Gen Z and millennials throw food away before its best-before date - here’s how to tell if food is off

People are increasingly reliant on best-before dates and may misunderstand their purpose. Photo / 123rf

Gen Z and millennials throw food away before it’s gone off and ahead of the date on the packaging, a Harvard study has found.

The data shows this includes any label such as “best before”, “use by” or “display until”.

“Best before” dates are for quality purposes and not food safety, but people are increasingly reliant on them and in some cases misunderstand their purpose, according to Harvard researchers.

They say they are concerned about younger generations’ ignorance around food safety, and warn that modern life has made people forget how to cook and use leftovers.

The study of more than 2000 people by Harvard Law School found that Gen Z and millennials are the most reliant on food date labels when deciding to throw food out, with older people better at using their judgment and employing tried and tested methods such as the sniff test for milk.

How likely people are to throw food away prematurely depends on the type of food. Photo / 123rf

Among people of all ages, 43% reported always or usually throwing away food before its use-by date, up six percentage points since 2016.

Experts say younger people have lost the ability to trust their senses when it comes to checking if food is safe to eat, leading them to rely on dates on packaging instead of smelling, tasting or looking at the produce.

Professor Emily Broad Lieb, the founding director of the Harvard Law School food law and policy clinic, says one reason that younger adults don’t realise that best-before dates are simply a guide is because they don’t grow their own food.

“We found the youngest consumers were most likely to rely on date labels. They were most likely to think all the labels are safety dates and to throw food away at the date,” she said at the American Association for the Advancement of Science (AAAS) annual conference in Boston, Massachusetts.

In 2025, Gen Z are aged between 13 and 28, having been born between 1997 and 2012. Millennials, born between 1981 and 1996, are aged 29-44.

Date labels were first used on packaging in the UK in 1970, when Marks and Spencer put use-by dates on some items in its shops.

“There are people who didn’t have [date labels] when they started buying food,” Broad Lieb said.

“I think the further we get away from people having a role in growing, harvesting or producing food, the more people look at it like any manufactured good.

“They have less understanding of what they should be looking at.”

10m tonnes of food wasted yearly in UK

Almost 10 million tonnes of food is wasted every year in the UK and much of it gets discarded while still edible, according to some estimates.

How likely people are to throw food away prematurely depends on the type of food, data show.

People are most cautious with raw chicken and milk, but less worried about eating lettuce or cereal that is past its best-before date.

Prof Broad Lieb said: “People were the most cautious with raw chicken, which is actually something that we’re going to cook, so there should be less risk.”

Experts urge young people to use their senses of sight, smell and taste to decide when food is good or bad. Photo / 123rf

Experts are urging young people to learn to use their own senses of sight, smell and taste to decide when food is good or bad.

Dr Lara Ramdin, an industry expert in food waste and a scientist at the Upcycled Food Association, said: “As humans we rely on that statement of use by, consume by or best before, and we have forgotten to use our senses.

“I don’t want to encourage people to eat unsafe food, but I do want to encourage them to look at food, smell food and taste food.

“If you’ve got a canned good and it’s two, three or four years old, it’s going to be safe, it’s just probably not going to taste as good.”

Young people have also lost the ability to use leftovers and to purchase food frugally, she says, with bubble and squeak one example of a now neglected recipe designed to make meals out of excess food.

“We don’t plan meals, we over-buy, we’ve forgotten how to cook, and we don’t know how to use leftovers,” Ramdin said.

“That’s where the food waste is generated because people look in the fridge and think ‘What do I do with this now?’”

The UK’s Food Standards Agency says foods that have the highest risk of poisoning include raw meat, poultry, fish and dairy.

British shops only use a use-by date, which is a sign of safety, or best before, which indicates a decline in quality.

The FSA says: “Never eat food after the use-by date, even if it looks and smells OK, as it could make you very ill.

“You can eat food until midnight on the use-by date shown on a product, but not after, unless the food has been cooked or frozen.

“After the best before date listed on a product, the food will be safe to eat but may not be at its best.”