Earlier this year, a serious multi-state outbreak of Escherichia coli O157:H7 infection was associated with consumption of Romaine lettuce from Yuma, Arizona.
The US FDA has now issued an update statement, though the investigation is not completed. Tests of canal water close to the lettuce growing farms has tested positive for the outbreak strain of E. coli O157:H7, which is capable of producing Shigatoxin. Infection with this microorganism can result in serious disease - 210 people in 36 states have become ill, with 96 hospitalizations and five deaths.
No single farm has been determined as the source of the outbreak, nor has the distribution chain been implicated so far.
The lettuce growing farms and canal are close to a Concentrated Animal Feeding Operation (CAFO), which can
hold in excess of 100,000 head of cattle at any one time. Since cattle can harbour the STEC E. coli involved in the outbreak, there is the possibility that the presence of the bacteria in the canal water originated from the CAFO. Further testing of the CAFO and the animals would be necessary to establish a link.
The means by which the lettuces became contaminated must also be investigated. Was the canal water used directly for irrigation, or were the bacteria somehow transferred from the canal water to the leaves?
Showing posts with label STEC. Show all posts
Showing posts with label STEC. Show all posts
Tuesday, August 7, 2018
Tuesday, January 24, 2012
Want to know more about the origin of Shigatoxin-producing E. coli?
Bill Marler is a very rare individual: he is a lawyer with an ability to grasp the principles of microbiological food safety and to write about them in a way that is accessible to the general public. Bill has been closely involved in food borne illness litigation since 1993, when he obtained a $15.6 million settlement for Brianne Kiner, a nine year old girl who suffered HUS and ultimately kidney, liver and pancreas failure after eating Jack-in-the-Box hamburger. He has become a fiercely active food safety campaigner.
Recently, Bill conducted a literature review on the origins of Shigatoxin-producing Escherichia coli and has published the first two parts on his food safety blog. These publications are well worth reading - they are not written in highly technical language, but the reference list allows those readers sufficiently interested and capable to follow up his sources and read the original material.
Links to the first two parts are shown below:
There is just one problem with this review; Bill has taken away my option to set such a study of literature as an assignment for my postgraduate students in my course "Frontiers of Food Microbiology". The students will still be expected to read and discuss the material, but I can't use their reviews for assessment purposes. Thanks Bill!
Recently, Bill conducted a literature review on the origins of Shigatoxin-producing Escherichia coli and has published the first two parts on his food safety blog. These publications are well worth reading - they are not written in highly technical language, but the reference list allows those readers sufficiently interested and capable to follow up his sources and read the original material.
Links to the first two parts are shown below:
There is just one problem with this review; Bill has taken away my option to set such a study of literature as an assignment for my postgraduate students in my course "Frontiers of Food Microbiology". The students will still be expected to read and discuss the material, but I can't use their reviews for assessment purposes. Thanks Bill!
Wednesday, September 14, 2011
Big One becomes Big Seven
Escherichia coli O157:H7 has now been joined on the FSIS most unwanted list by the "Big Six" - other strains of E. coli capable of producing Shigatoxin.
As we saw in May and June 2011 in the German outbreak, Shigatoxin-producing E. coli can cause a potentially deadly food borne infection that can leave survivors damaged for life. The outbreak also resulted in huge economic loss in several European countries as fresh produce was either banned by authorities or shunned by consumers.
As of the 13th September 2011, these seven strains - O157:H7, O26, O11, O103, O121, O45 and O145 - will not be permitted in non-intact raw beef in USA. If they are found to be present, the meat must either be destroyed or cooked before sale.
It has been a long road to get to this point. In October 2009, Bill Marler, a US attorney, filed a petition with USDA/FSIS for an Interpretive Rule declaring all enterohaemorrhagic Shigatoxin-producing serotypes of E. coli, including non-O157 serotypes, to be Adulterants within the meaning of the Federal Meat Inspection Act.
Not much has been heard since, though there has been a certain amount of correspondence. Even the regulatory authorities didn't seem to have a united view. On the 3rd June 2011, the Deputy Director of CFSAN, Donald Kraemer, stated on the FDA website "FDA considers any disease-causing strain of E. coli in food to be illegal”. The FSIS deems only O157:H7 to be an adulterant. Tellingly, Kraemer’s comment was removed from FDA website on 5th July 2011.
The new declaration is being hailed as a victory. Elisabeth Hagen, head of food safety at the Department of Agriculture, said that this was "one of the biggest steps forward in the protection of the beef supply in some time. We’re doing this to prevent illness and to save lives.” A worthy cause.
However, I have some concerns about this optimism. Will the reclassification of the Big Six make meat safer? I'm not so sure. Certainly, if these bacteria are detected in meat, the product will not be allowed on the market unless it is diverted to cooked products. This may be a challenge for the meat processors - since 1994, O157:H7 in raw ground beef has been declared an adulterant with zero tolerance by FSIS. In October 2007, the Topps Meat Company recalled 21.7 million pounds of ground beef, bringing the total recalls in the US between April and October 2007 to over 30 million pounds of red meat, mostly hamburger. A company manufacturing frozen hamburger patties is unlikely to have the capacity to redirect this much meat to a cooking process and there may be difficulties in finding a buyer for the product, so it may have to be destroyed.
Secondly, as far as I am aware, there is no requirement for processors to test for these bacteria. If this situation doesn't change, the first indication that something is wrong may still be when people start showing up at the hospital with gastrointestinal disease.
Thirdly, the cost of testing is currently very high and the testing may take up to 5 days, even when things go well. I have already written about the impossibility of guaranteeing safe food by testing.
Finally, testing for the Big Seven will miss any Shigatoxin-producing non-members, as was the case with the German outbreak of O104:H4
The FSIS move is a good start and is motivated by good reasons. However, the only way that safety of food can be improved is by development of risk management plans and rigorous application of critical control points throughout the food chain, including food service outlets, i.e. farm to fork. Consumers should not receive contaminated food, but they too must play their part by prevention of cross contamination in the home and proper cooking of foods. Future posts will deal with some of these approaches.
Where does that leave us with foods like sprouts? Food for thought.
Since I wrote this article, Shawn Stevens has written an article "Big six declared Adulterants: Is it a good thing?" in Meatingplace.com, a blog for the meat industry in the US. It seems that he too has some concerns. You may have to register to read the article, but registration is free.
As we saw in May and June 2011 in the German outbreak, Shigatoxin-producing E. coli can cause a potentially deadly food borne infection that can leave survivors damaged for life. The outbreak also resulted in huge economic loss in several European countries as fresh produce was either banned by authorities or shunned by consumers.
As of the 13th September 2011, these seven strains - O157:H7, O26, O11, O103, O121, O45 and O145 - will not be permitted in non-intact raw beef in USA. If they are found to be present, the meat must either be destroyed or cooked before sale.
It has been a long road to get to this point. In October 2009, Bill Marler, a US attorney, filed a petition with USDA/FSIS for an Interpretive Rule declaring all enterohaemorrhagic Shigatoxin-producing serotypes of E. coli, including non-O157 serotypes, to be Adulterants within the meaning of the Federal Meat Inspection Act.
Not much has been heard since, though there has been a certain amount of correspondence. Even the regulatory authorities didn't seem to have a united view. On the 3rd June 2011, the Deputy Director of CFSAN, Donald Kraemer, stated on the FDA website "FDA considers any disease-causing strain of E. coli in food to be illegal”. The FSIS deems only O157:H7 to be an adulterant. Tellingly, Kraemer’s comment was removed from FDA website on 5th July 2011.
The new declaration is being hailed as a victory. Elisabeth Hagen, head of food safety at the Department of Agriculture, said that this was "one of the biggest steps forward in the protection of the beef supply in some time. We’re doing this to prevent illness and to save lives.” A worthy cause.
However, I have some concerns about this optimism. Will the reclassification of the Big Six make meat safer? I'm not so sure. Certainly, if these bacteria are detected in meat, the product will not be allowed on the market unless it is diverted to cooked products. This may be a challenge for the meat processors - since 1994, O157:H7 in raw ground beef has been declared an adulterant with zero tolerance by FSIS. In October 2007, the Topps Meat Company recalled 21.7 million pounds of ground beef, bringing the total recalls in the US between April and October 2007 to over 30 million pounds of red meat, mostly hamburger. A company manufacturing frozen hamburger patties is unlikely to have the capacity to redirect this much meat to a cooking process and there may be difficulties in finding a buyer for the product, so it may have to be destroyed.
Secondly, as far as I am aware, there is no requirement for processors to test for these bacteria. If this situation doesn't change, the first indication that something is wrong may still be when people start showing up at the hospital with gastrointestinal disease.
Thirdly, the cost of testing is currently very high and the testing may take up to 5 days, even when things go well. I have already written about the impossibility of guaranteeing safe food by testing.
Finally, testing for the Big Seven will miss any Shigatoxin-producing non-members, as was the case with the German outbreak of O104:H4
The FSIS move is a good start and is motivated by good reasons. However, the only way that safety of food can be improved is by development of risk management plans and rigorous application of critical control points throughout the food chain, including food service outlets, i.e. farm to fork. Consumers should not receive contaminated food, but they too must play their part by prevention of cross contamination in the home and proper cooking of foods. Future posts will deal with some of these approaches.
Where does that leave us with foods like sprouts? Food for thought.
Since I wrote this article, Shawn Stevens has written an article "Big six declared Adulterants: Is it a good thing?" in Meatingplace.com, a blog for the meat industry in the US. It seems that he too has some concerns. You may have to register to read the article, but registration is free.
Tuesday, August 9, 2011
Haemolytic Uraemic Syndrome
In the wake of infection by Shigatoxin producing Escherichia coli (STEC), some patients develop Haemolytic Uraemic Syndrome (HUS). The recent outbreak of O104:H4 STEC in Europe resulted in an unusually high proportion of patients going on to develop the syndrome, some of whom succumbed to the infection.
Drew Falkenstein, an associate of Marler Clark law firm in Seattle, has written a very well informed article on HUS. Rather than write another, I suggest that interested readers follow the link to Drew's posting on Food Poison Journal.
Drew Falkenstein, an associate of Marler Clark law firm in Seattle, has written a very well informed article on HUS. Rather than write another, I suggest that interested readers follow the link to Drew's posting on Food Poison Journal.
Friday, June 3, 2011
How do you trace an outbreak? With difficulty!
The outbreak of E. coli O104:H4 food poisoning in Germany is possibly one of the worst outbreaks on record and certainly one of the most deadly.
Public health officials still don't know the source. Spanish cucumbers were initially blamed, but it appears that might have been wrong, though it does appear that salad vegetables may have been involved.
The investigation of outbreaks like this is a science in itself, but must be frustrating for epidemiologists. Our modern supply chains are extremely complex - foods are sourced from all over the world and suppliers may make up orders from many different primary producers.
"...real life does not have tidy TV endings. Despite determined efforts and great expense, the precise source of poisoning is found in fewer than one-third of outbreaks. But here is a quick look at how public officials try to resolve those puzzles.
First, there is a trigger event – usually people showing up in emergency rooms with violent cases of diarrhea and vomiting that are the hallmarks of food poisoning. Samples – stool, saliva, sometimes blood – are taken. Serious illnesses like E. coli get special attention:
Reporting them to public health authorities is mandatory.
Data from lab tests are routinely sent to local public health authorities and to PulseNet, an electronic database. While most cases of food poisoning are sporadic, patterns can be spotted quickly – there can be a cluster in a single city, or a sudden spike over a wide geographic area. Labs do DNA fingerprinting of pathogens like E. coli that can show if the illnesses have a common source.
In this instance, three deaths of patients with E. coli infection in Germany set off alarm bells. They all had the same DNA fingerprint, strongly suggesting a common food source.
When an outbreak is suspected, epidemiologists (disease detectives) start questioning those who are sick. In these “hypothesis-generating” interviews, patients are asked about specific high-risk foods (such as sprouts or unpasteurized milk) and for detailed recollections of what they have eaten in recent weeks.
This can produce, fairly quickly, a list of suspected culprits. E. coli is a fecal bacterium, for example, so raw foods are a focus. In Germany, a day after the deaths, consumers were warned to not eat tomatoes, cucumbers or lettuce. Three of four cucumbers tested came from Spain, so the country was quickly identified as a culprit in media reports.
Public health officials share information gathered from patients with food safety regulators (such as the Canadian Food Inspection Agency), who try to trace the commercial supplier of a common food source.
In their interviews, epidemiologist collect information on where food is purchased; if many of the patients shopped at the same food chain, for example, the CFIA would identify their vegetable suppliers and try and trace the movement of food through distributors and back to the farm.
But there can be hundreds, even thousands, of suppliers and contamination of food can occur at any point in the process of getting food from the farm to the table – during production, processing, storage, distribution or preparation. Finding the “locus of contamination” becomes an almost insurmountable process of elimination. Currently, farms in Europe that produce vegetables that are consumed raw are being set upon by all manner of investigators who will test products, water sources and so on.
The paradox is that the more people get sick, the easier it is to ultimately find the culprit because the number of food sources they have in common becomes smaller. Often, despite mountains of data, the leads run cold. But the demand for answers does not wane.
The challenge for public health officials and regulators is finding the right balance. They issue speculative warnings like “Don’t eat Spanish cucumbers,” but more often than not they are wrong, and that can cause grievous damage to food producers.
At the same time, acting slowly and waiting for a definitive answer on the source can result in countless cases of illness and death, and still no definitive answer.
To read the full article and access the video clips, click here.
Not all reporting is of this quality; even the BBC has broadcast a news item labeling E. coli as "a virus". Didn't the reporter talk to an expert, or even a Level 6 food science student?
Public health officials still don't know the source. Spanish cucumbers were initially blamed, but it appears that might have been wrong, though it does appear that salad vegetables may have been involved.
The investigation of outbreaks like this is a science in itself, but must be frustrating for epidemiologists. Our modern supply chains are extremely complex - foods are sourced from all over the world and suppliers may make up orders from many different primary producers.
André Picard, — Public Health Reporter of Canadian newspaper "The Globe and Mail" wrote a neat article with associated links and videos on the investigative process and its difficulties. I have reproduced part of it below:
"...real life does not have tidy TV endings. Despite determined efforts and great expense, the precise source of poisoning is found in fewer than one-third of outbreaks. But here is a quick look at how public officials try to resolve those puzzles.
First, there is a trigger event – usually people showing up in emergency rooms with violent cases of diarrhea and vomiting that are the hallmarks of food poisoning. Samples – stool, saliva, sometimes blood – are taken. Serious illnesses like E. coli get special attention:
Reporting them to public health authorities is mandatory.
Data from lab tests are routinely sent to local public health authorities and to PulseNet, an electronic database. While most cases of food poisoning are sporadic, patterns can be spotted quickly – there can be a cluster in a single city, or a sudden spike over a wide geographic area. Labs do DNA fingerprinting of pathogens like E. coli that can show if the illnesses have a common source.
In this instance, three deaths of patients with E. coli infection in Germany set off alarm bells. They all had the same DNA fingerprint, strongly suggesting a common food source.
When an outbreak is suspected, epidemiologists (disease detectives) start questioning those who are sick. In these “hypothesis-generating” interviews, patients are asked about specific high-risk foods (such as sprouts or unpasteurized milk) and for detailed recollections of what they have eaten in recent weeks.
This can produce, fairly quickly, a list of suspected culprits. E. coli is a fecal bacterium, for example, so raw foods are a focus. In Germany, a day after the deaths, consumers were warned to not eat tomatoes, cucumbers or lettuce. Three of four cucumbers tested came from Spain, so the country was quickly identified as a culprit in media reports.
Public health officials share information gathered from patients with food safety regulators (such as the Canadian Food Inspection Agency), who try to trace the commercial supplier of a common food source.
In their interviews, epidemiologist collect information on where food is purchased; if many of the patients shopped at the same food chain, for example, the CFIA would identify their vegetable suppliers and try and trace the movement of food through distributors and back to the farm.
But there can be hundreds, even thousands, of suppliers and contamination of food can occur at any point in the process of getting food from the farm to the table – during production, processing, storage, distribution or preparation. Finding the “locus of contamination” becomes an almost insurmountable process of elimination. Currently, farms in Europe that produce vegetables that are consumed raw are being set upon by all manner of investigators who will test products, water sources and so on.
The paradox is that the more people get sick, the easier it is to ultimately find the culprit because the number of food sources they have in common becomes smaller. Often, despite mountains of data, the leads run cold. But the demand for answers does not wane.
The challenge for public health officials and regulators is finding the right balance. They issue speculative warnings like “Don’t eat Spanish cucumbers,” but more often than not they are wrong, and that can cause grievous damage to food producers.
At the same time, acting slowly and waiting for a definitive answer on the source can result in countless cases of illness and death, and still no definitive answer.
To read the full article and access the video clips, click here.
Not all reporting is of this quality; even the BBC has broadcast a news item labeling E. coli as "a virus". Didn't the reporter talk to an expert, or even a Level 6 food science student?
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