How a microbiologist cooks to avoid food poisoning

• Food poisoning affects over 48 million Americans a year and causes 3,000 deaths.
• A microbiologist shared how she prevents food poisoning when cooking with The Conversation.

Food poisoning is a common and sometimes lethal condition. Every year 48 million Americans get sick, 128,000 are hospitalized, and 3,000 die from foodborne diseases, the Centers for Disease Control and Prevention estimates.

In June, a man from Missouri infected with "flesh-eating" vibrio vulnificus bacteria after eating contaminated raw oysters died, and in September one woman died and over a dozen others were hospitalized in Bordeaux, France, after they got botulism from improperly preserved sardines at a wine bar.

While cases like these are rare, and most people who get food poisoning recover within a few days, being aware of food safety is important.

Primrose Freestone, a senior lecturer in clinical microbiology at the University of Leicester, UK, who said washing her hands before and after handling food is "instinctual," wrote about how she prevents food poisoning while cooking for The Conversation.

Check use-by dates

Freestone advises regularly checking the use-by dates of perishable items, such as vegetables, meat, or yogurt. But if something doesn't look or smell quite right before the expiry date, it could be contaminated, she said.

"If it is before the expiry date and the food package looks swollen, or when opened the food looks or smells different than expected, I throw it in the bin," she said.

Use different chopping boards for raw and cooked foods

As a microbiologist, Freestone said she would never use the same chopping board for preparing raw and cooked food. If not cleaned properly, boards can harbor harmful bacteria, according to the Food Standards Agency.

Use separate cooking equipment for raw meat or poultry and any other foods to prevent the spread of harmful bacteria and allergens. This is because if juices from raw meat accidentally touch cooked foods, cross-contamination occurs, and bacteria can spread, according to the agency.

Only eat cooked meat and shellfish

Well-cooked food is unlikely to be contaminated with harmful bacteria because heat effectively kills germs, she said. It is for this reason that she only eats shellfish that has been cooked, and measures the temperature of meat (it should be 158 degrees Fahrenheit, she said) with a thermometer before eating it.

Eating raw or undercooked shellfish can put you at risk for infections and in some cases there are no visible signs of contamination. For example, an oyster that contains harmful bacteria doesn't look, smell, or taste different from any other oyster, she said.

Don't reheat rice

High up on the don't list is reheating rice, she said. This is because uncooked rice can contain a pathogenic bacteria called Bacillus cereus.

When rice is cooked, the bacteria is killed off, but spores — which are minute, typically one-celled, reproductive units capable of producing new cells — can survive, she said.

If the rice is left to cool and sit at room temperature, the spores quickly grow into bacteria, she said, and they can produce toxins that, once consumed, can cause vomiting and diarrhea lasting up to 24 hours.