I recently moved to a rural area, and it takes about 25 minutes to drive to the nearest grocery store. A friend suggested we keep a cooler in the trunk to put perishables in as we leave the store. That seems like overkill. Is it necessary?
It’s not a bad idea, especially during hot weather. Although the normal guideline for perishable foods is to make sure they remain in the “danger zone” of 40 to 140 degrees F for no longer than two hours, that time frame shortens to just one hour when it’s 90 degrees or hotter. So, when it’s hot outside, it’s important to do what you can to keep food as cool as possible.
It’s important to note that the time limit for the danger zone is cumulative: That is, if food remains in the zone for 45 minutes between the time you put it in your cart at the grocery store and the time you get it in the refrigerator or freezer at home, the time it can be in danger zone later — when you’re preparing it, for example — decreases to an hour and 15 minutes, or just 15 minutes at temperatures above 90 degrees. And that’s assuming that the food hasn’t been in the danger zone before you get your hands on it.
What’s so magical about this time limit? Well, given the right conditions, most bacteria that cause foodborne illness will double in number every 20 minutes. As ambient temperatures rise to 90 degrees F and above, bacteria multiply even more quickly. The more bacteria, the more likely it will make you ill. And even if these bacteria are in raw meat or other foods that you will cook before eating, they can still make you sick if you don’t cook them to the right temperature for long enough or if they produce toxins that aren’t destroyed by the cooking process.
Here are a few guidelines from Foodsafety.gov, the online gateway for federal food safety information, about grocery shopping and food safety:
- Be smart about the path you take in the grocery store. Go through the canned food section first, so the food that’s in your cart the longest is non-perishable. Fresh meats should be the last items to go into your shopping cart.
- In the cart, be sure to separate raw meat from fresh produce and other ready-to-eat items to prevent cross-contamination. Many stores have lightweight plastic bags, like those in the produce department, also available in the meat department to help protect other grocery items from any stray raw meat juices.
- Ask the cashier to bag raw meat separately from other items.
- Drive directly home from the grocery store. If you have other stops to make while in town, do so before you do your grocery shopping.
- If you use reusable grocery bags, be sure to wash them often. Cloth bags can be washed in a washing machine and dried either in the dryer or air-dried. Plastic-lined bags should be scrubbed using hot water and soap and air-dried. Be sure the bags are completely dry before storing or using them. If you have insulated bags, ask the cashier to use them for perishable items to help keep them as cool as possible.
Chow Line is a service of the College of Food, Agricultural, and Environmental Sciences and its outreach and research arms, Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH 43210-1043, or firstname.lastname@example.org.
Editor: This column was reviewed by Sanja Ilic, Ohio State University Extension’s food safety specialist.
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