Not All Foodborne Bacteria Are Bad, Some May Be Beneficial to Your Health: Here’s What You Need to Know

Bacteria hiding in foods can make those foods delicious and even deadly. Why are some bacteria in food safe and even beneficial, while others are harmful and can cause illness?

“Over millions of years, bacteria have evolved into different types, with some developing a beneficial relationship with us, and others evolving into more toxic forms,” says Maria Tucker, a registered dietitian and nutrition educator at Duke University. “This evolution has actually resulted in some bacteria being good for us and some bacteria being bad for us.”

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Beneficial bacteria

Fermented foods—yogurt, kefir, tempeh, miso, sourdough bread, and some cheeses, to name a few—owe their unique and delicious flavors to the bacteria that live there.

Bacteria break down certain components of food. This creates new flavors and textures. Sometimes microbes are captured from the air (like in homemade sauerkraut, for example), and sometimes a specific group of microbes is added (like in yogurt).

Lactobacilli And Bifidobacterium are well-known examples of good bacteria found in food, but there are many others. According to a study published in the journal Food, Some of these microbes, called probiotics, have been shown to improve health by, among other things, increasing nutrient bioavailability and generating compounds that help reduce inflammation, regulate the immune system, and support gut and metabolic health.

However, in a recent Advances in nutrition study on fermented foods, the authors note that some people should use caution with fermented foods and probiotics. Pregnant people, people with weakened immune systems, and people with irritable bowel syndrome or small intestinal bacterial overgrowth should be especially careful. The authors also warn that in many cases, marketing claims have not been scientifically validated.

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Harmful bacteria

However, as Tucker points out, some microbes cause a lot of problems. According to the World Health Organization, each year, more than 600 million people around the world become ill after eating contaminated food. Of these, some 420,000 die. Young children and the elderly are most at risk.

Some of the most well-known foodborne bacterial killers are E.coli, Listeria, Salmonella, ShigellaAnd Staphylococcus aureus, Tucker said. These bacteria are not added to foods or encouraged to grow there, unlike good bacteria. Instead, they slip somewhere between farm and plate.

E.coli, Shigella, And Salmonella come from fecal contamination of food. Sometimes bacteria from an animal’s intestines or skin gets into meat products, Tucker says.

“That’s why we sometimes see recalls of ground beef, because there was E.coli inside.

Animal products are not the only type of food that can be contaminated. Vegetarians should also be careful. Many dangerous bacteria live in the soil or cling to people’s hands and get into food during harvesting or packaging.

How to prevent the spread of harmful bacteria

Fortunately, protecting yourself and your family is easy. Tucker says to keep four crucial steps in mind: clean, separate, cook and refrigerate.

• Do the housework: Wash your hands, utensils and kitchen surfaces often. Wash produce, too, says Tucker. Even pre-washed lettuce might need a good rinse.
• Separated: Keep raw meat, poultry, seafood and eggs separate from other foods. Always use separate cutting boards for meat and vegetables.
• Cook: Make sure food is cooked to the appropriate temperature. Tucker suggests using a kitchen thermometer. Some mark the safe cooking temperature for various foods, she says.
• Coldness: Quickly put leftovers in the refrigerator. That means, Tucker said, in an hour or two at most. Better yet, she says, freeze them. Leftovers stay safe in the refrigerator for only two to three days.

Fermented foods generally last longer, but even with foods that contain good bacteria, you have to be wary of invasions of bad bacteria. And for foods that smell bad even when they’re good (I’m looking at you, kimchi), it can be hard to tell when they’re gone.

Tucker says to watch for changes in texture or color — pink or gray in normally orange kimchi, for example, or a slimy texture.

Your food can harbor both good and bad bacteria. If you want to stay healthy, accept the good and avoid the bad.

This article does not offer medical advice and should be used for informational purposes only.

Learn more: What are the different types of food poisoning and how can you avoid them?

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