Readers may have been concerned to hear last week of 24 unexplained deaths among patients with acute pancreatitis, who were being administered probiotics in a study conducted at the University Medical Centre in Utrecht. The deaths occurred between 2004 and 2007 and represented 16% of the 296 patients in the trial. Unfortunately, the original reports are in Dutch and it is difficult to glean the full facts, including the percentage of patients in the control group who died.
It appears that the patients all had serious acute pancreatitis – inflammation of the pancreas. This disease may have a number of causes, but alcohol abuse and gallstones account for 80-90% of cases. Scarring of the pancreas during an attack may lead to chronic disease that can become life threatening.
The research concerned the functioning of probiotic bacteria administered to reduce the effects of the pancreatitis. The investigation was conducted in fifteen hospitals under the guidance of UMC Utrecht. If I have interpreted the press reports correctly, an investigation of the deceased showed that no infection resulted from the administration of the probiotics. However, three factors appear to be involved: treatment with probiotics of patients having organ failure; treatment of patients in intensive care; treatment of patients being fed by probe directly into the digestive tract. The researchers have recommended that if a patient satisfies one or more of these criteria, they should not be administered probiotics. A similar trial in Czechia has been stopped.
It had been thought that the administration of probiotic bacteria would raise the patients’ resistance to detrimental bacteria colonizing the gut.
Not surprisingly, the main manufacturers of probiotic cultures have reacted strongly, stating that there is no evidence that feeding of probiotics has a deleterious effect on healthy individuals. They have also claimed that the bacteria in the study are different from those in their own products.
I’m sure we haven’t heard the last of this, but in the meantime I suggest that normal, healthy adults should continue eating their probiotic-containing yoghurt or drinking their daily dose of probiotic cultures. The benefits of probiotic bacteria have been known for many years and countless people have consumed them without apparent ill effects. Extrapolating from patients who were already seriously unwell to normal healthy individuals is ill advised.
This morning my muesli and strawberries tasted just great with the addition of probiotic yoghurt!
Sunday, February 3, 2008
Tuesday, January 22, 2008
Hazardous Home-made Ice Cream
We’ve probably all eaten and enjoyed home-made ice cream at some time in our lives. It can be great fun for kids to help Mum make it during the summer holidays.
During the recent summer holiday (Southern Hemisphere), my neighbour gave me a recipe for making ice cream. It seemed simple enough – just combining eggs and cream, vanilla and sugar and then freezing it, stirring at intervals. “The children just love it”. There was no mention of pasteurization, which made me uncomfortable.
I looked for “Ice cream home made” on Google and found many recipes, some of which used eggs. Some included heating steps, some didn’t. This is worrying.
Eggs can potentially be infected with Salmonella during formation in the hen. External contamination can also occur, which may be transferred to the egg contents when the shell is cracked. The egg industry has procedures in place to minimize these risks and commercial egg pulp is pasteurized. This is a fairly delicate balance between providing sufficient heat to kill pathogenic bacteria and not causing the egg proteins to denature.
If you are going to make ice cream at home this summer, I recommend that you either use a recipe that does not call for eggs, or that you use a process that heats the eggs. A typical recipe can be found at:
http://www.cooks.com/rec/doc/0,1613,150189-248198,00.html
where the following instruction is given: “In heavy 3 quart saucepan with wire whisk, combine sugar, flour and salt. Beat in milk and eggs until well blended. Cook over medium low heat, stirring frequently, until mixture thickens and coats spoon, about 30 to 45 minutes. (Do not boil or mixture will curdle.) Cover surface with plastic wrap; cool completely, about 3 hours”.
The temperature of the egg mix needs to get high enough to kill Salmonella bacteria if they are present. This can be achieved by heating the mix to 80C and holding it for 15 seconds.
During the recent summer holiday (Southern Hemisphere), my neighbour gave me a recipe for making ice cream. It seemed simple enough – just combining eggs and cream, vanilla and sugar and then freezing it, stirring at intervals. “The children just love it”. There was no mention of pasteurization, which made me uncomfortable.
I looked for “Ice cream home made” on Google and found many recipes, some of which used eggs. Some included heating steps, some didn’t. This is worrying.
Eggs can potentially be infected with Salmonella during formation in the hen. External contamination can also occur, which may be transferred to the egg contents when the shell is cracked. The egg industry has procedures in place to minimize these risks and commercial egg pulp is pasteurized. This is a fairly delicate balance between providing sufficient heat to kill pathogenic bacteria and not causing the egg proteins to denature.
If you are going to make ice cream at home this summer, I recommend that you either use a recipe that does not call for eggs, or that you use a process that heats the eggs. A typical recipe can be found at:
http://www.cooks.com/rec/doc/0,1613,150189-248198,00.html
where the following instruction is given: “In heavy 3 quart saucepan with wire whisk, combine sugar, flour and salt. Beat in milk and eggs until well blended. Cook over medium low heat, stirring frequently, until mixture thickens and coats spoon, about 30 to 45 minutes. (Do not boil or mixture will curdle.) Cover surface with plastic wrap; cool completely, about 3 hours”.
The temperature of the egg mix needs to get high enough to kill Salmonella bacteria if they are present. This can be achieved by heating the mix to 80C and holding it for 15 seconds.
Monday, January 14, 2008
Botulism is back
Botulism is back in the news. The US Food and Drug Administration has announced that a canning company in Michigan is recalling certain lots of canned beans. The reason given was that these particular batches of product were not adequately heated during the processing.
As I wrote in “Deadly Poison in the Kitchen” on 5th September last year, the testing of canned foods for Clostridium botulinum is impractical. No sampling plan could detect the very low level of faulty cans that we accept. We are therefore totally reliant on the correct delivery of the thermal process by the manufacturer. Not surprisingly, the regulations covering the processing of Low Acid Canned Foods* are tight and specific.
The cans must be heated in a pressurized vessel called a retort at temperatures greater than 100C (the temperature of boiling water) because the C. botulinum spores are very heat resistant. They can survive for longer than 4 hours in boiling water. Full records must be made of the process, using special controllers and monitoring instruments. The retort operator must sign these records as soon as the cooking process is completed and they must be inspected and signed off by a responsible member of Management within 24 hours.
I don’t know the details of the investigation, other than the information provided in the FDA announcement (http://www.fda.gov/oc/po/firmrecalls/newera01_08.html). However, it does appear that the procedures mentioned above were not followed. The FDA announcement, quoting the company, stated that the recall was made “because a records review identified the possibility that a small number of cans from each lot may not have been adequately cooked”. These cans should not have entered the distribution network until after the processing records had been inspected.
For the benefit of anyone who has concerns about the hazards of handling foods thought to be contaminated with the toxin (botulin) I have quoted the FDA release verbatim below:
“Any food that may be contaminated should be disposed of carefully. Even tiny amounts of toxins ingested, inhaled, or absorbed through the eye or a break in the skin can cause serious illness. Skin contact should be avoided as much as possible, and the hands should be washed immediately after handling the food. Customers who have the product or any foods made with these products should throw them away immediately. Double bag the cans in plastic bags that are tightly closed, then place in a trash receptacle for non-recyclable trash outside of the home. Restaurants and institutions are encouraged to assure that such products are only placed in locked receptacles which are not accessible to the public. Additional instructions for safe disposal can be found at www.cdc.gov/botulism/botulism_faq.htm. Anyone with questions can call FDA at 1-888-SAFEFOOD”.
* A Low Acid Canned Food (LACF) is defined as a food packed in an hermetically sealed container, whose finished equilibrium pH is greater than 4.6 This includes, but is not limited to foods like canned beans, peas, carrots, corn etc. It is not safe to try to make these products at home and industrial production must be conducted in approved premises, using processes approved by thermal processing experts and filed with the authority (in the US this will be either FDA or USDA; in New Zealand it is NZFSA).
As I wrote in “Deadly Poison in the Kitchen” on 5th September last year, the testing of canned foods for Clostridium botulinum is impractical. No sampling plan could detect the very low level of faulty cans that we accept. We are therefore totally reliant on the correct delivery of the thermal process by the manufacturer. Not surprisingly, the regulations covering the processing of Low Acid Canned Foods* are tight and specific.
The cans must be heated in a pressurized vessel called a retort at temperatures greater than 100C (the temperature of boiling water) because the C. botulinum spores are very heat resistant. They can survive for longer than 4 hours in boiling water. Full records must be made of the process, using special controllers and monitoring instruments. The retort operator must sign these records as soon as the cooking process is completed and they must be inspected and signed off by a responsible member of Management within 24 hours.
I don’t know the details of the investigation, other than the information provided in the FDA announcement (http://www.fda.gov/oc/po/firmrecalls/newera01_08.html). However, it does appear that the procedures mentioned above were not followed. The FDA announcement, quoting the company, stated that the recall was made “because a records review identified the possibility that a small number of cans from each lot may not have been adequately cooked”. These cans should not have entered the distribution network until after the processing records had been inspected.
For the benefit of anyone who has concerns about the hazards of handling foods thought to be contaminated with the toxin (botulin) I have quoted the FDA release verbatim below:
“Any food that may be contaminated should be disposed of carefully. Even tiny amounts of toxins ingested, inhaled, or absorbed through the eye or a break in the skin can cause serious illness. Skin contact should be avoided as much as possible, and the hands should be washed immediately after handling the food. Customers who have the product or any foods made with these products should throw them away immediately. Double bag the cans in plastic bags that are tightly closed, then place in a trash receptacle for non-recyclable trash outside of the home. Restaurants and institutions are encouraged to assure that such products are only placed in locked receptacles which are not accessible to the public. Additional instructions for safe disposal can be found at www.cdc.gov/botulism/botulism_faq.htm. Anyone with questions can call FDA at 1-888-SAFEFOOD”.
* A Low Acid Canned Food (LACF) is defined as a food packed in an hermetically sealed container, whose finished equilibrium pH is greater than 4.6 This includes, but is not limited to foods like canned beans, peas, carrots, corn etc. It is not safe to try to make these products at home and industrial production must be conducted in approved premises, using processes approved by thermal processing experts and filed with the authority (in the US this will be either FDA or USDA; in New Zealand it is NZFSA).
Tuesday, December 18, 2007
Vegetables and all that jazz
This item properly belongs somewhere other than in a food safety blog. However, in the spirit of the festive season, I couldn’t resist submitting it.
I saw a concert advertised while I was in Hong Kong. There are lots of concerts there, but this one particularly caught my fancy. An Austrian orchestra was to perform a fusion of the most diverse music styles: contemporary music, beat-oriented House tracks, experimental electronic, free jazz, Noise, Dub and Clicks'n'Cuts, etc. on instruments made of fresh vegetables.
“The ensemble overcomes preserved and marinated sound conceptions or tirelessly re-stewed listening habits, putting its focus on expanding the variety of vegetable instruments, developing novel musical ideas and exploring fresh vegetable sound gardens”.
Apparently, the group would play carrot flutes, pumpkin basses, leek violins, eggplant clappers, cucumberophones, celery bongos and numerous other vegetables. The instruments were made by the Vienna Vegetable Orchestra before each performance and were to be cooked in a soup afterwards and served to some members of the audience. (I know that being a musician is a poorly paid profession, but surviving on Rhythm and Gruel is a tough life).
If you think that this article might be a Christmas Con(cert), go to the orchestra’s website and watch their U-Tube video: http://www.gemueseorchester.org/
Happy Christmas, everyone,
John Brooks.
I saw a concert advertised while I was in Hong Kong. There are lots of concerts there, but this one particularly caught my fancy. An Austrian orchestra was to perform a fusion of the most diverse music styles: contemporary music, beat-oriented House tracks, experimental electronic, free jazz, Noise, Dub and Clicks'n'Cuts, etc. on instruments made of fresh vegetables.
“The ensemble overcomes preserved and marinated sound conceptions or tirelessly re-stewed listening habits, putting its focus on expanding the variety of vegetable instruments, developing novel musical ideas and exploring fresh vegetable sound gardens”.
Apparently, the group would play carrot flutes, pumpkin basses, leek violins, eggplant clappers, cucumberophones, celery bongos and numerous other vegetables. The instruments were made by the Vienna Vegetable Orchestra before each performance and were to be cooked in a soup afterwards and served to some members of the audience. (I know that being a musician is a poorly paid profession, but surviving on Rhythm and Gruel is a tough life).
If you think that this article might be a Christmas Con(cert), go to the orchestra’s website and watch their U-Tube video: http://www.gemueseorchester.org/
Happy Christmas, everyone,
John Brooks.
Monday, December 10, 2007
Norovirus spreads fast
We have all read of the mystery illnesses that strike down students in schools and universities and perhaps thought that these outbreaks were caused by overcrowding or poor cleaning in these establishments.
The importance of properly educating food handlers has been emphasized once again. Workers at a Michigan restaurant displayed an almost unbelievable ignorance of simple food handling rules in January last year. (Warning: those with a weak stomach should receive guidance from a food microbiologist before reading further).
Three staff reported for work at the restaurant even though they were suffering intestinal illness. The US Centre for Disease Control and Prevention reports this in a summary of findings of an investigation released two weeks ago. One of the workers vomited into a waste bin before continuing their kitchen duties. They may have believed that using the waste bin was OK, but obviously didn’t think about aerosol generation, transfer of infective particles by their hands and contamination of surfaces in the kitchen and washrooms (or even plain old aesthetics).
The infection turned out to be a Norovirus. These viruses are highly contagious and have an infecting dose as low as 10 particles. The efficiency of infection may be as high as 93% of those people exposed. That’s why we see these outbreaks spread like wildfire through student hostels. The normal transmission pathway is the faecal-oral route, but the particles can survive on surfaces for up to four weeks, so washrooms used by sufferers become very hazardous. The particles can be killed by chlorine (bleach) solutions, but the quaternary ammonium compound used on cleaning cloths in the restaurant was thought to be ineffective.
The CDC recommended that after a vomiting event like this, all exposed food, paper serviettes, takeaway containers and straws should be discarded. All surfaces within an 8-metre radius and all washrooms should be disinfected with a chlorine solution. I would also rewash all crockery and cutlery. It was suggested that restaurant owners should consider briefly closing down for complete cleaning after someone has vomited in the facility. Staff training is critical. Part of the training should be an injunction to stay away from work for at least three days after gastrointestinal illness (and not to handle utensils or ready-to-eat foods for a further three days). Rigorous hand washing and segregation of raw and cooked foods is another obvious precaution.
You can find more information on Norovirus at:
http://www.nzfsa.govt.nz/consumers/food-safety-topics/foodborne-illnesses/
norovirus/factsheetnorovirusv2.htm
The importance of properly educating food handlers has been emphasized once again. Workers at a Michigan restaurant displayed an almost unbelievable ignorance of simple food handling rules in January last year. (Warning: those with a weak stomach should receive guidance from a food microbiologist before reading further).
Three staff reported for work at the restaurant even though they were suffering intestinal illness. The US Centre for Disease Control and Prevention reports this in a summary of findings of an investigation released two weeks ago. One of the workers vomited into a waste bin before continuing their kitchen duties. They may have believed that using the waste bin was OK, but obviously didn’t think about aerosol generation, transfer of infective particles by their hands and contamination of surfaces in the kitchen and washrooms (or even plain old aesthetics).
The infection turned out to be a Norovirus. These viruses are highly contagious and have an infecting dose as low as 10 particles. The efficiency of infection may be as high as 93% of those people exposed. That’s why we see these outbreaks spread like wildfire through student hostels. The normal transmission pathway is the faecal-oral route, but the particles can survive on surfaces for up to four weeks, so washrooms used by sufferers become very hazardous. The particles can be killed by chlorine (bleach) solutions, but the quaternary ammonium compound used on cleaning cloths in the restaurant was thought to be ineffective.
The CDC recommended that after a vomiting event like this, all exposed food, paper serviettes, takeaway containers and straws should be discarded. All surfaces within an 8-metre radius and all washrooms should be disinfected with a chlorine solution. I would also rewash all crockery and cutlery. It was suggested that restaurant owners should consider briefly closing down for complete cleaning after someone has vomited in the facility. Staff training is critical. Part of the training should be an injunction to stay away from work for at least three days after gastrointestinal illness (and not to handle utensils or ready-to-eat foods for a further three days). Rigorous hand washing and segregation of raw and cooked foods is another obvious precaution.
You can find more information on Norovirus at:
http://www.nzfsa.govt.nz/consumers/food-safety-topics/foodborne-illnesses/
norovirus/factsheetnorovirusv2.htm
Wednesday, October 31, 2007
Hand washing not allowed
I hope that all of us in the food industry know just how important hand washing is. If done properly, using hot water and soap, working on all the fingers and paying attention to nails, then rinsing and drying thoroughly, it can significantly reduce the amount of bacterial contamination on the hands. Indeed, there is evidence that clean hand contact with food is far less hazardous than contact from a gloved hand if the operator is not careful about glove use.
Rotavirus infections are highly contagious and commonly affect young children. The main symptoms are watery diarrhoea and vomiting, carrying the risk of dehydration. The outbreaks are often seen in kindergartens and schools. As with all gastrointestinal infections, the main route of infection is directly from improperly washed hands or through contact with contaminated surfaces and toys. The virus is resistant to the environment and to disinfection and will survive on surfaces for a long time, so toilet facilities used by children with watery diarrhoea are obvious transfer points. The time between infection and appearance of symptoms varies from 1 to 3 days.
OK – so what set me off on this lecture? My daughter in law has just had a new baby and we are obviously very aware of the potential for infection during her first few weeks of life. My son, (he’s an engineer but grew up being indoctrinated about food safety) informed me that there is an outbreak of diarrhoea at his children’s school. He has provided the girls with an alcohol hand wash to use at lunchtime, because apparently the children ARE NOT ALLOWED TO WASH BEFORE LUNCH. What kind of education for life is that?
Rotavirus infections are highly contagious and commonly affect young children. The main symptoms are watery diarrhoea and vomiting, carrying the risk of dehydration. The outbreaks are often seen in kindergartens and schools. As with all gastrointestinal infections, the main route of infection is directly from improperly washed hands or through contact with contaminated surfaces and toys. The virus is resistant to the environment and to disinfection and will survive on surfaces for a long time, so toilet facilities used by children with watery diarrhoea are obvious transfer points. The time between infection and appearance of symptoms varies from 1 to 3 days.
OK – so what set me off on this lecture? My daughter in law has just had a new baby and we are obviously very aware of the potential for infection during her first few weeks of life. My son, (he’s an engineer but grew up being indoctrinated about food safety) informed me that there is an outbreak of diarrhoea at his children’s school. He has provided the girls with an alcohol hand wash to use at lunchtime, because apparently the children ARE NOT ALLOWED TO WASH BEFORE LUNCH. What kind of education for life is that?
Wednesday, October 17, 2007
Guaranteed safe (?) At what cost?
You may have read of the shocking toll taken by Escherichia coli O157:H7 in the U.S. and the apparent increasing incidence of the disease. E. coli O157:H7 infection often causes severe bloody diarrhoea and abdominal cramps that may last for 5 to 10 days. In some people, particularly young children and the elderly, the infection can also cause haemolytic uremic syndrome (HUS), in which the red blood cells are destroyed and the debris causes kidneys failure. About 8% of patients may develop HUS. Sometimes the patients recover after a long illness, but a significant number of children have required kidney transplants.
Topps Meat Company, a US company specializing in manufacture of frozen ground beef, initially recalled 330,000 pounds of beef hamburger patties because of E. coli contamination. There had been a number of cases of O157:H7 infection tied to its products. On the 29th September, the company extended the recall to 21.7 million pounds of ground beef, bringing the total recalls in the U.S from April this year to over 30 million pounds of red meat, mostly hamburger. A week later, the company announced that it was going out of business, citing inability “to overcome the reality of a recall this large”.
Clearly, 21.7 million pounds is more than a single day’s production, so there is some sort of systemic failure in the plant. An inability to identify unique batches of product probably contributed to the size of the recall. The USDA also cited the company for “inadequate process controls in the non-ground meat production line”.
The recall highlights the problem of regulations based on product testing. In the US, E. coli O157:H7 is regarded as an adulterant; there is zero tolerance for its presence, so if it is found, the whole product lot must be withdrawn. However, it is extremely difficult to demonstrate total absence of a micro-organism from a product – even with large numbers of samples, it is highly likely that a low-level non-homogeneous contamination would be missed. I am told that the product in question had actually passed two levels of testing and that the recall began only when consumers became ill.
The problem is compounded by the predilection of Americans for consumption of hamburgers cooked rare. Doug Powell at Kansas State University has said many times (and again today) that colour is a poor indicator of sufficient cooking and that consumers should use a meat thermometer. Nobody should be made ill by the food they consume and no company has a right to claim that their small size should exempt them from running properly controlled safe production processes, but consumers must take some responsibility for their own safety. At least one of the consumers who contracted the O157:H7 infection admitted that she had cooked the burgers until they were pink inside.
Raw ground meat is inherently hazardous – it is manufactured from animals that may carry bacteria capable of causing human disease. It is almost impossible to guarantee that some of these bacteria will not be found on the carcase. When the meat is ground, the exterior surfaces and interior tissues are all mixed together, spreading the contamination throughout the meat. (That’s why you can cook a steak rare and produce a beautiful, safe meal, but cooking ground meat rare can leave the pathogens in the centre undamaged and capable of causing illness).
The whole thing is getting out of hand in the US. Companies are recalling huge amounts of food, the authorities are closing processing plants, lawyers are suing for massive damages and consumer advocates are calling for guarantees that food is safe. The result can be only a loss of confidence in the food supply and an increase in costs to the consumer. I see some parallels developing in the case of Campylobacter in poultry in New Zealand
From the industry point of view, the answer lies in greater process control based on a thorough risk analysis, not on discredited end product testing.
Topps Meat Company, a US company specializing in manufacture of frozen ground beef, initially recalled 330,000 pounds of beef hamburger patties because of E. coli contamination. There had been a number of cases of O157:H7 infection tied to its products. On the 29th September, the company extended the recall to 21.7 million pounds of ground beef, bringing the total recalls in the U.S from April this year to over 30 million pounds of red meat, mostly hamburger. A week later, the company announced that it was going out of business, citing inability “to overcome the reality of a recall this large”.
Clearly, 21.7 million pounds is more than a single day’s production, so there is some sort of systemic failure in the plant. An inability to identify unique batches of product probably contributed to the size of the recall. The USDA also cited the company for “inadequate process controls in the non-ground meat production line”.
The recall highlights the problem of regulations based on product testing. In the US, E. coli O157:H7 is regarded as an adulterant; there is zero tolerance for its presence, so if it is found, the whole product lot must be withdrawn. However, it is extremely difficult to demonstrate total absence of a micro-organism from a product – even with large numbers of samples, it is highly likely that a low-level non-homogeneous contamination would be missed. I am told that the product in question had actually passed two levels of testing and that the recall began only when consumers became ill.
The problem is compounded by the predilection of Americans for consumption of hamburgers cooked rare. Doug Powell at Kansas State University has said many times (and again today) that colour is a poor indicator of sufficient cooking and that consumers should use a meat thermometer. Nobody should be made ill by the food they consume and no company has a right to claim that their small size should exempt them from running properly controlled safe production processes, but consumers must take some responsibility for their own safety. At least one of the consumers who contracted the O157:H7 infection admitted that she had cooked the burgers until they were pink inside.
Raw ground meat is inherently hazardous – it is manufactured from animals that may carry bacteria capable of causing human disease. It is almost impossible to guarantee that some of these bacteria will not be found on the carcase. When the meat is ground, the exterior surfaces and interior tissues are all mixed together, spreading the contamination throughout the meat. (That’s why you can cook a steak rare and produce a beautiful, safe meal, but cooking ground meat rare can leave the pathogens in the centre undamaged and capable of causing illness).
The whole thing is getting out of hand in the US. Companies are recalling huge amounts of food, the authorities are closing processing plants, lawyers are suing for massive damages and consumer advocates are calling for guarantees that food is safe. The result can be only a loss of confidence in the food supply and an increase in costs to the consumer. I see some parallels developing in the case of Campylobacter in poultry in New Zealand
From the industry point of view, the answer lies in greater process control based on a thorough risk analysis, not on discredited end product testing.
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