed when told that other infrastructure projects, including a community centre, library and park upgrades in other towns had priority. When asked why these projects were deemed more important than the village water supply, the mayor said that if these community facilities were not provided, people would not want to live in the district.
Seems to me that crap in the water is a really good reason not to live there.
The village water supply, which is drawn from an open stream, was described by the regional mayor as "Potentially safe to drink, most of the time". There is the possibility of Giardia and Cryptosporidium contamination in the water supply. Doesn't sound too good does it?
The UN General Assembly declared on 28th July 2010 that safe and clean drinking water and sanitation is a human right essential to the full enjoyment of life and all other human rights. The General Assembly also voiced deep concern that almost 900 million people worldwide do not have access to clean water.
So, is this village in Africa, South America, or India? No. It's in the North Island of New Zealand. That puts these residents on a par with many Third World countries.
Mathew Grocot, writing in the Manawatu Standard this week, reports that the Horowhenua District Mayor told the local residents association that the minimum period before residents could expect to see a tangible improvement in their water supply was ten years. Water and sewage projects in the district would cost more than $100 million over the next 20 years. Another town in the district had priority for upgrade of its water and sewage systems.
Some residents were predictably annoyed when told that other infrastructure projects, including a community centre, library and park upgrades in other towns had priority. When asked why these projects were deemed more important than the village water supply, the mayor said that if these community facilities were not provided, people would not want to live in the district.
Seems to me that crap in the water is a really good reason not to live there.
Monday, January 7, 2013
Fancy a snot pie?
The thought of this is totally gross. Why would I contemplate writing under such a heading?
Unfortunately, it's quite possible that some customers have in fact been sold pies contaminated by the profuse nasal secretions of a baby held in the arms of the cook filling the pies. Talia Shadwell wrote a piece in the Manawatu Standard at the end of December 2012 about a family-owned Rangitikei food premises forced to close because of a very unfavourable food safety inspection report. In addition to the highly probable contamination of the pies by the infant, the milkshake blender was encrusted with rotten milk. It is likely that there were other violations of good catering practice and the Food Hygiene Regulations.
Legislation is changing in New Zealand, but it is safe to say that the intent of the regulations will not change. District councils are responsible for registering food premises and it is illegal to sell food not produced in registered premises.
"No persons shall be issued with a Certificate of Registration for food premises (except a vehicle used solely for the carriage or delivery of food for sale) unless -
Unfortunately, this state of affairs is probably more common than we would like to think - many food premises are run by immigrants who provide the rich diversity of foods available in New Zealand, but who may have very limited knowledge of the language and regulations. This is no excuse for poor hygiene and food production practices.
Consumers have a right to expect their food to be safe to consume and to be produced under aesthetically acceptable conditions.
Unfortunately, it's quite possible that some customers have in fact been sold pies contaminated by the profuse nasal secretions of a baby held in the arms of the cook filling the pies. Talia Shadwell wrote a piece in the Manawatu Standard at the end of December 2012 about a family-owned Rangitikei food premises forced to close because of a very unfavourable food safety inspection report. In addition to the highly probable contamination of the pies by the infant, the milkshake blender was encrusted with rotten milk. It is likely that there were other violations of good catering practice and the Food Hygiene Regulations.
Legislation is changing in New Zealand, but it is safe to say that the intent of the regulations will not change. District councils are responsible for registering food premises and it is illegal to sell food not produced in registered premises.
"No persons shall be issued with a Certificate of Registration for food premises (except a vehicle used solely for the carriage or delivery of food for sale) unless -
• That person has been issued with a Council recognised Certificate in Food Hygiene or another qualification approved by Council; orIt is perhaps surprising that the inspection report noted that the family had 'very limited' knowledge of food hygiene and food safety practices.
• There is, working on the food premises, a Manager or a staff member with specific responsibility for staff training in food hygiene, who has been issued with a Certificate in Food Hygiene, a Certificate in Basic Food Hygiene or other qualification approved by Council."
Unfortunately, this state of affairs is probably more common than we would like to think - many food premises are run by immigrants who provide the rich diversity of foods available in New Zealand, but who may have very limited knowledge of the language and regulations. This is no excuse for poor hygiene and food production practices.
Consumers have a right to expect their food to be safe to consume and to be produced under aesthetically acceptable conditions.
Monday, June 4, 2012
Safe Food in Troubled Times
On 4th September, 2010, Christchurch was violently shaken by a Magnitude 7.1 earthquake. On 22nd February 2011, an M 6.1 shock destroyed much of the city centre and since that time, there have been about 3400 shocks of greater than M 3.
After the February earthquake, I expected to read of food and water related diseases spreading through the population - the water supplies were seriously damaged and sewer pipes were destroyed, while liquefaction of the ground allowed mixing of ground water and sewage to occur. Contamination of water supplies by faecal bacteria and viruses was therefore a serious consideration. People handling food for themselves and others would have to take great care with personal hygiene and cleaning of food preparation areas.
Amazingly, there were no major disease outbreaks.
New Zealand sits on the Pacific Ring of Fire and is sometimes called The Shaky Isles. We are taught to look after ourselves during a shake and to make preparations to look after ourselves in the aftermath. In my rumpus room out back, I have a cache of canned food and bottled water. But how many of us expected the Christchurch earthquakes to go on for so long? My cache would last for only a couple of days. Some people in badly damaged areas had to cook in their gardens on barbeques and open fires for many days.
This set me thinking about security of food supplies after such disasters. I guess that natural disasters are one thing; what must it be like when those waging civil war deliberately set out to destroy infrastructure?
We can expect that help might take a few days to arrive. Local emergency services will be overwhelmed by the number of people requiring assistance and their own degraded response capabilities - roads will be damaged and may be impassable for emergency vehicles. Stores and warehouses may be destroyed, power supplies will be interrupted and food may therefore be scarce, spoiled and possibly contaminated.
The first few days are therefore critical for the population to survive and begin rebuilding their lives. A secure and safe supply of food and water is essential. How does the average family prepare for their own and their neighbours' welfare? Dried and canned foods provide a safe and stable basis for the emergency supply.
There are many websites that will help you plan. Civil Defence in New Zealand provides lots of valuable information, such as lists of things you need in a survival kit; commercial organisations offer ready-made kits and meals that can be prepared with minimal resources.
I don't endorse the following sites or products, but you may find them useful.
A quick search on one of the major search engines will provide you with many more links to valuable information.
If you want more information on the Christchurch earthquakes, see the following:
After the February earthquake, I expected to read of food and water related diseases spreading through the population - the water supplies were seriously damaged and sewer pipes were destroyed, while liquefaction of the ground allowed mixing of ground water and sewage to occur. Contamination of water supplies by faecal bacteria and viruses was therefore a serious consideration. People handling food for themselves and others would have to take great care with personal hygiene and cleaning of food preparation areas.
Amazingly, there were no major disease outbreaks.
New Zealand sits on the Pacific Ring of Fire and is sometimes called The Shaky Isles. We are taught to look after ourselves during a shake and to make preparations to look after ourselves in the aftermath. In my rumpus room out back, I have a cache of canned food and bottled water. But how many of us expected the Christchurch earthquakes to go on for so long? My cache would last for only a couple of days. Some people in badly damaged areas had to cook in their gardens on barbeques and open fires for many days.
This set me thinking about security of food supplies after such disasters. I guess that natural disasters are one thing; what must it be like when those waging civil war deliberately set out to destroy infrastructure?
We can expect that help might take a few days to arrive. Local emergency services will be overwhelmed by the number of people requiring assistance and their own degraded response capabilities - roads will be damaged and may be impassable for emergency vehicles. Stores and warehouses may be destroyed, power supplies will be interrupted and food may therefore be scarce, spoiled and possibly contaminated.
The first few days are therefore critical for the population to survive and begin rebuilding their lives. A secure and safe supply of food and water is essential. How does the average family prepare for their own and their neighbours' welfare? Dried and canned foods provide a safe and stable basis for the emergency supply.
There are many websites that will help you plan. Civil Defence in New Zealand provides lots of valuable information, such as lists of things you need in a survival kit; commercial organisations offer ready-made kits and meals that can be prepared with minimal resources.
I don't endorse the following sites or products, but you may find them useful.
http://www.pcc.govt.nz/A-Z-Services/Emergency-Management/It-s-Easy---Get-prepared/Emergency-Food-Stores
http://www.prepare.co.nz/default.asp?c=11655
http://www.efoodsdirect.com/
http://whatscookingamerica.net/LeaSchneider/EmergencyFoodPantry.htm
http://www.bt.cdc.gov/preparedness/kit/food/
A quick search on one of the major search engines will provide you with many more links to valuable information.
If you want more information on the Christchurch earthquakes, see the following:
http://www.christchurchquakemap.co.nz/
http://www.geonet.org.nz/var/storage/images/media/images/earthquake/aftershock_decay/58870-7-eng-GB/aftershock_decay.png
Wednesday, August 24, 2011
Natural mercury in fish
Most of the posts on this blog are about bacterial food poisoning, so this post is a change on two counts.
Mercury contamination of fish is usually associated with industrial pollution of rivers and estuaries. William Ray, of Radio New Zealand, today reported that experts have suggested that the levels of mercury in trout in waterways around Totorua are so high, people should limit their intake to one trout per month. (I wish I could catch so many!).
Rotorua is one of New Zealand's most famous geothermal areas and the experts have suggested that the mercury is from natural hydrothermal sources. However, it appears that runoff from farms in the area may also be involved. The nutrients washed into the rivers and lakes cause algal blooms, which lower the dissolved oxygen content of the water. This in turn allows transfer of mercury from mud into the water, from whence it enters the food chain.
Perhaps the most infamous mercury poisoning occurred in the Japanese city of Minamata, which gave the name Chisso-Minamata disease to the resulting neurological syndrome. The Chisso Corporation chemical factory released methyl mercury into the Minamata Bay and this highly toxic compound was accumulated by fish and shellfish.
The Rotorua trout have also accumulated mercury, but Dr. Ngaire Phillips from the National Institute of Water and Atmospheric Research points out that the recommendation for consumption of no more than one trout per month is based on a lifetime consumption.
Mercury contamination of fish is usually associated with industrial pollution of rivers and estuaries. William Ray, of Radio New Zealand, today reported that experts have suggested that the levels of mercury in trout in waterways around Totorua are so high, people should limit their intake to one trout per month. (I wish I could catch so many!).
Rotorua is one of New Zealand's most famous geothermal areas and the experts have suggested that the mercury is from natural hydrothermal sources. However, it appears that runoff from farms in the area may also be involved. The nutrients washed into the rivers and lakes cause algal blooms, which lower the dissolved oxygen content of the water. This in turn allows transfer of mercury from mud into the water, from whence it enters the food chain.
Perhaps the most infamous mercury poisoning occurred in the Japanese city of Minamata, which gave the name Chisso-Minamata disease to the resulting neurological syndrome. The Chisso Corporation chemical factory released methyl mercury into the Minamata Bay and this highly toxic compound was accumulated by fish and shellfish.
The Rotorua trout have also accumulated mercury, but Dr. Ngaire Phillips from the National Institute of Water and Atmospheric Research points out that the recommendation for consumption of no more than one trout per month is based on a lifetime consumption.
Friday, June 17, 2011
Colonel Mustard, in the Dining Room, with the Sprouts
The last couple of weeks have been like the old game of Cluedo, with everyone running round accusing various participant of foul play and trying to find the culprit. It would be amusing if it were not so deadly serious.
It now appears that the outbreak of Escherichia coli O104:H4 in Germany, which has now reached 16 countries, was probably caused by fresh vegetable sprouts grown in a farm in Uelzen, near Hamburg. Unfortunately, cucumbers from Spain, lettuces and tomatoes also had the finger pointed almost indiscriminately at them. That caused huge financial losses for the suppliers and had knock-on effects on vegetable sales throughout Europe. In some ways, I can sympathise with the authorities and the media. This is one of the largest and most serious outbreaks of food poisoning ever and finding the source as quickly as possibly was imperative.
At the time of writing, there have been 3517 cases of EHEC infection, resulting in an unprecedented 839 cases of Haemolytic Uraemic Syndrome and 39 deaths. The rate of new case reporting has slowed, but it is likely that more people will become ill before this is all over.
This shows just how difficult it is to pinpoint the source of an outbreak of food poisoning in our highly integrated and widespread food supply chain. The sprout farm purchased seeds for sprouting from both European and Asian countries. The seeds were sprouted, using what seems to be standard and well designed conditions, and the 18 different sprout mixtures were sent to many different points in Germany.
The German authorities have been accused of being in disarray and having no proper response prepared. There may be some truth in this - if the responsibility for food safety is spread across many local authorities and agencies, setting up a coordinated and timely response is fraught with difficulty. But it is generally recognised that epidemiological investigations may have a success rate as low as 33% in tracking down the source of infections and the chance of success falls as time goes on.
At times like this, we often hear calls for increased testing of products before they are released onto the market. Good try, but no cigar! For a number of reasons, microbiological testing to assure safety of food is just not possible. Testing is expensive and time consuming. In some cases, the testing period exceeds the shelf life of the product. A simple statistical calculation shows that when contamination levels are low, the number of samples that must be tested to get even a 95% chance of detection is prohibitively large and even then, 5% of contaminated samples will be accepted as safe. Testing for E. coli O157:H7 would not have picked up the German strain and even proposed widened testing for "The Big Six" Entero-Haemorrhagic E. coli strains would have missed this one.
Regulators must be strong in the coming months. Microbiological testing gives only a retrospective view and a poor one at that. Imposing increased mandatory testing will not assure the safety of foods.
The only way we can ensure the safety of our food supply is to introduce controlled lethal steps in processing, such as heating or irradiation, or to put in place rigorous control of every potentially hazardous ingredient, process step, processing facility and distribution chain. This is particularly important with high risk products such as sprouts. What every food producer and distributor needs is a Hazard Analysis based Food Safety Programme of Risk Management.
It now appears that the outbreak of Escherichia coli O104:H4 in Germany, which has now reached 16 countries, was probably caused by fresh vegetable sprouts grown in a farm in Uelzen, near Hamburg. Unfortunately, cucumbers from Spain, lettuces and tomatoes also had the finger pointed almost indiscriminately at them. That caused huge financial losses for the suppliers and had knock-on effects on vegetable sales throughout Europe. In some ways, I can sympathise with the authorities and the media. This is one of the largest and most serious outbreaks of food poisoning ever and finding the source as quickly as possibly was imperative.
At the time of writing, there have been 3517 cases of EHEC infection, resulting in an unprecedented 839 cases of Haemolytic Uraemic Syndrome and 39 deaths. The rate of new case reporting has slowed, but it is likely that more people will become ill before this is all over.
This shows just how difficult it is to pinpoint the source of an outbreak of food poisoning in our highly integrated and widespread food supply chain. The sprout farm purchased seeds for sprouting from both European and Asian countries. The seeds were sprouted, using what seems to be standard and well designed conditions, and the 18 different sprout mixtures were sent to many different points in Germany.
The German authorities have been accused of being in disarray and having no proper response prepared. There may be some truth in this - if the responsibility for food safety is spread across many local authorities and agencies, setting up a coordinated and timely response is fraught with difficulty. But it is generally recognised that epidemiological investigations may have a success rate as low as 33% in tracking down the source of infections and the chance of success falls as time goes on.
At times like this, we often hear calls for increased testing of products before they are released onto the market. Good try, but no cigar! For a number of reasons, microbiological testing to assure safety of food is just not possible. Testing is expensive and time consuming. In some cases, the testing period exceeds the shelf life of the product. A simple statistical calculation shows that when contamination levels are low, the number of samples that must be tested to get even a 95% chance of detection is prohibitively large and even then, 5% of contaminated samples will be accepted as safe. Testing for E. coli O157:H7 would not have picked up the German strain and even proposed widened testing for "The Big Six" Entero-Haemorrhagic E. coli strains would have missed this one.
Regulators must be strong in the coming months. Microbiological testing gives only a retrospective view and a poor one at that. Imposing increased mandatory testing will not assure the safety of foods.
The only way we can ensure the safety of our food supply is to introduce controlled lethal steps in processing, such as heating or irradiation, or to put in place rigorous control of every potentially hazardous ingredient, process step, processing facility and distribution chain. This is particularly important with high risk products such as sprouts. What every food producer and distributor needs is a Hazard Analysis based Food Safety Programme of Risk Management.
Friday, April 15, 2011
Tasty but occasionally dangerous
If I asked you to name a food group that might be implicated in food poisoning, you would probably respond with "meat". I did a survey (n=1) at home today and got that answer. My wife thought a bit longer and said "Custard, but that's only because you have influenced me over the years".
Baked goods probably don't spring to mind as potential carriers of food poisoning bacteria.
In the last week, there have been reports from Rhode Island of zeppole, or St. Joseph's Day cakes, causing food poisoning by Salmonella. I had never heard of zeppole before this report, but they are apparently popular in Italy, Sicily and Malta and in the Italian-American communities in the United States and date from the early 19th century. They are deep-fried dough balls, or sometimes choux pastry, topped with powdered sugar or filled with custard, pastry cream or a mixture of butter and honey. They sound delicious, though perhaps dangerous for the figure!
At the time of writing, there have been 76 cases and 29 hospitalisations. Two people have died from Salmonella-associated illness. It is too soon to say how this happened, but the possibilities include a carrier of Salmonella working as a food handler, or the use of ingredients contaminated with Salmonella. The deep-fried pastry would probably be sterile immediately after frying, but could be contaminated by the food handler during the filling process.
Breads, fruit cakes and biscuits are usually pretty safe by virtue of low water activity, but filled pastries receive quite a lot of handling, while real cream may be contaminated with bacteria that rapidly grow under abuse temperatures to the point where they can cause food poisoning, either by infection or intoxication.
Baked goods probably don't spring to mind as potential carriers of food poisoning bacteria.
In the last week, there have been reports from Rhode Island of zeppole, or St. Joseph's Day cakes, causing food poisoning by Salmonella. I had never heard of zeppole before this report, but they are apparently popular in Italy, Sicily and Malta and in the Italian-American communities in the United States and date from the early 19th century. They are deep-fried dough balls, or sometimes choux pastry, topped with powdered sugar or filled with custard, pastry cream or a mixture of butter and honey. They sound delicious, though perhaps dangerous for the figure!
At the time of writing, there have been 76 cases and 29 hospitalisations. Two people have died from Salmonella-associated illness. It is too soon to say how this happened, but the possibilities include a carrier of Salmonella working as a food handler, or the use of ingredients contaminated with Salmonella. The deep-fried pastry would probably be sterile immediately after frying, but could be contaminated by the food handler during the filling process.
Breads, fruit cakes and biscuits are usually pretty safe by virtue of low water activity, but filled pastries receive quite a lot of handling, while real cream may be contaminated with bacteria that rapidly grow under abuse temperatures to the point where they can cause food poisoning, either by infection or intoxication.
Monday, April 4, 2011
Will spoiled food make you sick?
I recently received a message from Jo, asking me to comment on this subject. Jo actually raised a lot of questions and, of course, the answers are not simple.
First question: If the food smells off, tastes bad, has a poor colour etc. is that a good indicator it will make you sick?
Humans have been on the Earth for a long time and one of the reasons they have survived for so long is that they have evolved self preservation mechanisms. If the food smells off or doesn't look right, there is a chance that it is poisonous in some way and we tend to avoid it. Sometimes I wonder what the first people to taste durian or blue cheese thought they were doing! So, clearly, the answer has to be a qualified "Yes, it might make you sick, but some sort of tribal wisdom suggests that a few foods can look and smell awful but still be OK to eat".
Jo then went on to say that she thought that the food was unlikely to make you sick, as the changes were caused by spoilage bacteria and enzymatic reactions, which are not the same as pathogenic bacteria, which she thought do not alter the food in the same way.
This is where it gets complicated. Spoilage bacteria do cause some changes, which, by definition, make the food unacceptable to most people. Other bacteria, such as Salmonella, may grow alongside the spoilage bacteria. When the food is eaten, the salmonellae set up an infection in the gut and produce the familiar food poisoning symptoms.
Second question: Is it true that pathogenic bacteria don't alter the food? Again, it depends on the bacteria. Generally, clostridia alter the food a lot, producing many smelly compounds and gas. This would put most people off eating the food, so they would be safe. But some Clostridium botulinum strains are non-proteolytic. That is, they don't break down proteins and they don't produce the foul smells that the proteolytic strains make. So you could find improperly processed canned foods that appear quite normal, but could kill you.
Jo's third question was perhaps the most fascinating: she was most interested in how the food could potentially have both types of bacteria on it near to the time it was made and correctly identified contamination of the food as the cause, possibly by cross-contamination from some source. A good example would be a careless food handler.
At this point, the food could cause food poisoning if consumed - Salmonella transferred from raw meat to a cream pastry would be a good example here.
Jo went on "However as time goes on and assuming the food gives them all the things they both need to grow, is it as simple as the pathogens might be around for a short time until the spoilage guys, who being better competitors for resources, take over; so by the time the food
is showing signs of being spoiled, the pathogens have been killed off?"
That's a really insightful comment. Many fermented foods are actually safe because of this pattern. Take raw cabbage and make sauerkraut: we shred the cabbage and add about 2.5% salt to it and then press it into a container and seal it. The salt draws out the tissue fluids from the shredded leaves and bacteria naturally on the leaves begin to produce lactic acid. If we sample on the first day, we can find all sorts of bacteria, including Escherichia coli and possibly Salmonella. However, as more acid is produced, the pH falls and the potential pathogens die off. Finished sauerkraut has a pH around 3.1 to 3.7 and is perfectly safe to eat, though there has been a lot of bacterial growth in it.
So, to return to Jo's original question, "Is spoiled food potentially safe to eat, even though it looks and tastes awful?" Sorry Jo, I can't answer that. But if it tastes awful, why would you want to eat it?
One last point: there is an anecdote that a lady opened a can of peas and thought that they looked a bit different. She tasted one and cooked the rest. She died of botulism. Ironically, if she had cooked them and then tasted one, she would have lived, as the botulin toxin is heat labile. I don't remember where I read this - it was somewhere around 1980, but it's a good example with which to finish this article.
First question: If the food smells off, tastes bad, has a poor colour etc. is that a good indicator it will make you sick?
Humans have been on the Earth for a long time and one of the reasons they have survived for so long is that they have evolved self preservation mechanisms. If the food smells off or doesn't look right, there is a chance that it is poisonous in some way and we tend to avoid it. Sometimes I wonder what the first people to taste durian or blue cheese thought they were doing! So, clearly, the answer has to be a qualified "Yes, it might make you sick, but some sort of tribal wisdom suggests that a few foods can look and smell awful but still be OK to eat".
Jo then went on to say that she thought that the food was unlikely to make you sick, as the changes were caused by spoilage bacteria and enzymatic reactions, which are not the same as pathogenic bacteria, which she thought do not alter the food in the same way.
This is where it gets complicated. Spoilage bacteria do cause some changes, which, by definition, make the food unacceptable to most people. Other bacteria, such as Salmonella, may grow alongside the spoilage bacteria. When the food is eaten, the salmonellae set up an infection in the gut and produce the familiar food poisoning symptoms.
Second question: Is it true that pathogenic bacteria don't alter the food? Again, it depends on the bacteria. Generally, clostridia alter the food a lot, producing many smelly compounds and gas. This would put most people off eating the food, so they would be safe. But some Clostridium botulinum strains are non-proteolytic. That is, they don't break down proteins and they don't produce the foul smells that the proteolytic strains make. So you could find improperly processed canned foods that appear quite normal, but could kill you.
Jo's third question was perhaps the most fascinating: she was most interested in how the food could potentially have both types of bacteria on it near to the time it was made and correctly identified contamination of the food as the cause, possibly by cross-contamination from some source. A good example would be a careless food handler.
At this point, the food could cause food poisoning if consumed - Salmonella transferred from raw meat to a cream pastry would be a good example here.
Jo went on "However as time goes on and assuming the food gives them all the things they both need to grow, is it as simple as the pathogens might be around for a short time until the spoilage guys, who being better competitors for resources, take over; so by the time the food
is showing signs of being spoiled, the pathogens have been killed off?"
That's a really insightful comment. Many fermented foods are actually safe because of this pattern. Take raw cabbage and make sauerkraut: we shred the cabbage and add about 2.5% salt to it and then press it into a container and seal it. The salt draws out the tissue fluids from the shredded leaves and bacteria naturally on the leaves begin to produce lactic acid. If we sample on the first day, we can find all sorts of bacteria, including Escherichia coli and possibly Salmonella. However, as more acid is produced, the pH falls and the potential pathogens die off. Finished sauerkraut has a pH around 3.1 to 3.7 and is perfectly safe to eat, though there has been a lot of bacterial growth in it.
So, to return to Jo's original question, "Is spoiled food potentially safe to eat, even though it looks and tastes awful?" Sorry Jo, I can't answer that. But if it tastes awful, why would you want to eat it?
One last point: there is an anecdote that a lady opened a can of peas and thought that they looked a bit different. She tasted one and cooked the rest. She died of botulism. Ironically, if she had cooked them and then tasted one, she would have lived, as the botulin toxin is heat labile. I don't remember where I read this - it was somewhere around 1980, but it's a good example with which to finish this article.
Thursday, March 3, 2011
More on Listeria contamination of vegetables
On 18th January 2011, I wrote about the withdrawal of salad vegetables from certain supermarkets in New Zealand because of possible contamination by Listeria (See Listeria Hysteria).
This week, I came across a paper published in Food Microbiology, describing the transfer of Listeria innocua from contaminated compost and irrigation water to lettuce leaves. (M. Oliveira et al. Food Microbiology 28 (2011) 590-596).
These authors noted in their introduction that "Fresh produce can become contaminated at any point during the primary production, processing, distribution and preparation. Primary sources of preharvest contamination include soil amended with untreated or improperly composted manure, contaminated irrigation water, the presence of wild and domestic animals, infected workers, and unclean containers and tools used in harvesting. Research has demonstrated that many human pathogens are able to survive for extended periods in soils, manure and water."
Listeria monocytogenes causes Listeriosis, a rare but serious disease in humans, with an incidence of 2-3 cases per million of the total population in England and Wales.
In their experiments, Oliveira et al used an avirulent strain - Listeria innocua. They transplanted lettuce seedlings into pots containing soil and contaminated compost; compost manually surface irrigated with contaminated water after the seedlings were transplanted; and treated a third set of seedlings by hand-spraying contaminated irrigation water onto the lettuce leaves after transplanting.
These workers reported that the lettuce leaves became contaminated with Listeria from the soil and, not surprisingly, sprinkling with contaminated water also resulted in contamination of the leaves with Listeria, which survived for some days. The bacteria survived in the compost for more than 9 weeks, giving ample opportunity for contamination of the leaves by transfer of soil.
Clearly, as these workers showed, irrigation water used for fresh salad vegetable growth must be pathogen free and manure used in compost must also be treated to remove pathogens.
This week, I came across a paper published in Food Microbiology, describing the transfer of Listeria innocua from contaminated compost and irrigation water to lettuce leaves. (M. Oliveira et al. Food Microbiology 28 (2011) 590-596).
These authors noted in their introduction that "Fresh produce can become contaminated at any point during the primary production, processing, distribution and preparation. Primary sources of preharvest contamination include soil amended with untreated or improperly composted manure, contaminated irrigation water, the presence of wild and domestic animals, infected workers, and unclean containers and tools used in harvesting. Research has demonstrated that many human pathogens are able to survive for extended periods in soils, manure and water."
Listeria monocytogenes causes Listeriosis, a rare but serious disease in humans, with an incidence of 2-3 cases per million of the total population in England and Wales.
In their experiments, Oliveira et al used an avirulent strain - Listeria innocua. They transplanted lettuce seedlings into pots containing soil and contaminated compost; compost manually surface irrigated with contaminated water after the seedlings were transplanted; and treated a third set of seedlings by hand-spraying contaminated irrigation water onto the lettuce leaves after transplanting.
These workers reported that the lettuce leaves became contaminated with Listeria from the soil and, not surprisingly, sprinkling with contaminated water also resulted in contamination of the leaves with Listeria, which survived for some days. The bacteria survived in the compost for more than 9 weeks, giving ample opportunity for contamination of the leaves by transfer of soil.
Clearly, as these workers showed, irrigation water used for fresh salad vegetable growth must be pathogen free and manure used in compost must also be treated to remove pathogens.
Monday, November 15, 2010
Do you really understand what's unsafe about your food?
There is a lot of concern about the safety of food. There is also a lot of misinformation and misunderstanding. Most of us have some concept of the dangers of the modern world, but our perception of risk, i.e. the probability that the hazard will become manifest, is often wide of the mark, perhaps influenced by publicity.
For example, most of us know that smoking is hazardous and that the risk of lung cancer and heart disease associated with smoking is high. Ask someone about the risk of flying in an airliner. If there has been a crash in the recent past, they may respond that flying is a high risk activity. The truth is that flying on a scheduled commercial flight is very safe. It's just that if an airliner crashes, it makes the news headlines all around the world, which influences our thinking.
Quite a long time ago, so long that I can't find the original reference, a few simple questions were put to food consumers. Food scientists assessed the actual risks. These people were asked "What is the food safety risk posed by the following?" What would your responses be?
Risk factor Perceived risk Actual risk
Microbial contamination Low High
Packaging failure Low High
Pesticide residues Medium Low
Irradiation High Very low
Recent events in the USA may have changed your perception, at least with respect to microbial contamination.
For example, most of us know that smoking is hazardous and that the risk of lung cancer and heart disease associated with smoking is high. Ask someone about the risk of flying in an airliner. If there has been a crash in the recent past, they may respond that flying is a high risk activity. The truth is that flying on a scheduled commercial flight is very safe. It's just that if an airliner crashes, it makes the news headlines all around the world, which influences our thinking.
Quite a long time ago, so long that I can't find the original reference, a few simple questions were put to food consumers. Food scientists assessed the actual risks. These people were asked "What is the food safety risk posed by the following?" What would your responses be?
Risk factor Perceived risk Actual risk
Microbial contamination Low High
Packaging failure Low High
Pesticide residues Medium Low
Irradiation High Very low
Recent events in the USA may have changed your perception, at least with respect to microbial contamination.
Wednesday, September 22, 2010
To test, or not to test – that is the question (with apologies to Shakespeare).
I had intended to write my next blog article on the latest information on Campylobacter in New Zealand. However, in view of the continuing Salmonella-in-eggs problem in the USA and yet another recall in New York State of ground beef owing to the detection of Salmonella, I decided to write about product testing and the alternatives.
It had been suggested that the feed was the source of Salmonella that infected the Wright County Egg Co. Reporting in the Wall Street Journal last week, Alicia Mundy and Bill Tomson wrote that the Food and Drug Administration had failed to detect Salmonella at the premises of the suppliers of the feed:
Officials warned that the investigation was continuing, but from my point of view, the fact that Salmonella was detected in the Wright County Egg Co. farm(s) on 426 occasions from 2008 to present is a pointer to the farms at least having some responsibility.
Testing of products, be they eggs, steaks or lettuces, can potentially detect Salmonella and other pathogenic bacteria, such as Escherichia coli O157:H7, allowing us to reject the lot. Unfortunately, testing doesn’t guarantee that we will detect Salmonella. In all sampling plans that I am aware of, detection of Salmonella in the sample is cause for rejection. Under the ICMSF 2-class attribute sampling plan nomenclature, ‘n’ is the number of samples to be taken from a lot, ‘c’ is the number of failures permitted and ‘m’ is the threshold above which the sample fails. Thus for Salmonella testing, c = 0 and m = 0. What number of samples should we take?
Statistics show us that when the frequency of contamination in the lot is 1 in 1000, setting c = 0 we would need to examine 2995 samples to achieve 95% confidence in detecting the defective sample; that is, we would still have a 5% chance of accepting a contaminated lot.
Put another way, extensive testing is prohibitively expensive, and many sampling plans call for only 5 samples to be taken from a lot. Even with 40% of the lot being defective, we would still accept the lot about 8% of the time.
So, testing seems a bit unreliable. Is there a better way? Well, yes there is. It’s called HACCP (Hazard Analysis Critical Control Points) and it came out of the space programme, developed initially as the Modes of Failure Programme by the Natick laboratory and then by The Pilsbury Corporation. Without going into detail on this occasion, it involves looking at the ingredients, the process and the processing facilities and looking for every way the food might become unsafe. These aspects are eliminated where possible and those hazards that cannot be eliminated are controlled by keeping tight control over Critical Control Points, such as cooking operations.
The hazard analysis can then be used to develop a Food Safety Programme for the factory. The factory runs the process according to this programme and monitors the CCPs and keeps accurate records of the entire process. There is then no need for end product testing – if the process is under control, safe food will be produced. Regulatory monitoring becomes a matter of checking the records and auditing the programme on a regular basis. This is a really good system and in a perfect world, it would work perfectly.
The problem with this approach is that the regulators need to have enough staff to do the inspections and the companies running the factory have to obey the rules, keep accurate records and come clean the minute something goes wrong. Companies must want to produce safe food, rather than just make money.
It is very sad that in many of the recent food poisoning outbreaks, it has eventually been shown that companies falsified records, while supposedly independent inspections were at best inadequate and at worst negligent and corrupt.
In this environment, the regulators need more staff, better legislation and more powers to shut down unsafe operations. I have watched in horror as one outbreak after another has resulted in severe injury to some consumers, massive food recalls and in some cases permanent shutdown of factories and wondered, “Where will it all end? Will there be any food manufacturers left in business? Will testing requirements become so onerous that food becomes ridiculously expensive?”
I don’t think there is an easy solution, but until the cowboys have all gone, I see no alternative to better legislation, more truly independent inspection, more frequent testing of product and full traceability of raw materials and finished products.
I don’t think there is an easy solution, but until the cowboys have all gone, I see no alternative to better legislation, more truly independent inspection, more frequent testing of product and full traceability of raw materials and finished products.
Sunday, June 27, 2010
Old lessons not learned - Re-post
I have just returned from a meeting of food experts in Wageningen, Holland. One evening, we were taken to the Zoo in Arnhem. This fantastic place has a number of indoor environments, such as a jungle, ocean, desert and a restaurant.
After the visit, we had a meal in the somewhat inappropriately named Burgers Zoo Restaurant. A feature of this is the do-it-yourself barbeque. This ingenious device is like the continuous toasters you see in some hotel dining rooms – the food is placed on a continuous belt grill and passes over heated briquettes. Diners select their meats and salads from the large range set out on side tables.
Not having completely switched out of professional mode, I watched my fellow foodies to see how they would cope. I guess I should not have been surprised to see several of them take their raw meats and salads onto a single plate. They cooked the meats and then put them back onto the same plate! Nobody took fresh tongs or heated the ones used to put the meat on the grill.
Clearly, not all the participants were experts in food safety, but I had hoped that they would know about basic food safety rules – cooked food should NEVER be put on a plate that has held uncooked meat and cross contamination of salads from raw meats must be avoided. When I pointed out their mistake to a couple of my colleagues, they understood, but still didn’t know what to do about it.
At the other end of the scale, one young lady expressed concern as to whether she had cooked her steak sufficiently and was she at risk of food poisoning? In my opinion, her meat was over-cooked, but it would certainly have been safe to eat. Raw steaks from a healthy animal are essentially sterile on the inside, so they can be made safe by cooking the outside properly. (Minced or ground meat has had the outside mixed into the inside, so cannot safely be eaten rare). She expressed the view that barbequing was a bloke’s job, but I wonder if it should be left to food microbiologists?
After the visit, we had a meal in the somewhat inappropriately named Burgers Zoo Restaurant. A feature of this is the do-it-yourself barbeque. This ingenious device is like the continuous toasters you see in some hotel dining rooms – the food is placed on a continuous belt grill and passes over heated briquettes. Diners select their meats and salads from the large range set out on side tables.
Not having completely switched out of professional mode, I watched my fellow foodies to see how they would cope. I guess I should not have been surprised to see several of them take their raw meats and salads onto a single plate. They cooked the meats and then put them back onto the same plate! Nobody took fresh tongs or heated the ones used to put the meat on the grill.
Clearly, not all the participants were experts in food safety, but I had hoped that they would know about basic food safety rules – cooked food should NEVER be put on a plate that has held uncooked meat and cross contamination of salads from raw meats must be avoided. When I pointed out their mistake to a couple of my colleagues, they understood, but still didn’t know what to do about it.
At the other end of the scale, one young lady expressed concern as to whether she had cooked her steak sufficiently and was she at risk of food poisoning? In my opinion, her meat was over-cooked, but it would certainly have been safe to eat. Raw steaks from a healthy animal are essentially sterile on the inside, so they can be made safe by cooking the outside properly. (Minced or ground meat has had the outside mixed into the inside, so cannot safely be eaten rare). She expressed the view that barbequing was a bloke’s job, but I wonder if it should be left to food microbiologists?
Wednesday, May 20, 2009
Can legislation control Salmonella?
Obviously, some very intelligent people think so. Unfortunately many of them misunderstand the control of food safety.
Food safety legislation is similar to the laws governing road traffic. There are lots of requirements for the design and maintenance of vehicles and prescribed behaviours for their operation. Maximum speeds for each piece of road are set by traffic authorities and advised by signs on the roads. If you exceed the speed limit, you might get away with it most of the time, but speed cameras may catch you. Then you get a ticket and a fine. That’s just money and perhaps demerit points on your licence. Do the speed signs and threat of punishment make us better or more responsible drivers?
Suppose we have an accident and injure or kill another motorist or pedestrian. If we are shown to be at fault, perhaps because of ignoring the speed limit, does the fact that we receive a stiff fine make it any better for the injured party or their family? No way.
The recent outbreak of salmonellosis in the US, carried in peanuts, was almost certainly the result of the flouting of many food safety regulations – the factory was dirty and infested and in-process peanuts were not protected from recontamination. Yet the factory had been inspected and the overall level of food safety was pronounced “superior”. It must be pointed out that the inspector was given only one day to inspect a factory processing several million pounds of peanuts each month and was not an expert in this type of operation. A federal investigation team later discovered that company testing records showed that Salmonella had been found in its products on at least 12 occasions since June 2007. Those products were apparently retested until negative results were obtained and then released to the market.
At least nine people have died from salmonellosis associated with the peanut products and 22,500 were sickened. The existing legislation clearly did not protect them. Some products containing the affected peanuts are apparently still on retail outlet shelves.
In a radio and television address to the American people on 14th March*, President Obama offered his “top ten” ideas for improving food safety. He noted that only about 5% of the 150,000 food production premises were inspected last year, so one billion dollars would be invested in the FDA to increase its ability to inspect premises. Penalties for selling unsafe food would be increased. Unfortunately, he then went on to state that only government can ensure that foods are safe to eat. Wrong, Mr. President!
Food safety is a partnership of trust between government, food producers and suppliers and the consumer. Sure, regulations are required and must be enforced, but no inspection force can guarantee the production and supply of safe food; the manufacturers must be committed to doing so on every day of the year, whether the inspector is due or not.
* http://www.youtube.com/watch?v=lkKp02lluq8
Food safety legislation is similar to the laws governing road traffic. There are lots of requirements for the design and maintenance of vehicles and prescribed behaviours for their operation. Maximum speeds for each piece of road are set by traffic authorities and advised by signs on the roads. If you exceed the speed limit, you might get away with it most of the time, but speed cameras may catch you. Then you get a ticket and a fine. That’s just money and perhaps demerit points on your licence. Do the speed signs and threat of punishment make us better or more responsible drivers?
Suppose we have an accident and injure or kill another motorist or pedestrian. If we are shown to be at fault, perhaps because of ignoring the speed limit, does the fact that we receive a stiff fine make it any better for the injured party or their family? No way.
The recent outbreak of salmonellosis in the US, carried in peanuts, was almost certainly the result of the flouting of many food safety regulations – the factory was dirty and infested and in-process peanuts were not protected from recontamination. Yet the factory had been inspected and the overall level of food safety was pronounced “superior”. It must be pointed out that the inspector was given only one day to inspect a factory processing several million pounds of peanuts each month and was not an expert in this type of operation. A federal investigation team later discovered that company testing records showed that Salmonella had been found in its products on at least 12 occasions since June 2007. Those products were apparently retested until negative results were obtained and then released to the market.
At least nine people have died from salmonellosis associated with the peanut products and 22,500 were sickened. The existing legislation clearly did not protect them. Some products containing the affected peanuts are apparently still on retail outlet shelves.
In a radio and television address to the American people on 14th March*, President Obama offered his “top ten” ideas for improving food safety. He noted that only about 5% of the 150,000 food production premises were inspected last year, so one billion dollars would be invested in the FDA to increase its ability to inspect premises. Penalties for selling unsafe food would be increased. Unfortunately, he then went on to state that only government can ensure that foods are safe to eat. Wrong, Mr. President!
Food safety is a partnership of trust between government, food producers and suppliers and the consumer. Sure, regulations are required and must be enforced, but no inspection force can guarantee the production and supply of safe food; the manufacturers must be committed to doing so on every day of the year, whether the inspector is due or not.
* http://www.youtube.com/watch?v=lkKp02lluq8
Tuesday, April 14, 2009
Black-balled peas
If Talleys of New Zealand have been correctly reported, it seems to me that they have placed the wrong priority on their response to the complaint by Humphrey Elton about his finding Black Nightshade berries in a pack of frozen peas last August. A number of other contaminated packs of peas and beans have turned up since then, the latest being frozen peas and corn last week. One complainant has claimed that almost half of the peas were actually Black Nightshade. If that really is the case, then there is a serious problem in the factory or on the farms.
According to Mr. Elton, Talleys informed him that this is a common agricultural weed and nothing to worry about. He received a cheque for five dollars as compensation.
The New Zealand Food Safety Authority has noted that the berries are “mildly toxic and should be avoided; the contamination is a food quality issue”. It seems that it has been an issue for at least 8 months, but for some reason has only recently hit the headlines.
The fact is, Mr Elton and other consumers bought frozen vegetables. They did not expect to receive anything else in the pack. Being told that the berries are nothing to worry about is akin to complaining to the waiter about a fly in the soup and then being told not to let other diners hear - it’s extra protein and a bonus.
In a world where consumers are highly aware of food safety and quality, I would have expected a more pro-active response from the company. They could have told the complainants that they were very sorry about the contamination and that they were investigating the occurrence and should not have offered such a miserly compensation. If the problem has been known since last year, they should have been doing something about it long ago. What a difference this would have made to the public perception of the company. The downside is that Paul Henry (TVone Breakfast host) would have been robbed of an opportunity to clown around, testing frozen peas by hitting them with a mallet on the Breakfast table.
How could the contamination have occurred? The most likely causes are excessive growth of Black Nightshade in the fields as a result of favourable weather conditions and failure to control this growth by suitable spraying. When the peas are harvested, a harvesting machine cuts the whole pea vine and separates the peas from the other parts of the plant. The harvester cannot differentiate peas from nightshade berries. Sorting and separation in the processing plant was obviously ineffective.
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