DEAR DR. BLONZ: Being a nut lover, I have a question after your recent column on the topic. Your information stated that nuts in their shells would keep for about six to 12 months if stored in a cool, dry place, but that shelled nuts only keep about half as long. I recently discovered an unopened 26-ounce container of lightly salted peanuts in the back of my kitchen pantry. The best-by date on the bottom was 2/26/2017, which means it is three years out of date. I assumed they would taste stale or whatever, but figured I’d give them a try. I recently opened it and found the taste and texture seemed like a brand-new container, fresh off the store shelf. The thing I do not know is whether the passage of time has affected the nutrients. Any thoughts? -- A.F., via email
DEAR A.F.: There are different methods of quality-control dating for foods. Different types of dating provide information on a range of issues, including a food’s loss of quality, the risk of microbial spoilage, and an increased risk of foodborne illness. (Check the information in an earlier column: blonz.org/we3wt.)
Nuts tend to use the “best if used by” type of freshness date, providing a date after which the contents would be expected to decrease in flavor and quality. The wild-card aspect is that one can’t accurately predict the lifespan for every product. The dates typically have a bit of a buffer, but three years seems like pushing it. My general advice is to toss out-of-date foods under the canon of “Why take a chance?”
You have sampled from that container and have found nothing wrong. Given that the peanuts show all signs of being unspoiled and edible, I would predict they would also still be nutritious. Oxidation is the main type of spoilage affecting nuts, occurring when nuts are in contact with the oxygen in the air. Vacuum-sealing keeps air away, so it limits this process. The nuts, however, continue to age as they are stored. They might taste and smell fine when first opened, even if their freshness date is history, but that quality will drop more rapidly in a long-stored package than in a container opened within its freshness period.
Fats are the most prevalent nutrient in nuts, and these suffer during oxidation. It is the short-chain fats that take the hit first. While there are not many of these in peanuts, when the nuts do turn, it makes them no longer pleasant to eat or smell. There will be an effect on some nutrients, especially those that act as antioxidants; it’s their job to react with oxygen, thereby protecting oxidizable substances such as fats.
Again, I do not advise eating out-of-date foods, but if you are going to continue eating from this particular container, consider storing it a well-sealed container in the refrigerator or freezer, as cold temperatures also help slow oxidation and other types of spoilage.
Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.