Ask the Expert: Does Peanut Butter Need to Be Refrigerated?

Once you open that jar of peanut butter, it's recommended to refrigerate the peanut butter because the colder temperature helps prevent fungus growth, which naturally produces aflatoxin, a fungal toxin that has linked to cancer in animals.

Chef and nutritional health counselor, Diane Hoch, at The Food Evolution suggests refrigerating peanut butter to minimize the fungal toxins that can grow inside the jar.

There has been much talk and concern about aflatoxin being present in peanut butter and its connection to liver cancer. The truth is that there is a certain amount of aflatoxin present in all peanuts.

As peanuts grow in the soil, aflatoxin is produced from a fungus created with moist soil and the soft shell of the peanut. Because of this, aflatoxin presents itself in both organic and non-organic peanuts — organic being the lesser of the two.

Refrigeration helps to prevent fungus growth since bacterias stop growing in colder temperatures. For this reason, I recommend refrigerating all peanut butter. When any type of nut is made into a butter, it is furthering the process of breaking down the food, and for this reason alone I like to refrigerate any butter made from nuts.