OMAHA, Neb. — Zapping frozen meals in the microwave may be fast and easy, but it also can make you sick if it's not done properly.
That message has been slow to catch on, despite a spate of illnesses last year from improperly micro-waved frozen foods. On Sunday, the government issued a new warning urging consumers to thoroughly cook frozen chicken dinners after 32 people in 12 states were sickened with salmonella poisoning.
"Given how people use microwaves, it's great for reheating, but maybe not so good for cooking," said Doug Powell, scientific director of the International Food Safety Network based at Kansas State University.
The problem is that microwaves heat unevenly, and can leave cold spots in the food that harbor dangerous bacteria, such as E. coli, salmonella or listeria. So microwaving anything that includes raw meat, whether it's frozen or thawed, can cause problems.
"I think most food-safety experts probably would have said it's not a good idea to microwave anything that's from a raw state," said Michael Davidson, a University of Tennessee food microbiologist.
Many people wrongly assume all frozen meals are precooked and only need to be warmed. It's a misconception fostered in part by foods prepared to appear cooked, such as chicken that has been breaded or browned.
In reality, even some meals designed to be microwaved can be unsafe if they are not heated thoroughly enough, or are cooked using directions meant for a microwave with different wattage.
The government doesn't track microwave-related food-borne illnesses, but every year more than 325,000 people are hospitalized for food-related illnesses. Last fall, hundreds became ill when Banquet pot pies made by ConAgra Foods were linked to a salmonella outbreak and frozen pizzas made by General Mills were tied to an E. coli outbreak. Both products were recalled.
Since then, food companies have revamped the cooking instructions on their frozen foods to ensure they are sufficient for killing off any dangerous bacteria, says Leslie Sarasin, head of the American Frozen Food Institute trade group.