Argyris Magoulas is a member of the Food Safety Education Staff at the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service.

You know what it means when spring turns to summer—warmer temperatures. Do you know who likes warmer temperatures as much as us fun-loving humans? Tiny, invisible bacteria! These creatures thrive and multiply unseen in the warmth of the season, and this bad bacteria can seriously spoil the fun. However, you can reduce your risk of foodborne illness and still enjoy your summer fun.

Bacteria exist everywhere in nature. They are in the soil, air, water, and foods we eat. When bacteria have all the right factors to grow—nutrients (food), moisture, time, and favorable temperatures—they increase in numbers so rapidly that some can cause illness in humans.  

The U.S. Food and Drug Administration (FDA) estimates that 2% to 3% of all foodborne illnesses or food poisonings can lead to serious long-term illnesses. These illnesses can be particularly dangerous for people whose immune systems are weakened, such as during cancer treatment.

A handful of illness-causing bacteria thrive in different types of raw foods.

• Salmonella from raw or undercooked poultry can lead to serious medical complications, especially for individuals with weakened immune systems.

• Escherichia coli from raw or undercooked eggs or meat can cause kidney failure.

• Campylobacter from raw meat juices, either directly or when they contaminate nearby prepared food, may cause fever, headache, and muscle pain as well as diarrhea, stomach pain, and nausea.

Protect yourself and others with food safety

Like other living things, bad bacteria don’t like extremely cold or extremely hot temperatures.

Most bacteria that cause food poisoning stop growing at 40°F (4°C) or colder. Meanwhile, temperatures warmer than 140°F (60°C) kill most bacteria. The temperature gap between 40°F and 140°F (4°C and 60°C), called the danger zone, is where bacteria grow best. Avoid having food sitting out in this range. This can be more challenging as the weather gets warmer.

The following are good food safety tips for anyone, but especially for people with cancer:

1. Never leave food at room temperature for more than 2 hours, or 1 hour if the outside temperature is above 90°F (32°C).

2. Always keep cold food cold (at or below 40°F/4°C) by using a cooler or placing in a container with a cold source, like ice or frozen gel packs.

3. Keep hot food hot (at or above 140°F/60°C) on the grill or in an insulated container, heated chafing dish, warming tray, or slow cooker.

4. Refrigerate leftovers immediately after you are done eating, and use them within 4 days.

5. If you are not sure how long food has been sitting out, throw it out immediately.

If you have food storage questions, download the U.S. Department of Agriculture (USDA) FoodKeeper app, which offers food storage guidance for more than 400 food and beverage items. It can give you peace of mind knowing you stored and served your dish safely.

Need more food safety information? Call the USDA Meat & Poultry Hotline at 1-888-MPHOTLINE (1-888-674-6854) or email mphotline.fsis@usda.gov. You can also chat live with a USDA food safety specialist at AskKaren.gov, available from 10 a.m. to 6 p.m. Eastern Time, Monday through Friday, in English or Spanish.