Wednesday, August 3, 2005BY LOIS MAHARG
Ann Arbor News Bureau
‘When in doubt, throw it out” is never better advice than during picnic season, when food sits out in the hot summer sun.
“Bacteria grow well between 70 and 120 degrees, but they grow most rapidly between 90 and 110 degrees,” said Joan Miller, extension educator at Michigan State University Extension. “And in a picnic setting generally there’s a lot of moisture in the air that allows bacteria to grow fast.”
These bacteria – E. coli 0157, Salmonella, Listeria, Campylobacter – can wreak havoc on the gastrointestinal tract and, in some cases, lead to serious illness and death.

To prevent food-borne illness, the United States Food and Drug Administration recommends that perishable food be out no more than two hours, or one hour in temperatures above 90 degrees. Food that sits out longer should be tossed, Miller said.
Picnickers can reduce the chance of food poisoning still further by observing a few simple rules.
Keep cold food cold, in insulated coolers with gel packs, when carrying it in and out.
Pack coolers full, to keep the temperature down.
When possible, use separate coolers for beverages, which will be opened frequently, and perishables, which should remain closed.
Wash hands with soap and water in the outdoors, and make sure all food handlers do the same.
A report released in April by the Centers for Disease Control and Prevention shows the incidence of food poisoning in the United States declining in recent years.
But with 76 million people in the United States becoming ill from food-borne pathogens every year, according to the United States Department of Agriculture, food-borne illness is still a public health issue.
Stringent regulations for food handling in commercial settings have led to fewer instances of food poisoning at restaurants in recent years, yet “There’s more concern for how we handle our food once we get it home,” said Holly Scherer, a registered dietician with M-Fit at the University of Michigan.
So what can be done to cut down on the risk of food poisoning at home? Cross-contamination – cutting up raw chicken and then fruit on the same cutting board, for example, thereby transferring harmful bacteria in the meat juices to the fruit – is one thing to avoid, say food safety experts.
“One of the best tips for working in the kitchen is to have several cutting boards in different colors,” said Lisa McDowell, nutrition services manager at St. Joseph Mercy Hospital. Use one color chopping board for chicken and another color for fruit and vegetables. After each use, wash cutting boards and disinfect them with a diluted solution of bleach, allowing them to dry between uses.
Another potential source of cross-contamination is the ubiquitous kitchen sponge.
“Everybody loves sponges,” Miller said. “Yet they’re maybe the most infectious source of bacteria in the home.” Wet sponges supply the moisture and nutrients needed for bacteria to grow, and these bacteria can survive for up to two days while a sponge is drying.
Ideally, Miller said, sponges should be allowed to dry between uses and replaced once a week. Consider using dish towels rather than sponges, she suggested. Launder the towels frequently in hot water and allow them to dry completely between uses.
Cross-contamination can also occur when a marinade used on raw meat is then served as a sauce at the table, McDowell said. This problem can be avoided by reserving part of the marinade.
Unwashed fruit and vegetables are another source of food-borne illness that can be prevented by washing produce in cold running water and rubbing it gently with the hands or a vegetable brush, Miller said. Most pesticide residues will be removed in the process, she added.
However, the U.S.D.A. recommends not rinsing meat. Bacteria on the surface will be killed when the meat is cooked, and the rinsing process may contaminate utensils and countertops.
Food-borne illness can also result from the improper thawing and cooking of meat, Scherer said.
Defrost meat in the refrigerator rather than at room temperature, she advised. Otherwise, the outer parts, which thaw more quickly than the inside, may sit for hours at temperatures conducive to the rapid growth of bacteria.
When it comes to deciding how long to cook meat, looks don’t tell. “You can’t tell by the color,” Scherer said, adding, “the only way to tell when meat has been cooked enough is to use a meat thermometer.” (See sidebar.)
Deciding when to throw leftovers out at home can be a tricky business. Different foods have different shelf lives, and you can’t always base your decision on a food’s appearance or smell.
While leftover fish should be eaten the next day, McDowell said, roast beef and pork may be good for up to three to five days. Vegetables, on the other hand, may last a week, she said.
According to Miller, raw eggs in their shells are usually good in the refrigerator for four to five weeks beyond the packing date, or about three weeks after purchase at the store. Commercial mayonnaise, refrigerated after opening, and should be safe for up to two months. Cooked eggs, however, should be eaten within two days, McDowell said.
In general, the less time perishables sit out at room temperature, the safer they’ll be. So refrigerate leftovers quickly, keeping the refrigerator at 40 degrees or below. And at the grocery store, plan to collect the perishable items last.