In July, a new labeling law took effect in California to make clear the dates when foods have merely passed their prime and when they would actually be risky to eat. The rule standardizes label language (such as “Best if used by” versus “Use by”) with an aim to increase safety and clarity for consumers and reduce food waste.

The Gazette spoke with Emily Broad Leib, clinical professor of law and director of Harvard Law School’s Food Law and Policy Clinic, about the potential impact of the law, the movement to pass similar legislation at state and federal levels, and its potential to address a national problem of consumers throwing out about a third of the food they buy. The interview has been edited for clarity and length.

Gazette: California recently passed legislation regulating date labels because of their role in food waste. What was the source of the confusion?

Emily Broad Leib: We know that in the U.S. and in other places they’ve been tied to both household-level food waste and waste throughout the supply chain. I’ve heard from partners in the supply chain that sometimes food will be thrown away three months before the date because they know that’s not enough time to get it to the distributor, onto the shelf, and into someone’s home.

Another thing we see is uncertainty around whether food can safely be donated past the date. For some of these foods, the date is really just an estimate and means there’s likely nothing wrong with it. A lot of food pantries and food banks have their own guidelines, but there are fringe foods where they’re not sure: Would the company think this is still safe? This should clarify that for them.

On the consumer side, we did a national survey in 2025 and asked 2,000 Americans, “What do you think these date labels mean?”

Forty-three percent say they always or usually throw food away because of the date, not because they looked at the food, smelled it, or tasted it. That is higher than we saw in a similar survey nine years ago. Eighty-eight percent say they at least occasionally throw food away purely because of the date, and most of them say they do it for certain foods.

But the foods those people are choosing are not necessarily foods where there’s a safety-based reason to do it.

Before these labels came around, how did people tell if food was spoiling? Was food poisoning a bigger problem?

It’s really important, especially in this moment when people are hearing about food poisoning — cyclospora, or salmonella, or E. coli — to say that date labels aren’t tied to that, with one small exception, which I’ll explain. But the FDA has said repeatedly they don’t regulate date labels because they’re not tied to food safety.

In the 1950s, we started having refrigerators and freezers and full-service grocery stores. People became removed from where their food came from.

The generation before, people either grew their own food or were very close to it. If food looked good, they would eat it. If it was starting to spoil, but they could cut off the moldy part, they would do that.

By the 1970s, people were far removed from their food production and asking, “How do I know if this food is still fresh?” So companies responded with these freshness labels and, over time, states began requiring them.

Consumers understood then that it was purely about freshness, but today the majority of people think it’s about safety, and if they eat something after that date, they’re going to end up in the hospital with salmonella. That is just not true.

Then what do these labels do?

The primary use of date labels is around stock rotation, supply-chain management, and to indicate to consumers when the company believes it’s going to taste its best. There’s good reason for food companies, which are fighting for our attention and dollars, to want you to eat their product when it’s at its absolute peak.

That hasn’t been communicated well because the majority of consumers interpret them as safety dates.

Ideally, a majority of foods would have one standard label they use to indicatefreshness and peak quality.

There are a small handful of foods, however, that do become riskier after the “Use by” date. These are foods that have become contaminated with listeria, that you store in the refrigerator, and that you’re not going to cook.

The prime example is deli meat. That doesn’t mean all deli meat is unsafe — dried, cured meats like salami have low risk. But sliced turkey, chicken, roast beef, and others should be eaten within the time period on the label. If you go longer and it happens to be contaminated, it could increase your risk.

That’s the same for some prepared salads, like chicken salad or egg salad. These foods are fine to eat, but if contaminated, they can get worse over time, even if it’s in your refrigerator — because unlike other pathogens, listeria can reproduce under refrigeration.

California has said that companies need to use different label language for foods labeled for safety versus those labeled for freshness. The primary concern is people throwing food away that is actually safe to eat.

Standardizing the labels lets people know that if it smells and tastes fine, even if it is past-date, those foods with the quality label are not going to get you sick.

And California is requiring two labels, “Best if used by” and “Use by”?

It would be one or the other.

For the food with the “Best if used by” peak-quality label, it’s actually impossible to tell when it’s going to become unsafe. And if it were unsafe, it would be moldy or spoiled or no longer palatable.

Humans are pretty good at determining when something’s no longer palatable. It would smell or look gross. This standard quality label issaying, “If it still smells and tastes good, don’t throw it away. Don’t waste your money.”

The “Use by” date would be only on a small number of foods where the company is communicating, “This food is riskier. Clear this out of your refrigerator and don’t keep it past this date.”

How big a factor is consumer handling? If you leave a steak out overnight versus sticking it right in the fridge and grilling it in a day or two?

That’s a piece of it, but there are other complications, too. One is that some people don’t keep their refrigerator at 40 degrees, which is advised. If your refrigerator’s at 45, food is going to spoil faster. So there are other factors that happen at home that make it difficult to say how long food will stay at peak freshness and quality.

If you freeze meats and fish and other things, can you ignore the “Use by” date?

Definitely. In California, their required language is “Best if used by” or “Best if used or frozen by,” and same thing on the “Use by” label: “Use by or freeze by.” Again, for both types of food, the freezing stops the process that leads to spoilage or illness. Listeria cannot grow when your food is in the freezer.

We want to educate people because it’s not just food that’s wasted, people are throwing away money. About a year ago, the EPA put out a report that says a household of four is throwing away $3,000 worth of food each year. No one wants to be doing that.

How big a piece of the food waste pie is this food labeling problem?

It’s hard to say, and in my dream world we would have much better data. We do know that we waste about a third — 30 to 33 percent — of the food supply in the U.S. every year, and 35 percent of that waste happens in households. A big reason for that is incorrect understanding of date labels.

Research in the U.K. found that 20 percent of household food waste was due to date-label confusion, and I imagine it is worse in the U.S.

How many states have laws like California’s?

California’s the first one, and New York has passed a law to do the same kind of thing. The latest I checked, the New York bill is still waiting for the governor’s signature, but it’s passed both houses of the legislature. Massachusetts and other states have introduced bills to do the same thing.

When we started working on this issue, we found that 41 states required different date labels and required them on different foods. Clearly, they can’t be science-based if every state is doing it differently. But these newer laws, like California’s, are really focused on following the science and standardizing these labels.

We are now working on whether we can fix this at the federal level since there’s no science-based reason Massachusetts and Mississippi shouldn’t have the same rules.

At the end of the Biden administration, there was a Federal Register request for information by the FDA and USDA on this topic. They have not taken action, but my understanding is they’re reviewing the comments and information they’ve gotten.

There’s also a bill, the Food Date Labeling Act, that has gotten bipartisan co-sponsors in the last two Congresses. I’m delighted that states are taking action, but in the long term it makes more sense to handle this federally because it will help everyone and standardize what consumers see.