【Food Safety News】专题研究：美国食品安全历史（续）

Part 3: History of Food Safety in the U.S.

Why do we hear more about food safety issues today than in the past? Are these issues something we really need to worry about or just a bunch of media hype? What incredibly difficult questions to answer. Let me start by saying there is no “final answer,” only mere suggestions, theories and probable correlations. Here are some of the probable answers:

One of the main reasons we are more aware of food safety issues and foodborne illness is the fact that science has advanced. As little as 50 years ago, we didn’t have the technology necessary to detect some microbes that had existed for centuries. Many illness-causing microbes, such as Campylobacter jejuni, weren’t linked to human illness or identified as a foodborne pathogen until the 1970s or later.

Better microscopes, more thorough testing procedures, and more testing in general has made us a society that is more aware of the microbiology around us. Only recently have we acquired the capability to gather samples from sick people around the globe, test potential contaminated foods, match those two samples to find the culprit of the illness, and then track the food back to where it came from — all of this in less than 24 hours. Fifty years ago, it may have taken weeks to link multiple illnesses in the same state, if it happened at all, and the incidents most likely never made the news unless numerous people died from the outbreak. (Note: Reading this may sound like an easy process, which it is not, but it is possible in some cases. Such advances in science have led to food recalls which hit the media and spark local, national and even global awareness.)

Another reason there is generally more awareness surrounding food safety is that microbes are constantly changing, and many “old” microbes are resurfacing in new and surprising places.

Vibrio cholerae, better known as cholera, hadn’t been found in the Americas for more than 100 years, but it was suddenly showing up again in the early 1990s. Traditionally thought of as a disease of countries with poor sanitation, cases were showing up in the U.S. and were eventually linked to contaminated imported foods. Now, global food chains and the demand for fresh fruit and vegetables year-round (like strawberries in December) are potentially bringing pathogens to a grocery store near you. Older microbes are also mutating into more virulent strains, some of them antibiotic-resistant. One such example is Salmonella, which we have experienced the perils of for centuries (typhoid fever), but newer, resistant strains, such as Salmonella typhimurium DT104, are surfacing regularly. Some speculate that overuse of antibiotics in food animals, as well as humans, may be contributing to these new resistant forms of old bacteria, but the jury is still out. These disease agents, along with several others, were presented in a 2013 Food Safety Progress Report.

Cultural shifts in the way we interact with the environment around us, as well as changing the ways in which we raise our food, may also contribute to raised incidence and awareness of foodborne illness. A good example of this is E. coli. We have been living with E. coli since the beginning of time. Some strains are already present inside our bodies and don’t cause us harm, but other strains, such as O157:H7, can be deadly. This strain is most often found in the fecal matter of cows and has been linked to several illness outbreaks from hamburgers. Most of the ground meat in the U.S. comes from concentrated animal farms, where cattle are kept in large numbers in close quarters where the bacteria can be spread easily between cattle, and through manure on the bodies of cattle going to slaughter. Once in the slaughterhouse, the bacteria from one infected cow could potentially contaminate thousands of pounds of ground meat as it is all mixed together in large batches.

Although strains very similar to E. coli O157:H7 have been around for 50,000 years, strains were only identified as a pathogen in humans in 1982. Why did it all of a sudden make a dramatic appearance? One suggestion is that, as a society, we used to live in close proximity to cattle and thus were a part of the environment that contained such microbes and our immune systems were accustomed to them. Whereas now, we are mostly very separate from the farm animals we eat and have not evolved with a shared set of microbes. Another suggestion involves changes in farming practices. Cattle are traditionally herbivores, grass-eaters to be exact, but the fattening of cows for slaughter is more easily and cheaply done with grain and other food additives. Some science suggests that this change in diet could have led to E. coli adapting to stomach acid levels that would allow it to thrive in human guts.

Furthermore, instead of a very clear path of meat from the farm to your fork, a complicated corporate, maze-like chain of supply gets the meat from the farm to your fork, so that now, in a one-pound package of burger, we could possibly be ingesting meat from more than 100 different cows, from multiple locations, possibly even other countries. With ever-increasing demand for inexpensive meat, there come more cattle, and more manure, and less space to put all of it. For those reasons, it is no wonder that E. coli O157:H7 is also showing up in unconventional places such as deer and seagulls, who may have been exposed to raw manure or water contaminated with manure.

There have also been major shifts in our own eating culture. Americans today are always on the go and too busy to cook at home, let alone grow their own food. We are a culture of convenience. Most Americans have no idea where their food comes from, and most first-graders can’t tell a tomato from a potato. We have completely disconnected from our food. Instead, we rely on pre-packaged, pre-sliced, pre-cooked “food,” or, we go out to eat. Studies show that Americans now eat out four times per week on average. By doing so, we are putting the job of preparing our food in the hands of some of the lowest-paid people in the country who almost never get paid sick days. A 2007 study found that many food-handlers are generally aware of germs, but they don’t truly understand their role in prevention. Other studies conclude that about 50 percent or more of food workers go to work when sick because they can’t afford to take a day off. Currently, about 20 percent of foodborne illness outbreaks can be traced to a sick food worker. The concept of “cooked” has also changed in the past 50 years. In the past, a pink or rare burger at a restaurant (or at home) was unheard of, but today most places cook burgers to “medium” unless otherwise stated. Unfortunately, most people don’t realize that consuming a burger cooked to anything less than 160 degrees F puts you at risk of ingesting dangerous microbes.

As you can see, the subject is vast, and it’s really difficult to pinpoint one single reason for increasing outbreaks and awareness. I’ve only touched on a few here, yet there are others that blame media hype, overuse of antibiotics in the medical industry, and a society that is fearful and thus elbow-deep in antibiotic hand gels that may hurt more than help. No matter what the reasons, microbes are here to stay. Michigan State University Extension recommends the best way to protect yourself from foodborne illness is to wash your hands thoroughly before handling food and thoroughly cook meats to the recommended internal temperatures for the type of meat being cooked.