To compensate for this inherent uncertainty, food safety officials often base their policies on the so-called worst-case scenario. They reason that if you assume the absolute worst contamination levels and act to address that threat, then the public will always be safe. Setting relatively high D levels to account for a worst-case scenario establishes such a formidable barrier for pathogens that even highly contaminated food will be rendered safe. High D levels also offer a measure of insurance against an imperfect thermometer, an unevenly heated oven, an inaccurate timer, or an impatient chef. If real-world conditions miss the mark, slightly lower reductions will still suffice.
Not surprisingly, some food safety experts challenge this conservative approach. The required pathogen reductions or “drops” explicitly cited in U.S. federal regulations, for example, range from
a 4D drop for some extended-shelf-life refrigerated foods, such as cooked, uncured meat and poultry products, to a 12D drop for canned food, which must last for years on the shelf. General FDA cooking recommendations for fresh food are set to reach a reduction level of 6.5D, which corresponds to killing 99.99997 percent of the pathogens present. Many nongovernmental food safety experts believe this level is too conservative and instead consider 5D to 6D pathogen reduction for fresh foods sufficient for real-world scenarios.
An expert advisory panel charged with reviewing the scientific basis of food safety regulations in the United States made just this point about standards developed by the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS). In a 2003 report, the panel, assembled by the U.S. Institute of Medicine and National Research Council, questioned the FSIS Salmonella reduction standards for ready-to-eat poultry and beef products. In devising its standards, the FSIS had established a worst-case Salmonella population for the precooked meat of each animal species, then calculated the probability that the pathogen would survive in 100 grams / 3.5 ounces of the final ready-to-eat product.
In the case of poultry, for example, the FSIS calculated a worst-case scenario of 37,500 Salmonella bacteria per gram of raw meat. For the 143 grams / 5 ounces of starting product necessary to yield 100 grams / 3.5 ounces of the final, ready-to-eat product, that works out to nearly 5.4 million Salmonella bacteria before cooking. To protect consumers adequately, the FSIS recommended a 7D drop in bacterial levels, equivalent to a reduction from 10 million pathogens to one.
The review committee, however, found fault with several FSIS estimates that, it said, resulted in an “excessively conservative performance standard.”Even “using the highly improbable FSIS worst-case figure,” the committee concluded that the ready-to-eat regulation should instead require only a 4.5D reduction.
The irony is that, although experts debate these matters, their rigorous analyses can be undermined by confounding factors such as cross-contamination. Imagine, for example, that a highly contaminated bunch of spinach really does require a 6.5D reduction in pathogens to be safe. Even if that spinach is properly cooked, it could have contaminated other food or utensils in the kitchen while it was still raw, rendering moot even an extreme 12D reduction during the cooking process. A chain is only as strong as the weakest link, and in food safety, cross-contamination is often the weakest link. One powerful criticism of food safety standards is that they protect against unlikely worst-case scenarios yet do not address the more likely event of cross-contamination.
Another conservative tactic used by health officials is to artificially raise the low end of
a recommended temperature range. Most food pathogens can be killed at temperatures above 50 degrees C / 120 degrees F , yet food safety rules tend to require temperatures much higher than that. Experts may worry that relying on the low end of the range may be dangerous for the same reasons that moderate D levels cannot be trusted: vacillating oven temperatures, varying chef temperaments, and so on. Still, their solution belies the facts.
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9 Comments
Add CommentWell that explains why the time i accidentally cooked my pork roast to the internal temperature of rare/medium rare beef (140 F) it was so good !
Reply | Report Abuse | Link to thisFantastic article - thanks.
Reply | Report Abuse | Link to thisPersonally, I love a rare hamburger (red, not pink). And I'm frustrated by the refusal of most restaraunts to cook it that way. Generally, even if they say they cook to order and will cook it rare, it comes out medium or worse.
I even had a T bone steak recently which I ordered rare come out more like medium. Nothing unusual there, except the cook claimed that the local health inspector was requiring that steaks need to be cooked to 125 internal temperature!
I believe that these over-cautious public health recommendations are also applied to handling pets. This in turn causes some people to consider pets necessarily "dirty". This is untrue for well cared for pets [there should be no other standards really]. Thus many people who own pets are at a disadvantage in many parts of their lives such as finding housing and in court disputes.
Reply | Report Abuse | Link to thisAs the authors point out in the book, it's important to keep in mind that ground meat (or meat tenderized by puncturing) is more susceptible to contamination because external surfaces are mixed into the interior of the food. Any bacteria that get onto the outside of the meat during handling can thus be spread throughout the meat, which doesn't happen in intact muscle meats like well-butchered steaks.
Reply | Report Abuse | Link to thisIt is thus riskier to eat ground beef that is rare, and if you don't have complete confidence in the hygiene of the butchering and handling that went into the preparation of the ground meat, the safest course is to cook the meat longer or to a higher temperature.
I plan to grill a steak for dinner tonight. Seared on the outside and running red when cut. If it don't bleed it's burnt! As for pork, pink inside running clear juices on the plate is just fine. I also prefer limp bacon. Runny eggs go great with it. Sushi is also a part of my diet. If Big Brother doesn't like it, he can shove it.
Reply | Report Abuse | Link to thisBig Brother isn't forcing your hand in your own kitchen. You are free to take your own risks there, this article discuses regulations for food manufacturers and restaurants.
Reply | Report Abuse | Link to thisWhile I agree that many of the regulations are arbitrarily assigned and influenced by factors other than safety, I can't help but think that I'd rather not risk a food-borne illness (especially for someone who's immunocompromised) just for the sake of a slightly more delicious pork chop.
Reply | Report Abuse | Link to thisI'd rather be overcooking food than risking undercooking (due to faulty thermometers, cooks who don't know any better, etc.) because the food safety guidelines are right on the cusp of safety.
I think the bigger issue is how food manufacturers may be taking advantage of these extreme cooking guidelines to be more slack with their microbial control. If they know it'll be cooked to a 12D level of destruction, what's the incentive to use good manufacturing processes?
I am grateful that this article is here because I too love a rare steak, carpaccio, and sushi, but as wayt pointed out, ground beef is an exception.
Reply | Report Abuse | Link to thisGround beef is probably not safe unless you see it ground for yourself by a butcher you trust. Any given pound of commercially-produced ground beef can and does contain pathogens from literally thousands of cows, usually dairy cattle worn out by several years of filthy conditions, rBGH, antibiotics, and chronic low-level infection. To that, add scrap meat from all over the country, and grind. It's a food safety nightmare.
Because of this the meat packing industry has (once again!) started to use ammonia gas to "disinfect" ground beef, a practice exposed by Upton Sinclair's The Jungle, which detailed the horrific conditions for humans, animals, and our food in the meatpacking industry of the time. Legislation ensued, and for perhaps 50 years we had reasonable standards for meatpackers. This has since been undone, and now we're back (once again!) to having immigrants paid in dirt perform this work, on lines whose speed has been increased again and again, rendering it impossible for even the most conscientious gutter to ensure that there isn't shit in the meat. We're right back where we were at the start of the 20th Century in terms of labor and animal abuse, and right back where we were in terms of food safety.
I encourage all readers to purchase their meat from smaller, more local vendors -- the reward in taste, nutrition (e.g. grass-fed meat), and safety is more than worth it. If you are reading this article to begin with, you are likely to notice and appreciate the difference!
Readers of this article might be interested in my response to this excerpt posted here: http://barfblog.foodsafety.ksu.edu/blog/147413/11/03/27/more-modernist-cuisine-and-bad-microbial-food-safety-colbert-careful-clostridiu
Reply | Report Abuse | Link to thisIn short, while I agree that some standards today are inconsistent, the authors do make some microbiological errors that would lead to food safety problems.