Cheese, ice cream, hamburger, strawberries, raspberries, apple cider, and alfalfa sprouts have made people sick — or worse. What's going on?

You wash your hands. You wash your fruits and vegetables. You wash the kitchen counters before, during, and after you fix anything to eat. The only thing red on meat from your kitchen is ketchup. Is it safe to eat?

Probably. The problem in 95 percent of food-borne illness outbreaks, according to Centers for Disease Control data, is improper handling and preparation by retail establishments and consumers.

But washing fruit and vegetables at home will not necessarily remove a dangerous organism, says Merle Pierson, professor of food science and technology at Virginia Tech. Control has to begin during production and continue through every stage of the food chain.

There's a three-fold responsibility in producing safe food, he says. “One is the business responsibility. If you produce an unsafe product, you are going to have problems staying in business. Two is the regulatory/legal issue. If you are involved in producing an unsafe product, you will be subject to regulatory action and could even go to jail.

“Three is the moral responsibility. Every person in the food system has a moral responsibility to carry out their role in producing safe food products. That should be the primary motivating factor.”

In the United States, “We have better recognition than ever of problems with food-borne illnesses. We've known about the E. coli O157:H7 microorganism for more than a decade; yet, it caused recent illness from hamburger and fruit.”

Sometimes we are victims of our super-efficient system: “If foods have not been properly handled, the numbers of consumers affected by contaminated food from one source can be large,” he points out. For example, 18,000 people in the Chicago area became ill from salmonellae in milk.

Another area of concern is imports. “We are importing food from all over the world, and we do not have good control over production processes and handling conditions that might affect our safety.” The result -- strawberries from Mexico that carried hepatitis A and raspberries from Guatemala that carried pathogens traced to the water used to mix pesticides.

The response has been that all segments of the food system are starting to pay closer attention to their areas of responsibility and governments are increasing regulatory activities.

More industries — from primary production and harvesting to processing, distribution, and retailing — are using (and demanding that others use) a food safety management system based on Hazard Analysis and Critical Control Points (HACCP).

HACCP is simply a food safety management system for identifying hazards and steps in processes at which hazards must be controlled. Different approaches and interventions are often required for different products. Virginia Tech researchers help develop HACCP principles and training programs that are used by industry and government, such as food safety systems for seafood, meat, poultry, and dairy products.

Cleanliness is a first step — in field and factory, and then in our homes. By the time food reaches our kitchen, bacteria may be too attached to wash off.

Bacteria produce compounds that attach them to a surface — of food itself or where food is prepared. This can happen very quickly and washing will not remove them,” says Pierson. Imagine trying to wash sand off sandpaper.

Virginia Tech scientists are doing research to determine the mechanisms of attachment and are studying methods for removing bacteria during sanitation. “For example, we are identifying where and how they attach to stainless steel and gaskets in food processing equipment,” says Pierson.

“It's a complex process and the numbers of organisms only increase over time, so the more quickly and thoroughly systems can be cleaned, the better,” Pierson says. “But the big problem in sanitation is that once attached to surfaces, bacteria are becoming more resistant to cleansers.”

Cooking and cooling are also often critical control points — including in your kitchen. What you do with leftovers -- and procedures manufacturers follow in precooked foods — determine whether they are safe to eat. Virginia Tech's researchers have determined that many raw foods spoil before they become dangerous. “Raw hamburger kept at 55 degrees Fahrenheit spoils in a day,” Pierson says.

But precooked foods can become unsafe before you can tell they are spoiled. “For example, if you put a big pot of beef stew in the fridge, it takes several hours to cool. Heat resistant microorganisms could grow and their presence would not be evident when you take the stew out to eat it. So precooked foods, if they are not properly refrigerated, can present a hazard.”

Virginia Tech is doing research to understand and predict the circumstances in which pathogens grow. Pierson says, “There are tens of thousands of different kinds of foods and preparation procedures. We are developing predictive models that will allow us to plug in such factors as time, temperature, and acidity to predict how these conditions would influence the growth of pathogens.”

In the meantime, you didn't like leftovers anyway.

— Written by Susan Trulove