Next time you chow down on that juicy burger grilled on your trusty barby or when ordering your fave from a local drive-thru, better make sure that burger is well-done — really well done.
For decades, Health Canada advised consumers to cook ground beef to 71 °C (159.8 °F) — supposedly the tipping point for harmful bacteria, like E coli, to be thermally destroyed making the ground beef safe to eat. But food scientists at the University of Alberta recently discovered the recommended temperature may not be high enough.
For years, scientific papers about micro-organisms in meat have repeatedly stated, that sometimes not all the micro-organisms are destroyed during the cooking process. There can be survivors. That’s significant because while not all E. coli are harmful, nasty strains such as E. coli O157 can be lethal to humans.
“We’ve been hammering consumers for years to cook chicken properly, to handle it properly, and to do the same with ground beef. But still we seem to have these outbreaks of E. coli [attributed to hamburgers],” Lynn McMullen, a food microbiologist in the Department of Agricultural, Food and Nutritional Science stated.
So back in 2008, her department decided to create a long term food study to find out what was going on. Long term studies are seldom carried out in the food industry because they tend to be very costly. In fact, it’s one of the reasons kingpins in industrial agriculture avoid independent long-term studies. Behemoths like Monsanto, Dow and the other GMO seed giants, whose profits are in the billions annually, claim these studies are too costly to carry out. To get around any sticky transparency issues, they and our regulators, hide behind a food safety policy that was created in the early 90s at the beginning of the GMO onslaught. The policy maintains that the safety of a new food, particularly one that has been genetically modified (GMO), can be assessed by comparing it to a similar traditional food that has proven safe in normal use over time. Substantial equivalence is the underlying principle in GMO food safety assessment for a number of national and international agencies, including the Canadian Food Inspection Agency.
However, the Food and Nutritional Science program at University of Alberta (UA) were blessed. The University houses cattle in support of other programs, so the Department had access to a diverse feed-cattle population.
What the researchers discovered was a shocker. The E. coli bacterium tested were displaying inconsistent behaviour. One organism survived a full 70 minutes at 60 degrees Celsius. That temperature should have snuffed out the questionable bacteria in seconds. It didn’t.
Not quite believing what they were seeing, the team, headed by Professors Lynn McMullen and Michael Gänzle, repeated the experiments twice. Both test scenarios produced identical results. Then they compared their results of survival values to other labs and discovered that other cultures behaved differently too.
So what’s the big deal? Escherichia coli, (E coli) is a bacterium found in the gut of both humans and some feed animals, like cattle. Bovines share 80 percent of their genes with humans so the bacteria found in beef can cross the animal/human gene barrier potentially causing some serious damage to the human body. The concern is very real. While some E coli strains are harmless, others can cause kidney failure and death.
The results, according to McMullen, demonstrate that the standard temperature may not be sufficient to eliminate all the strains of E. coli and that may explain the persistence of outbreaks related to ground beef. In other words, cooking ground beef to 71 °C does not always eliminate all strains of E coli.
“These organisms aren’t supposed to survive, but every once in a while they do,” said McMullen. “So we decided to find out why. We looked at the genomes to see what was different.”
Working with post-doctoral fellow Ryan Mercer, they discovered a suite of 16 genes found only in the highly heat-resistant strains of E. coli under wet conditions (such as in fresh meat). This genomic grouping is called the locus of heat resistance, or LHR. Hunting through the genome databases for LHR, they discovered it exists in about two per cent of all E. coli in the databases in both the harmless and pathogenic strains.
The team is working with Health Canada with support from the Alberta Livestock and Meat Agency, to determine how often pathogenic E. coli will survive in cooked meat. Meanwhile, if you are a beef eater, make sure it’s well done.