Certainly food goes bad if stored too long or incorrectly. But are food expiration dates accurate? From my experience the common advice about storing chicken seems to be set so low (outside of freezing) as to be about profits more so than food safety.
Food Expiration Dates Don't Have Much Science Behind Them
Avoiding unseen food hazards is the reason people often check the dates on food packaging. And printed with the month and year is often one of a dizzying array of phrases: “best by,” “use by,” “best if used before,” “best if used by,” “guaranteed fresh until,” “freeze by” and even a “born on” label applied to some beer.
People think of them as expiration dates, or the date at which a food should go in the trash. But the dates have little to do with when food expires, or becomes less safe to eat. I am a microbiologist and public health researcher, and I have used molecular epidemiology to study the spread of bacteria in food. A more science-based product dating system could make it easier for people to differentiate foods they can safely eat from those that could be hazardous.
Costly confusion
The United States Department of Agriculture reports that in 2020 the average American household spent 12% of its income on food. But a lot of food is simply thrown away, despite being perfectly safe to eat. The USDA Economic Research Center reports that nearly 31% of all available food is never consumed. Historically high food prices make the problem of waste seem all the more alarming.
The current food labeling system may be to blame for much of the waste. The FDA reports consumer confusion around product dating labels is likely responsible for around 20% of the food wasted in the home, costing an estimated US$161 billion per year.
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Infant formula is the only food product with a “use by” date that is both government regulated and scientifically determined. It is routinely lab tested for contamination. But infant formula also undergoes nutrition tests to determine how long it take the nutrients - particularly protein – to break down. To prevent malnutrition in babies, the “use by” date on baby formula indicates when it’s no longer nutritious.