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.