13,000 beef animals just went to the landfill

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.

Is food less safe these days? Part 1

Over the Christmas period I have done a lot of eating and drinking and being merry. I’ve also done a lot of thinking about food safety. In the last year we seem to have read almost daily of Listeria being found in deli meat, that babies have been poisoned by formula milk, children have been hospitalized with failing kidneys resulting from Escherichia coli O157:H7 infection, that melamine has turned up in yet another food product, or that an established company has closed its doors because of massive losses resulting from a food recall. Is our food less safe these days?

I don’t think that there is a simple answer, but I do have some suggestions. In this three-part posting I’ll share them with you.

I think that the whole thing can be analysed under a few subheadings.

Food Preparation: Some of my Christmas celebrations have involved large functions where caterers have served meals to hundreds of partygoers. These meals could not have been produced on the premises, so the food must have been pre-prepared and transported to the venue in insulated containers or perhaps reheated before serving. Other celebrations have been more modest, catered by the “bring a plate” approach. We have had barbecues, where foods were cooked outside on gas or charcoal burners. All of these scenarios have at least one thing in common – the foods were prepared by others for us, perhaps in non-ideal conditions, or were not eaten immediately after preparation. The opportunities for contamination of the food, incomplete cooking and growth of bacteria were numerous.

Centralization: The economies of scale lead to evolution of very large manufacturing operations with huge distribution networks. Smaller companies are squeezed out of the market. If something goes wrong in this supply chain, the impact can be widespread. In 2000, Staphylococcus aureus bacteria built up in raw milk that was unable to be cooled for several hours after fat separation in Snow Brand's Taiki factory. Ultimately, at least 14,700 people, mostly in western Japan, were affected by food poisoning after consuming milk or related products made by the company. Topps Meat Company, a US company specializing in manufacture of frozen ground beef, 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. The reason was that there had been a number of cases of Escherichia coli O157:H7 infection tied to its products. There was evidence of an inability to identify unique batches of product and this 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”.

Ignorance may play a part. Last Easter in New Zealand, 22 people were poisoned, some seriously, when they consumed comb honey which had been made by bees that collected honeydew from tutu plants (Coriaria arborea) infested by vine hoppers. The upshot was that the honey contained large amounts of the toxin tutin, which is found in the sap of the tutu plant. In April last year, I wrote that this was not a new problem. See here Indeed, F.S. Fastier, Roslyn Emeritus Professor of Pharmacology at University of Otago, wrote last week that he was present at a meeting of interested parties in Wellington in 1964, where the issue was debated. Beekeepers have known how to manage this hazard for a long time, but a small beekeeping operator last year apparently failed to take account of the fact that there were tutu bushes in flower in the bees’ foraging area and continued to sell the comb honey. The resulting poisonings have led to the New Zealand Food Safety Authority introducing legislation to limit the amount of tutin that may be present in honey offered for sale. See here
This has not pleased everyone – some think the regulations don’t go far enough, some in the industry consider them to be unnecessary. However, NZFSA could not stand by and do nothing without risking the health of the population and the future of the lucrative New Zealand honey industry. The regulations will be reviewed at the end of the 2009 season.


In Part 2: click here:  Globalization and Greed

Is hamburger a greater risk for E. coli?

The subject of coliforms in food and specifically the question about hamburger comes up often in the referrals to this blog.

Coliforms are used in the food industry as indicators of general hygiene. This sounds simple, but it is not quite straightforward; we need to understand what coliforms are and how they are measured before we can draw conclusions.

The term “coliform” does not refer to a unique species. In fact, coliforms are a group of bacteria defined by the test used to detect them. Thus, we can carry out a simple culture test that will count or show the presence or absence of this group. Each country uses slightly different tests. One protocol defines coliforms as:

“Gram negative rods that produce acid and gas from lactose in the presence of bile salts at 37 C in 24 to 48 hours”

Notice that there is no mention of genus or species or connection with faecal contamination. In fact, the group includes several genera that are capable of growing in the environment and have no faecal connotation, so finding coliforms on lettuces should not be cause for undue concern. What we can say is that all of these bacteria should be killed by pasteurization temperatures, so if they are found in pasteurized foods, the hygiene of the process has been poor.

If we want to show that faecal contamination of food has occurred, we do a test for Escherichia coli, which is found at high concentration in faeces. This test for “faecal coliforms” was originally used to test water, where the organism cannot grow. The situation in food is a little more complicated because the organisms may grow in the food, but the finding of E. coli in food is good evidence of faecal contamination. Properly pasteurized food should not contain any faecal coliforms. Raw foods, such as leafy vegetables, can become contaminated by faecal coliforms if birds or animals have access to the crops. This was the probable cause of E. coli O157:H7 contamination of raw spinach last year.

Meat animals all have E. coli in their intestines and there is a possibility of contamination of the carcase by spillage of gut contents during slaughtering. This contamination will initially be on the meat surface, but will be distributed throughout the meat if it is minced or ground. This is why steak can be eaten “rare”, since the interior of meat from healthy animals is sterile – all that is required is for the exterior to be cooked to a temperature of about 70 – 75 C. However, hamburger patties are made from ground meat and must therefore be cooked right through to ensure destruction of faecal bacteria that may have been mixed in. Americans tend to eat hamburger cooked less thoroughly than in other countries. The USDA suggests 71.1 C (160 F) for beef burgers. So the real issue is not that hamburgers are at greater risk of contamination, but that undercooking them may allow E. coli to survive.
See Guaranteed safe At what cost (?) October 17, 2007
http://foodsafetywithjaybee.blogspot.com/2007/10/
guaranteed-safe-at-what-cost.html

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.