spea magazine

Just Curious: Q&A

Beefing Up Food Safety

Dave McSwane offers some rare insights.

dave mcswaneIs “mad cow disease” going to be a threat in the U.S. anytime soon?
I really don’t think so. The USDA and other organizations are creating a system that will assure protection of our food supply against Bovine Spongiform Ecephalopathy (BSE) or what is commonly referred to as “mad cow disease.” There is a disease similar to BSE called Creutzfeldt-Jacob Disease (CJD) found in humans, and a variant form of CJD (vCJD) is believed to be caused by eating contaminated beef products from BSE-affected cattle. According to the FDA, there have been 155 confirmed or probable cases of vCJD worldwide. To date, we’ve identified only two cows in the U.S. with BSE.

The public’s perception of risk is attributed at least in part to the media coverage of this issue, but there are other food safety issues that should be more on their minds than mad cow at this point. I do think that the USDA has certainly taken the necessary steps to enhance their regulatory oversight with the tracking of animals and safeguards that should, with a high degree of effectiveness, protect Americans from mad cow disease.

Should we be worried about food coming from areas affected by the recent hurricanes?
Probably not, mainly because there isn’t much food coming out of those regions due to the devastation. The more fundamental issue is that we do have safeguards in place to ensure the safety of the American food supply. The real key is to always buy food from approved sources. These would be sources that are routinely inspected and under the jurisdiction of either a federal or state food or public health agency. The bottom line is if you buy your food from approved sources, you should be able to minimize your risk significantly.

So what should we be worried about?
There are many other pathogens that we need to be concerned about. In terms of causing disease, there are things like the E. coli organism that can cause a variety of symptoms and in some cases, very severe health problems for children. Listeria monocytogenes is another pathogen that has emerged on the scene in the last few years that is dangerous for children and in some cases, has been shown to cause stillbirths when it’s consumed by pregnant women.

Historically, food scientists and public health professionals have considered pathogenic bacteria as the most common cause of food-borne illness. This is largely due to the fact that it’s easier to isolate and study these bacteria. However, in recent years we have improved our techniques for detecting and studying viruses. We now believe viruses such as hepatitis A and noroviruses are as important, and in many cases more important, than bacteria as causes of food-borne illness.

Norovirus outbreaks have only started to get attention after their impact on cruise ships in the past few years.

In many instances, food employees may be infected with hepatitis A or norovirus and not show symptoms and can be shedding viruses without even knowing they’re sick. Another significant fact is that it usually takes only a small number of virus particles to make a person sick. Where it may take hundreds or thousands of bacterial cells to make a person ill, it would take less than ten virus particles to cause disease.

What do you think the FDA and USDA are really doing well right now?
The new approach taken by both of these organizations is to ensure food safety throughout the entire food chain. We start at the farm by implementing good agricultural practices to minimize contamination of our food supply. Certain things can be done at the farm that can help to reduce the prominence of pathogens. From there, we have good manufacturing practices, which are designed to take a product that is as safe as it can be from the farm and make it safer, whether it’s by processes like irradiation or pasteurization or by having surface contaminants removed prior to going to retail. At retail, our emphasis is once again on making sure the products we have purchased are safe and kept in that condition and that we’re not doing anything in terms of handling in supermarkets and restaurants that would result in a recontamination of the food.

In those cases where a product like raw meat or poultry is likely to have bacteria, we need to make sure we are cooking the food properly and following the steps to ensure those disease-causing organisms are reduced to a safe level before eating the food.

What food safety issues aren’t being addressed by the FDA and USDA but should be?
I don’t know that there are any issues that are not being addressed. In some cases it’s just that our system is in need of upgrading because most of the pathogens that we’re dealing with are microorganisms. Historically, the food safety system has pretty much been based on the sensory evaluation of products—in other words, how does the food look, feel, or smell? Because most of the common causes of food-borne illness are microorganisms, you can’t detect a problem unless the product is spoiled or extensively damaged. A visual-based inspection program is not 100-percent foolproof in protecting against these microbial pathogens. Current improvements are in what we call “real-time detection,” where scientists are developing tests for these microbes so we can take samples from the surfaces of carcasses and other foods and provide prompt results. In this way, contaminated products can be prevented from entering the food chain.

Federal agencies are looking into how to protect the food supply from terrorists. How can terrorists attack our food supply and what is needed to protect it?
Certain viruses could be spread or botulism may be used. The real key is that we do have a global food supply and a vast majority of the products we eat in the U.S. come from outside sources and it’s difficult to maintain control. But the USDA and FDA are typically trying to maintain an effective system for monitoring those products. One of the things on the horizon is country-of-origin labeling so we can track these products.

Would this be more of a threat from imported food?
Wouldn’t have to be. One of the first cases of terrorism came from a domestic situation in which a group was trying to disrupt a local election and contaminated food on a salad bar with salmonella bacteria. But the chance to have a sizable effect on the health of people would not be nearly as great using food with a biological agent as it would be if you used smallpox with its rapid person-to-person spread. You could make a small group of people sick, which would attract media attention and might raise the level of fear. If that’s the terrorists’ objective, they can achieve that, but if a terrorist wants to have a catastrophic effect, there are probably more effective approaches than using our food supply.

Why are people worried about genetically engineered fruits and vegetables?
It’s probably as much of a lack of consumer education as anything. In the opinion of the food science community, the health risk associated with eating a genetically modified organism (GMO) is pretty small. There may be a very, very minor risk with people with certain sensitivities or allergens, although I’m not sure that it is any greater with genetically modified organisms than it would be with any other product that might contain allergens. We’ve used genetically modified organisms in the United States for decades now and have not seen any major problems. I think if there is a concern for GMOs, it may be more of an environmental impact than a health impact.

What are the food safety issues in the typical kitchen?
We have seen certain kinds of meat products like hot dogs and bologna linked to Listeria monocytogenes and in practically all cases, the risk of contracting a food-borne illness is going to be highest among the most susceptible populations: the very young, the elderly, people with some sort of an immune deficiency, and pregnant and lactating women, because they run the risk of passing the pathogen to their child. Things like poultry should be cooked well because there’s salmonella and other bacteria that are pretty much just inherent. Same with ground beef.

The other thing I’m concerned about in kitchens is cross-contamination. People will cut raw poultry on a cutting board and then, without cleaning and sanitizing the board, the knife, or their hands, they chop up the ingredients for a salad. So now you’ve got bacteria transferred from the raw chicken to a salad that won’t be cooked and you won’t get the thermal destruction of the bacteria. Preventing cross-contamination, good personal hygiene—especially hand-washing, and proper sanitation of cutting boards and counter tops—are things that consumers should think about.

How about alfalfa sprouts?
Some people at the top level of the food science community say sprouts, by their very nature, are probably the most high-risk food a person can eat. In many cases, the pathogens are actually in the seed and unless they are disinfected in some way, that’s a problem. In some cases, depending on the way they were produced, they might be healthy, but I think it’s sort of like the raw oysters. If you choose to eat them, you definitely are raising your risk.

Overall, do you think our food system is safe and being regulated properly?
It’s not to say we don’t have food-borne illness, but if you look at the number of meals served and the amount of food produced and sold in this country, people have a relatively low risk and they should not be alarmed in any way. Our food safety system works and it’s being improved all the time. But the last line of defense is really the consumer, and they should view themselves in that role because ultimately they can do things to protect or endanger themselves or their families.

David McSwane is an associate professor at the School of Public and Environmental Affairs, IUPUI. His expertise is in food safety, drinking water safety, and the health effects on environmental hazards. He is teaching courses on environmental health policy and food science and sanitation.