Do you use the same kitchen sponge for days on end? Let your takeout pizza languish on the counter overnight?
We all have questionable kitchen habits – but when it comes to food safety, shortcuts we think of as harmless can open the door to dangerous pathogens such as bacteria and toxins, according to microbiologists. Here’s how experts suggest staying safer in the kitchen.
“Home cooks tend to underestimate how cross contamination can spread bacteria across the kitchen,” says Dr Siyun Wang, professor of food safety engineering at the University of British Columbia. E coli, salmonella and listeria can easily transfer from raw produce, meat and eggs to other points we touch, such as a refrigerator or faucet handle, where Wang’sresearchhas shown they may be able to linger for weeks.
To avoid cross-contamination when cooking, wash your hands frequently and well – for 20 seconds under warm water, then dry them on a clean towel reserved especially for that purpose.
Do not rinse rawmeat, such as chicken, she says. Doing so may help spread harmful bacteria, including via tiny airborne water droplets.
Sanitize surfaces:Dr Jae-Hyuk Yu, a professor of bacteriology at the University of Wisconsin-Madison, recommends using a bleach solution (one tablespoon of bleach per gallon of water), an Environmental Protection Agency-registered kitchen disinfectant, or an alcohol-based spray for sanitizing hard surfaces, especially after preparing raw meat. And when handling cleaning chemicals, use gloves and ventilate well. He recommends cleaning fridge shelves monthly and ensuring your fridge is consistently under 40F to prevent bacteria from lurking around.
Cook meat thoroughly:Always cook meat to its proper internal temperature, per the United States Department of Agriculture’sguidelines: 145F for whole cuts of beef, pork, lamb, veal and fish (with a three-minute rest for meat), 160F for ground meats, and 165F for all poultry. Yu uses plastic cutting boards, rather than wood, for meat. “Even clean boards can harbor microbes in grooves,” he says, so wash any kind of board well with hot water and antibacterial soap after use.
“Sponges are notorious bacterial reservoirs,” says Yu. “Cleaning a knife used on raw chicken with a sponge, then using that same sponge on other dishes, can absolutely spread dangerous pathogens.” If you must use a sponge, microwave it, wet, for one to two minutes once a day or run it through the dishwasher with a heat-dry cycle, he advises. Yu replaces kitchen sponges every one to two weeks, and personally prefers sanitizable dishcloths that can be changed daily and put through a hot laundry cycle.
While it is convenient to thaw frozen meat at room temperature, doing so “allows the outer layers to enter the ‘danger zone’ between 40F and 140F, where bacteria can multiply rapidly, long before the center is thawed,” says Yu. Instead, thaw meat in the refrigerator. If you want to cook the meat immediately, use the microwave or place it in a sealed bag and submerge it in cold water, changing the water every 30 minutes. These methods keep the temperature in a safe range and limit bacterial growth.
Leaving food out at room temperature is “essentially incubating the bacteria that are in that food”, says an Idaho-based microbiologist and medical laboratory scientist certified by the American Society for Clinical Pathology who goes by thepseudonym Morticiato avoid harassment as she shares food science information online. This gives them time to produce enterotoxins that can lead to symptoms like vomiting. “A lot of these toxins are heat stable,” she says. Reheating them may get rid of bacteria, “but the toxins will still make you sick”.
Morticia recommends being especially careful with starchy leftovers like rice and pasta, whereBacillus cereus, a nasty foodborne pathogen, can start to grow within hours if left out.
If you’re saving food for later, refrigerate it within two hours. If you’re actively eating over time – say, at an indoor party – food can stay out for up to four hours. But in hot outdoor settings such as a barbecue, that window shortens, she explains.
The Food and Drug Administration and USDArecommendkeeping refrigerated leftovers no longer than three to four days. “If you freeze food, it will stay safe to eat for a very long time,” Morticia says.
“Respecting these dates is one of the best ways of avoiding potential health problems,” says Dr Alvaro San Millan, an expert in bacteria at the National Center for Biotechnology in Madrid.
Some foods, such as packaged snacks, may be fine to eat days or weeksafter their best before date has passed, particularly if they’re unopened or have been properly stored. But it’s not always easy to tell if something has gone bad.
“If food smells or tastes funny, that’s definitely a red flag,” says San Millan. But pathogens can accumulate without alerting our senses to trouble. “Certain bacteria, such as salmonella, can produce infections in humans even if they are at a very low concentration in the food – so low that you could never appreciate any change in a sniff or taste test,” says San Millan.
Most of the time, eating questionable food will probably only lead to some gastrointestinal discomfort, but “if you are unlucky and get infected by bacteria such as Listeria or Salmonella, or intoxicated with botulinum toxin, you may be in serious trouble,” he says.
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Can you just get rid of the visible mold on cheese and eat the rest? “It depends on the type of cheese,” says Wang.
If you spot mold on soft cheese, such as cottage and cream cheese, “the entire product should be discarded”. Mold can send microscopic threads throughout the cheese, contaminating more than what is visible on the surface.
“For hard cheese such as cheddar, you can cut off at least 1in around and below the mold spot and keep using it,” Wang says, because fungi aren’t able to spread as quickly through denser textures. “The knife should be kept away from the moldy part to avoid cross contamination,” she says.
People have used food preservation techniques like salting and pickling for millennia. But simply adding preservative ingredients to a dish doesn’t “shield” it from bacteria. Spicy, salty or acidic elements might slow spoilage under specific conditions, as with jerky or sauerkraut, but don’t guarantee protection from harmful pathogens. There have been listeria and salmonella outbreaks from pickles, for instance, notes Morticia.
“There isn’t much of a difference in regard to bacterial contamination and pathogen transmission” when it comes to organic and conventional produce, Morticia says.
However, when buying local, “the supply chain is a lot shorter and fewer people are coming into contact with that food,” she says. This means “you are at a lower risk of transmission of some pathogens,” she says.
Unfortunately, individual consumers don’t have total control over food safety – systemic factors have a significant impact on the quality of what we eat.
The FDA has faced significantreductionsin funding and staff, which “could lead to gaps in inspection and monitoring”, says Yu.Reportssuggestthat spending freezes are already limiting food safety inspectors’ ability to travel to farms or acquire food samples for testing.
For individuals at home, less regulatory oversight means higher stakes decisions at the grocery store. Common food categories such as meat, eggs, shellfish, sprouts, greens and seeded vegetables such as tomatoes and cucumbers are allrelatively high-riskfor contamination.
“Now is a good time for consumers to be more cautious,” says Yu, particularly with “high-risk foods like leafy greens, especially bagged lettuce,” which is prone to contamination with pathogens such as salmonella, listeria and E coli because of the way the greens are mixed from different farms and mass-processed before packaging.
Morticia has changed her eating habits to prioritize safety in light of weaker industry regulations. “I went vegan in January, because most foodborne pathogens are zoonotic in origin, meaning they come from cows and pigs and chickens,” she says. She’s also opting for more stir-fries and fewer salads. “Cooking all of my foods significantly lowers risk,” she says.