Summer officially arrived Monday. The warmer temperatures of summer often mean an increase in foodborne illness also known as "food poisoning."

One reason is because most bacteria grow fastest at temperatures from 90 to 110 degrees F. Given the right circumstances, harmful bacteria can quickly multiply in food to large numbers. When this happens, someone eating the food can get sick.

Secondly, outside activities increase in the summer, which means more people are eating outside at picnics, barbecues, on camping trips and in the harvest fields. The safety controls that a kitchen provides thermostat-controlled cooking, refrigeration and washing facilities are often not as easily available.

Mayonnaise is often thought to be a common cause of foodborne illness. However, mayonnaise is usually not the culprit bacteria is! Mayonnaise is made with acid (vinegar or lemon juice), so it actually tends to inhibit bacterial growth. Instead, the other perishable ingredients (meat, poultry, fish, eggs, cheese, cooked starchy foods, etc.) that are mixed with mayonnaise may more likely be the problem. When kept out of the refrigerator too long, they provide an environment for bacteria to grow.

Remember, in hot weather (above 90 degrees F), food should never sit out for more than one hour. Perishable food must be refrigerated within one hour in hot weather and within two hours if temperatures are below 90 degrees F. Discard any food left that is left out longer than this!

Always use coolers when taking perishable foods on the road! Here are some helpful tips for packing your cooler:

* Pack your cooler just before you hit the road. If you pack meat and poultry while it is still frozen, it will stay colder longer.

* Pack foods in your cooler in reverse-use order: pack foods first that you are likely to use last. By doing this, you avoid having to unpack and repack the cooler along the way.

* Pack plenty of ice and/or freezer packs to ensure a constant cold temperature. A full cooler stays cold longer than one that is partially filled.

* When traveling, transport the cooler in the air-conditioned passenger compartment of your car, rather than in a hot trunk.

* Keep the cooler out of direct sunlight. When outdoors, keep your cooler in the shade covered with a blanket or tarp.

* Keep drinks in a separate cooler from foods. The beverage cooler can be opened frequently while the food cooler stays closed.

* Take perishable foods in the smallest quantity needed pack only the amount of food you think you'll use. Consider taking along nonperishable foods and snacks that don't need to be refrigerated.

For more helpful food safety information, see my Living Well blog at, the Kansas State Research and Extension food safety home page at or the Partnership for Food Safety Education at