I hope that caught your attention. I suppose you could argue that it was clickbait. The animals didn't literally walk to the landfill, but 6.9 million pounds of ground beef were recalled last week by a company called JBS because of fears that the meat was contaminated by Salmonella enterica serotype Newport (otherwise known as S. Newport).
There is a really good article on this recall by Joe Fassler in The New Food Economy.
FSIS was notified of a salmonellosis outbreak on 5th September 2018 and subsequent traceback indicated that JBS was the common source. By 6th September, 57 patients in 16 states were identified as having Salmonellosis. The strain of S. Newport in this outbreak is being reported as being multiple antibiotic resistant, though, as far as I am aware, this reporting is based on previous outbreaks. Antibiotics are not normally used in treatment of human salmonellosis. Experts have also pointed out that cattle are the most common source of S. Newport.
As with many large outbreaks, the situtation is at best muddy. In general, Salmonella is found much less frequently in cattle herds than in chicken flocks. It is not considered an adulterant by the regulators. In some herds, the incidence of Salmonella is zero; in others it has been found at up to 53%. Salmonella enters the meat as a result of faecal contamination, from the animals or from the processing equipment. Processors are not required to test for Salmonella, so JBS would not have been aware of its presence in its products. Dairy cattle are not bred for meat production, but sick, low yielding cows are often culled and sent to meat works, where the meat, not being primal cuts, is ground and used with other meat in burger patties. Thus, the potentially contaminated meat is spread extensively throughout the production. You might argue that the company should test its products for Salmonella even though this is not a requirement. However, microbiological testing is actually unreliable as a food safety control, mainly because of the problem of getting a meaningful sample from the food, particularly if the contamination is at a low level.
Since the processors are not required to test for Salmonella, they cannot be compelled to recall the potentially contaminated product, but JBS has done this voluntarily. Well done!
However, several questions remain: why was this meat implicated in causing salmonellosis? There are probably many answers to this. Americans like their hamburgers rare or medium rare. USDA raised the minimum temperature for cooked hamburgers to 160 degrees Farenheit (71.1 degrees Celsius). Provided that this internal temperature is reached, Salmonella will be killed. But kitchen hygiene is also critical. If raw hamburger patties or mince are handled, cross contamination to other equipment, surfaces and foods can occur. (Think next time you barbeque meat patties: did your utensils contact the raw meat and then the cooked meat? I once attended a Korean BBQ where raw meat was put on a plate and then cooked before being put back onto the same plate!) Was the processing equipment thoroughly washed down and sanitised after each shift, or is there a possibiliy that the bacteria had colonised the plant, allowing continuous inoculation of the product? Certain designs of equipment are notorious for being very difficult to clean and providing niches for colonisation.
A more general and worrying question: S. Newport is most commonly found in cattle and antibiotics are not normally used in treatment of human salmonellosis. Why are we finding multiple antibiotic resistant S. Newport strains?
Take-home message: treat all meat as potentially contaminated with pathogens like Salmonella. Handle it carefully and cook it properly.
Showing posts with label Food recall. Show all posts
Showing posts with label Food recall. Show all posts
Tuesday, October 9, 2018
Wednesday, August 28, 2013
Clostridium in whey protein turns out not to be C. botulinum
The Ministry of Primary Industry today made a statement that tests on the Clostridium species isolated from Fonterra whey protein concentrate show that it is not C. botulinum. The organism is C. sporogenes and poses no food poisoning threat.
This will be a huge relief to Fonterra, the New Zealand government and MPI, not to mention hundreds of parents of babies being fed on infant formula. However, the damage to the company's reputation and the Pure New Zealand brand has been massive. Even countries that did not receive any of the affected powder and formulae have banned the import of New Zealand dairy products.
Why has it taken so long to get a definitive answer and why did the company recall the product?
Tests of products that incorporated certain batches of whey protein concentrate showed growth of sulphite reducing clostridia, though the protein concentrate itself was within specification. Further testing of the bacterial isolates suggested that they might be C. botulinum. Because of the severity of the illness that this microorganism can cause, the company withdrew certain batches of whey protein concentrate from the market and advised its customers accordingly.
It is quite difficult to distinguish certain closely related types of bacteria, and this is the case with C. botulinum and C. sporogenes. The bacteria have to be isolated in pure culture, various biochemical tests must be performed, DNA must be extracted and PCR reactions carried out with specific primers. While this sounds easy, and appears to be very rapid if the CSI-type of TV programmes are to be believed, in practice it is very tricky and time consuming. Extracting the DNA from the bacteria without its being degraded by DNAse enzymes is apparently difficult. There are few laboratories in the world capable of carrying out the testing reliably. (This is not a bacterium to be trifled with. When I worked in England for a year at the Food Research Institute in Norwich, only vaccinated people were permitted to go into the botulinum laboratory because of the risk to workers of lethal intoxication). The 'gold standard' test for toxigenic C. botulinum capable of causing the neuroparalysis is the mouse lethality test. This must be performed very precisely, according to an internationally recognised approved procedure and involves specially bred mice of a particular age. The various tests have now been completed, allowing the announcement from MPI today.
Did Fonterra do the right thing in notifying its customers of the potentially hazardous product and recalling the protein concentrate? In my opinion, they did. Certainly, it has caused the company embarrassment and financial loss, but what of the other option - keeping quiet and hoping the problem would go away? The death of even a single baby from botulism would have been far more damaging, and devastating for the parents.
Will things change in the future? Only time will tell what regulatory changes may follow, and new testing requirements are imposed. One thing is sure: occasionally, food manufacturers will make a mistake; equipment will malfunction, or a set of circumstances will come together that result in potentially unsafe food. The entire food industry must strive to reduce the frequency of these incidents to an absolute minimum by close process control, based on appropriate and robust risk assessment and hazard control measures.
This will be a huge relief to Fonterra, the New Zealand government and MPI, not to mention hundreds of parents of babies being fed on infant formula. However, the damage to the company's reputation and the Pure New Zealand brand has been massive. Even countries that did not receive any of the affected powder and formulae have banned the import of New Zealand dairy products.
Why has it taken so long to get a definitive answer and why did the company recall the product?
Tests of products that incorporated certain batches of whey protein concentrate showed growth of sulphite reducing clostridia, though the protein concentrate itself was within specification. Further testing of the bacterial isolates suggested that they might be C. botulinum. Because of the severity of the illness that this microorganism can cause, the company withdrew certain batches of whey protein concentrate from the market and advised its customers accordingly.
It is quite difficult to distinguish certain closely related types of bacteria, and this is the case with C. botulinum and C. sporogenes. The bacteria have to be isolated in pure culture, various biochemical tests must be performed, DNA must be extracted and PCR reactions carried out with specific primers. While this sounds easy, and appears to be very rapid if the CSI-type of TV programmes are to be believed, in practice it is very tricky and time consuming. Extracting the DNA from the bacteria without its being degraded by DNAse enzymes is apparently difficult. There are few laboratories in the world capable of carrying out the testing reliably. (This is not a bacterium to be trifled with. When I worked in England for a year at the Food Research Institute in Norwich, only vaccinated people were permitted to go into the botulinum laboratory because of the risk to workers of lethal intoxication). The 'gold standard' test for toxigenic C. botulinum capable of causing the neuroparalysis is the mouse lethality test. This must be performed very precisely, according to an internationally recognised approved procedure and involves specially bred mice of a particular age. The various tests have now been completed, allowing the announcement from MPI today.
Did Fonterra do the right thing in notifying its customers of the potentially hazardous product and recalling the protein concentrate? In my opinion, they did. Certainly, it has caused the company embarrassment and financial loss, but what of the other option - keeping quiet and hoping the problem would go away? The death of even a single baby from botulism would have been far more damaging, and devastating for the parents.
Will things change in the future? Only time will tell what regulatory changes may follow, and new testing requirements are imposed. One thing is sure: occasionally, food manufacturers will make a mistake; equipment will malfunction, or a set of circumstances will come together that result in potentially unsafe food. The entire food industry must strive to reduce the frequency of these incidents to an absolute minimum by close process control, based on appropriate and robust risk assessment and hazard control measures.
Saturday, March 31, 2012
Bacteria in canned food
Looking through the search terms that produced hits on Safe Food this month, I came across "Listeria in canned food".
Is canned food hazardous from the point of view of Listeria? In my opinion, the answer is "No" with just one small caveat: "unless the food has been grossly underprocessed, or post- processing contamination has occurred".
Canned foods are divided into two main categories: Low Acid (LACF) and Acid Canned foods (ACF). The dividing line is pH 4.6, low acid foods having a pH greater than this, and acid food having a pH lower than 4.6.
The significance of this pH value is that Clostridium botulinum can grow at pH above 4.6.
C. botulinum is able to form very heat resistant spores and can grow in the anaerobic conditions in canned food. Since C. botulinum also produces a lethal toxin, it is essential to destroy the spores. So we heat the food in the cans to temperatures above boiling point (in fact we heat to the equivalent of 121.1C for 2.52 minutes and this is called a 12D process). Properly processed LACF is safe.
When we look at acid foods, we find that C. botulinum is incapable of growth under these acid conditions and so no toxin can be produced. Since we don't need to deliver a 12D process, we can heat for a shorter time or at lower temperature. This has the advantage that the food is changed less and it costs less to deliver the process. Depending on the food and the degree of acidity, we really need only destroy vegetative (i.e. non-sporulating) pathogens and spoilage microorganisms. This will then destroy Listeria.
What about my conditional clause above? If the food canner doesn't properly control the process, it might be possible for cans to be underprocessed. This might occur if the steam supply to the retort (pressure cooker) is lacking or turned off too soon. Another possibility is that cans might by-pass the retort altogether.
Post-processing contamination could occur if the cooling water is contaminated. The can seals are not 100% watertight while they are still hot, so using contaminated water may allow a few bacteria to enter the can during cooling. This resulted in a typhoid outbreak in Aberdeen in 1964, when people consumed imported Argentinian canned corned beef that was cooled in untreated, sewage-contaminated river water.
Damage to the can seams caused by rough handling can also allow contamination, as there is a partial vacuum in the can. Momentary opening of the seam caused by a blow can permit bacteria to be drawn into the can.
In summary, providing cans are properly processed and handled with reasonable care, LACF are essentially sterile, so all bacteria, including Listeria will have been killed; ACF are pasteurised and this process will also kill Listeria.
Is canned food hazardous from the point of view of Listeria? In my opinion, the answer is "No" with just one small caveat: "unless the food has been grossly underprocessed, or post- processing contamination has occurred".
Canned foods are divided into two main categories: Low Acid (LACF) and Acid Canned foods (ACF). The dividing line is pH 4.6, low acid foods having a pH greater than this, and acid food having a pH lower than 4.6.
The significance of this pH value is that Clostridium botulinum can grow at pH above 4.6.
C. botulinum is able to form very heat resistant spores and can grow in the anaerobic conditions in canned food. Since C. botulinum also produces a lethal toxin, it is essential to destroy the spores. So we heat the food in the cans to temperatures above boiling point (in fact we heat to the equivalent of 121.1C for 2.52 minutes and this is called a 12D process). Properly processed LACF is safe.
When we look at acid foods, we find that C. botulinum is incapable of growth under these acid conditions and so no toxin can be produced. Since we don't need to deliver a 12D process, we can heat for a shorter time or at lower temperature. This has the advantage that the food is changed less and it costs less to deliver the process. Depending on the food and the degree of acidity, we really need only destroy vegetative (i.e. non-sporulating) pathogens and spoilage microorganisms. This will then destroy Listeria.
What about my conditional clause above? If the food canner doesn't properly control the process, it might be possible for cans to be underprocessed. This might occur if the steam supply to the retort (pressure cooker) is lacking or turned off too soon. Another possibility is that cans might by-pass the retort altogether.
Post-processing contamination could occur if the cooling water is contaminated. The can seals are not 100% watertight while they are still hot, so using contaminated water may allow a few bacteria to enter the can during cooling. This resulted in a typhoid outbreak in Aberdeen in 1964, when people consumed imported Argentinian canned corned beef that was cooled in untreated, sewage-contaminated river water.
Damage to the can seams caused by rough handling can also allow contamination, as there is a partial vacuum in the can. Momentary opening of the seam caused by a blow can permit bacteria to be drawn into the can.
In summary, providing cans are properly processed and handled with reasonable care, LACF are essentially sterile, so all bacteria, including Listeria will have been killed; ACF are pasteurised and this process will also kill Listeria.
Monday, January 9, 2012
Moulds and mycotoxins
Pepin Heights Orchards and Minnesota Department of Agriculture have issued advice to consumers not to drink certain batches of Honeycrisp Apple Cider because of the presence of patulin at levels slightly above the 50 microgram per litre maximum level recommended by the World health Organisation. See: http://www.prweb.com/releases/2012/1/prweb9085429.htm
Patulin is one of a host of compounds produced by moulds. These compounds are collectively referred to as "Mycotoxins".
We don't hear a lot about mycotoxins in the popular press - outbreaks of food borne illness are usually caused by Salmonella, Listeria, Campylobacter, or Escherichia coli, with several other bit players.
In fact, many fungi produce mycotoxins. One of my older textbooks devotes 66 pages of its 750 to these chemicals, some of which are very complex molecules. There is considerable discussion as to why moulds produce them, but they are probably just by-products of metabolism, though it has been suggested that in some cases, excretion of these "secondary metabolites" may confer some selective advantage, perhaps by inhibiting competitors in the soil.
Some of these chemicals can be very toxic - I well remember 1960 as the year when it was not possible to buy a turkey for Christmas in the UK, because thousands of young turkeys on poulry farms had died of the mysterious "Turkey X Disease". This was later shown to be caused by Aflatoxin present in peanut meal from Brazil as a result of growth of Aspergillus flavus mould. Intoxication of both humans and animals may be acute, but long term exposure may lead to cancer development.
Patulin in not regarded as particularly toxic to humans, but its presence in apple products is an indication of the quality of the apples used to make the products. There is some inconclusive evidence that patulin is genotoxic, i.e. it can damage the cell's genetic material. Pepin Heights has therefore been very responsible in their actions.
In America, fresh pressed apple juice is called Cider. In Europe, Cider, or Cidre is fermented apple juice. Patulin does not survive the fermentation process, so fermented cider is not likely to be contaminated with patulin.
Odd spot: a numbeer of mycotoxins are beneficial to humans, as they are in fact antibiotics - penicillin is just one example. Many drugs have also been made from mycotoxins.
St Anthony's Fire - ergot poisoning, has been known since about 600 BCE, but the pure ergotamine can be used to treat migraine.
For a much more complete, but readable, description of mycotoxins, go to: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC164220/
Patulin is one of a host of compounds produced by moulds. These compounds are collectively referred to as "Mycotoxins".
We don't hear a lot about mycotoxins in the popular press - outbreaks of food borne illness are usually caused by Salmonella, Listeria, Campylobacter, or Escherichia coli, with several other bit players.
In fact, many fungi produce mycotoxins. One of my older textbooks devotes 66 pages of its 750 to these chemicals, some of which are very complex molecules. There is considerable discussion as to why moulds produce them, but they are probably just by-products of metabolism, though it has been suggested that in some cases, excretion of these "secondary metabolites" may confer some selective advantage, perhaps by inhibiting competitors in the soil.
Some of these chemicals can be very toxic - I well remember 1960 as the year when it was not possible to buy a turkey for Christmas in the UK, because thousands of young turkeys on poulry farms had died of the mysterious "Turkey X Disease". This was later shown to be caused by Aflatoxin present in peanut meal from Brazil as a result of growth of Aspergillus flavus mould. Intoxication of both humans and animals may be acute, but long term exposure may lead to cancer development.
Patulin in not regarded as particularly toxic to humans, but its presence in apple products is an indication of the quality of the apples used to make the products. There is some inconclusive evidence that patulin is genotoxic, i.e. it can damage the cell's genetic material. Pepin Heights has therefore been very responsible in their actions.
In America, fresh pressed apple juice is called Cider. In Europe, Cider, or Cidre is fermented apple juice. Patulin does not survive the fermentation process, so fermented cider is not likely to be contaminated with patulin.
Odd spot: a numbeer of mycotoxins are beneficial to humans, as they are in fact antibiotics - penicillin is just one example. Many drugs have also been made from mycotoxins.
St Anthony's Fire - ergot poisoning, has been known since about 600 BCE, but the pure ergotamine can be used to treat migraine.
For a much more complete, but readable, description of mycotoxins, go to: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC164220/
Wednesday, October 5, 2011
Ten Biggest Food Recalls in US History - link
I was recently contacted by a reader who included a link to a commercial website. I would not normally publish such a comment, but this site does contain useful information, primarily for American businesses.
The page she specifically included lists ten very large food recalls in the US. I'm not sure if they are listed in order of cost, volume of product or effect on consumers, and there is only minimal detail. However, I have included the link here so that interested readers may search further to obtain more detail on these recalls.
http://www.businessinsurance.org/10-biggest-food-recalls-in-u-s-history/
The page she specifically included lists ten very large food recalls in the US. I'm not sure if they are listed in order of cost, volume of product or effect on consumers, and there is only minimal detail. However, I have included the link here so that interested readers may search further to obtain more detail on these recalls.
http://www.businessinsurance.org/10-biggest-food-recalls-in-u-s-history/
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