I’ve been listening to my favorite podcast again. It’s called Risky or Not. This podcast is produced by two Extension Food Safety Specialists, our own Dr. Ben Chapman from NC State and Dr. Don Schaffner from Rutgers in New Jersey. In each episode they address one food safety topic. Usually, they answer question related to food, cooking, food preservation or storage. They look at research and the science and give their rational for deciding if it is risky or not.

The one I was interested in was on overnight oatmeal.

Have you heard about this? The concept is you prepare oatmeal the night before so you can have breakfast in a hurry. Recipes for overnight oats vary, but typically they are oats mixed with milk or water and allowed to soften overnight. Overnight oats are eaten cold.

When looking at different recipes, there are some inconsistencies in instructions and storage of this mixture. Some recipes use warm water instead of milk, while others cook the oatmeal and still others just mix the uncooked ingredients together. They also differ in where the mixture is kept overnight. The question is: should overnight oatmeal be put into the refrigerator or set at room temperature? Is there a food safety concern with any of these methods?

This led to Risky or Not episode # 766 Room Temperature Overnight Oats

Both professors identified keeping the overnight oats at room temperature as risky. Their main concern is a biological pathogen called Bacillus cereus. This pathogen is often found in grain products, but can also be found in meats, starchy foods, soups, stews and sauces. It causes vomiting, diarrhea and stomach pains. If the pathogen is present in the food, a toxin could develop when the food is heated and then subjected to temperature abuse. This means it wasn’t cooled quickly enough or sat at room temperature too long.

Another thing to note about B. cereus is that once the toxin is formed, it can’t be killed - even with heat. Refrigeration can help mitigate the development of B. cereus.

The professors agree that grain foods that have been cooked should not be left at room temperature. So, if you cook oatmeal to be reheated and eaten later—be sure to cool it quickly and store in the refrigerator. But what about uncooked oats? They both felt that the environment was right and leaving a mixture of uncooked oats combined with a liquid at room temperature overnight could result in pathogen growth. All the paths led to risky. However, they said if the oat mixture is stored in the refrigerator overnight there is not a problem.

I hope all this talk about pathogens hasn’t turned you off of trying overnight oats. Ready to give it a try? Here’s a safe recipe from our Med Instead of Meds website.

You can develop your own favorite recipe, use what you have on hand. The chia seeds are optional. You can omit the sweetener, too. Play with the ingredients until you get the texture and flavors you like. For a thicker or thinner final product, just adjust the amount of liquid accordingly. Don’t risk it, when making overnight oats, store the mixture in the refrigerator.

Leaving food out overnight seems to be a frequent question sent to the Professors for Risky or Not. Many podcast episodes address the safety of foods kept out overnight. Some of these include: soaking beans, sushi left on the counter, homemade cookie dough left out, guacamole and roasted grilled veggies. Hint: In most of these cases, the Professors said leaving these foods out overnight was a risky practice. If you’d like to know more about this topic, you can listen for yourself at riskyornot.co (yes, that’s co not com). Search for “overnight” at the Search/Tag button.

Syracuse is a Family and Consumer Science team member and can be reached at N.C. Cooperative Extension, Brunswick County Center 910-253-2610or by email at clsyracu@ncsu.edu