Lansing - The Michigan Department of Community Health (MDCH) and several local health departments are investigating an increase in the number of illnesses related to the bacteria E. coli O157. MDCH has received reports of 29 cases of infection so far in the month of June. In the past four years, Michigan has averaged 10 cases for the month of June.

"This is a striking increase compared to what we have seen in previous years," said Dr. Gregory Holzman, chief medical executive for MDCH. "It is extremely important that people thoroughly cook their hamburgers to ensure their health and safety."

Although the investigation is ongoing, early laboratory results, including DNA analysis of the bacteria, indicate that several of the illnesses may be linked, suggesting a common food source. Preliminary information collected from patients indicates ground beef is most likely the source.

Historically E. coli infections have resulted from the consumption of contaminated ground beef. Public health officials would like to remind consumers that using a digital instant read food thermometer is the only way to be sure a ground beef patty is thoroughly cooked at a high enough temperature to destroy any bacteria that may be present. The minimal internal temperature for a hamburger patty is 160° F and just using color as an indicator of doneness may not be adequate. The USDA data show that eating pink ground beef patties without using a thermometer is a significant risk factor for foodborne illness.

Some kinds of E. coli cause disease by making a toxin called Shiga toxin. The bacteria that make these toxins are called "Shiga toxin-producing" E. coli, or STEC for short. The most commonly identified STEC in North America is E. coli O157:H7. The symptoms of STEC infections vary for each person but often include severe stomach cramps, diarrhea (often bloody), and vomiting. If there is fever, it usually is not very high (less than 101˚F/less than 38.5˚C). Most people get better within 5-7 days. Some infections are very mild, but others are severe or even life-threatening.

Keep your cookouts and picnics safe by following basic food safety guidelines provided by the Partnership for Food Safety Education:

- Wash your hands with warm water and soap for at least 20 seconds before and after handling food.

- Always marinate foods in the refrigerator, not on the counter or outdoors. Don't use sauce that was used to marinate raw meat or poultry on cooked food. Boil used marinade before applying to cooked food.

- When grilling foods, preheat the coals on your grill for 20 or 30 minutes, or until the coals are lightly coated with ash.

- If you partially cook food in the microwave, oven or stove to reduce grilling time, do so immediately before the food goes on the hot grill.

- When it's time to cook the food, cook it to a safe internal temperature. Use a food thermometer to be sure.

o Beef, veal and lamb steaks and roasts: 145 °F for medium rare, 160 °F for medium, and 170 °F for well done.

o Ground pork and ground beef: 160 °F.

o Poultry: to at least 165 °F.

o Fin fish: 145 °F or until the flesh is opaque and separates easily with a fork.

o Shrimp, lobster and crabs: The meat should be pearly and opaque.

o Clams, oysters and mussels: Until the shells are open.

- Never place cooked food on a plate that previously held raw meat, poultry, seafood or eggs. Be sure to have on hand plenty of clean utensils and platters.

- Grilled food can be kept hot until served by moving it to the side of the grill rack, just away from the coals where it can overcook.

Never let raw meat, poultry, eggs, cooked food or cut fresh fruits or vegetables sit at room temperature more than two hours before putting them in the refrigerator or freezer (one hour when the temperature is above 90 °F). For additional information, visit www.usda.gov or www.cdc.gov and search for food safety or E. Coli.