foodsafety.wsu.edu

Frequently Asked Questions

	Do leftover foods need to be thoroughly reheated?
	How can I tell when eggs are cooked?
	How do I know when food is adequately cooked?
	What about fish and shellfish?
	What foods do I need to be careful to cook thoroughly?
	What temperature is needed to kill bacteria in meats and poultry?
	Why are some people advised to re-heat lunch meats and hot dogs before eating them?
	Why doesn’t chicken look done when it is cooked to 160°?
	Why isn’t color a good way to tell whether ground beef is cooked?

Do leftover foods need to be thoroughly reheated?

It is important that leftovers be refrigerated promptly after they are first cooked to prevent bacteria growth. Reheating to 165° gives an additional measure of safety in case there was bacteria growth during the cooling process.

How can I tell when eggs are cooked?

When the protein in the egg changes from a liquid to a solid, the egg is cooked adequately to kill pathogens. For egg-containing dishes, testing the temperature with a thermometer is recommended.

How do I know when food is adequately cooked?

Most people use visual cues to determine whether meat and eggs are adequately cooked. For ground beef, cooking until the beef patty is no longer pink has been recommended. A much more accurate way to determine when ground beef is adequately cooked (pasteurized) is check the temperature with a thermometer – a digital thermometer is recommended because it is the most accurate way to test temperature of thin meats such as ground beef patties, pork chops or chicken pieces.

What about fish and shellfish?

It is difficult to test temperature of fish and shellfish and there is little research data about the temperatures required to kill pathogens that may be in fish and shellfish. Currently, it is recommended that fish be cooked to 145° or else until the flesh is opaque and flakes easily with a fork. Shellfish are cooked until the shell opens.

What foods do I need to be careful to cook thoroughly?

Pathogens (germs that cause illness) that are transmitted from food animals to humans can cause serious illness and foods from animal sources are sometimes contaminated with these pathogens. At the current time, pasteurization/cooking is the primary control mechanism for pathogens in meats, eggs and dairy products. There are various time/temperature combinations that produce safe meat, eggs and dairy products that are of acceptable quality. Pasteurization is the term for heating a food to a temperature that will kill pathogens.

What temperature is needed to kill bacteria in meats and poultry?

When meat is cooked to 160°F,E. coli O157 and other pathogens are killed.

Why are some people advised to re-heat lunch meats and hot dogs before eating them?

Lunch meats and hot dogs are fully cooked by the manufacturer. However, occasionally these meats are re-contaminated with bacteria after cooking. The advice to re-heat processed meats is due to concern about killing a bacteria calledListeria that is risky for some people, including pregnant women, elderly and persons with weakened immune systems. Listeria bacteria can reproduce in the refrigerator so that if a few bacteria are in the package of lunch meat or hot dogs, the number ofListeria can become very high during the time these meats are stored in the refrigerator.

Why doesn’t chicken look done when it is cooked to 160°?

Chicken looks done at a higher temperature than is required to “pasteurize” it or cook it sufficiently to kill pathogens. Most people prefer chicken cooked to 170° for pieces and 180° for whole chicken.

Why isn’t color a good way to tell whether ground beef is cooked?

Sometimes ground beef will turn brown at a temperature well below that which will kill pathogens – sometimes as low as 130 to 140°. Other times, the ground beef remains pink when the meat is cooked to a temperature of 170°. The U. S. Department of Agriculture has launched a campaign to encourage consumers to cook food to a safe internal temperature (for additional information see www.fightbac.gov andwww.fsis.usda.gov/thermy.