Sell-by dates | Things to Know

Unpacking the groceries doesn’t ensure that food gets eaten — if it sits on the pantry shelf or the refrigerator long enough it may get chucked in the garbage — especially if the package sell-by date comes and goes. This contributes to an enormous amount of food waste each year, even though some items are still perfectly safe to eat. For perishable items that might actually make you sick, researchers have developed higher-tech ways of tracking a food’s shelf-life. 

Find out more: The dating game: When food goes bad 

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Transcript

Knowable Magazine : “Consider this package of pasta. It’s unopened and looks perfectly edible. But according to the expiration date, it was best by about nine months ago. So, can you still eat it?”

“When it comes to expired products, we tend to err on the side of caution. As a result, lots of food gets tossed out, contributing to the estimated 40 percent of food that goes to waste in the US. But what does an expiration date actually say about a food’s safety? Not much, according to food scientist Maria Corradini.”

Maria Corradini (food scientist, University of Guelph): “In general, none of these labels is directly related to food safety.”

Knowable Magazine : “Although the packages exact wording can vary, Corradini says these dates fall into two general categories: ‘use by’ and ‘best by.’ The use-by date is for perishable goods that usually need to be kept cold. She says this type of label is the closest to a true expiration date because these items are more susceptible to pathogens that can spoil food and make us sick. The best-by label and its analogues apply to non-perishable goods. This date indicates when a product is past its peak quality, so it may have less flavor or nutritional value, but consuming these products after their best-by date is pretty low-risk [unless item is visibly damaged or spoiled].”

Maria Corradini: “These products are not going to be as good. However, in most cases, they are not going to harm you. There is no need to waste them.”

Knowable Magazine : “All of these expiration dates are just estimates. They can’t account for uncontrolled environmental conditions that foods face, like temperature or humidity. That’s why researchers like Corradini are developing technologies that provide real-time information on when a product has gone bad. These devices are often incorporated into food packaging. It can change color to indicate unsafe temperatures or fluoresce in the presence of harmful pathogens such as E. coli.”

“Corradini’s lab is working on a method to monitor the quality of plant-based foods like vegetable juice. Using techniques that probe the concentration of molecules in the product, she can measure molecules like chlorophyll that break down over time.”

“Ultimately, deciding whether to eat something once it’s past its expiration date depends on the type of food, how it’s been stored and the person. So what would Corradini say about eating that pasta that’s nine months past its prime?”

Maria Corradini: “Yeah — so go for the pasta.”