Is It Safe To Keep Using Old Plastic Food Containers? Here's How To Tell.

When it comes to low-cost kitchen items that can stand the test of time, plastic food storage containers count among my personal favorites. I’m a huge fan of big-batch cooking, so I rely on these little vessels to keep my leftover soups and braises fresh in the fridge and freezer.

But recently, after pulling a particularly well-worn container out of my kitchen cabinet, I found myself wondering just how long it had been hanging out in there and whether it might be showing its age in some undesirable ways. If you’re also wondering how vintage is too vintage for food storage containers, read on to get some answers from food scientists.

The longevity and safety of food storage containers depend on the type of plastic.

When trying to evaluate a plastic food storage container for durability and safety, you should first turn the container over and check out the recycling code.

Inside a triangular symbol, you’ll find a number from 1 to 7. According to Michael Tunick, a research chemist in Drexel University’s Food and Hospitality Management Department, the numbers you want to see are 2, 4 or 5. A 2 represents “HDPE, or high-density polyethylene, found in [items like] cooking oil bottles and milk jugs. It’s hard to break down and considered [food] safe,” Tunick said. He noted that a 4 stands for “LDPE, or low-density polyethylene, found in [items like] squeeze bottles and bread bags, considered safe and reusable.” A 5 is for “PP, or polypropylene, found in potato chip bags and yogurt containers, and safe to reuse,” he said. In addition to being food-safe, containers with the numbers 2, 4 or 5 are durable enough to be washed and reused multiple times.

The food-safe part is particularly important because, as food science consultant Bryan Quoc Le explained, “plastic components can leach from [less food-safe] plastic and migrate into the food, and many are endocrine disruptors that can impact hormone balance. Microplastics can also flake off of the plastic as the surfaces break down from repeated use.” Microplastics have been linked to effects on everything from lung and liver health to metabolism, according to Harvard Medical School.

Brand-name containers may be sturdier and higher-quality overall.

There’s often a price difference between brand-name food storage containers, like those from Rubbermaid and Tupperware, and containers made by generic brands (like supermarket house brands and big-box store brands). But is it worth ponying up some extra cash for a set of containers from a more established maker?

Trevor Craig, a scientist and food safety expert at Microbac Laboratories, said that “the name-brand companies specialise in making containers to best serve their use and business model, so they can be thicker, sturdier and better designed.” These companies built their reputations on reliable containers, and your extra dollars are paying in part for this assurance.

Budget-conscious shoppers in the year 2025 should know that “while historically there may have been some quality and material differences between brand-name food storage containers and generic ones, that gap is becoming increasingly smaller because Tupperware and Rubbermaid have been sold off to capital management groups or merged with larger conglomerates,” Le explained. So go ahead and pick up some off-brand containers (as long as you double-check the numeric codes on the bottom).

As for how long you can keep a plastic food storage container, Craig said that “there is no strict time frame,” but you should base your evaluations on its condition. “As a container ages and goes through the perils of being a container, it will start to crack, chip, warp and, to a lesser concern, smell and discolour,” he said. “Once it reaches a point where that is the case, that’s when the container should be recycled and replaced.”

Don’t use plastic containers that are more than 10 years old.

Generally speaking, your containers will tell you when they’re ready for their trash can funeral as they develop staining, scratches or odours that won’t go away no matter how thoroughly you wash. But if you come across a set of plastic containers in your auntie’s pantry or your mom’s attic, and they appear to be in mint condition but were clearly purchased over 10 years ago, it’s safest to avoid them. That’s because, in decades past, many container-makers worked with plastics that included bisphenol A, or BPA, a chemical that can leach into food and potentially influence the development of conditionslike high blood pressure, Type 2 diabetes and cardiovascular disease. 

Tupperware previously announced that as of March 2010, it had stopped using materials containing BPA in its products in the U.S., helping “BPA-free” become a major trend and, eventually, the norm for plastic storage containers. But because vintage containers may still contain BPA, it’s best to steer clear of anything made before the 2010s.

To extend the life of your plastic storage containers, avoid the dishwasher.

Anyone who’s lucky enough to have a dishwasher knows that it’s the ultimate convenience after a long session of cooking and dining. Although I’ve certainly been guilty of dropping my reusable plastic containers in the dishwasher, Le warned against this cleaning method. “High-quality food-grade plastic containers have an estimated number of dishwasher or hot water washes of 100 times,” he said. “Hot water conditions can have a strong deteriorating effect on the plastic.”

Because dishwashers involve a longer period of exposure to hot water compared with hand-washing, they’re detrimental to containers’ longevity. If you must put your plastic storage ware in the dishwasher, be sure to use the preferred rack: The top rack doesn’t get as hot as the bottom one, so heat-related damage could be minimised by placing items there.

But Craig suggested that you “hand-clean the [containers] with hot, soapy water. That will be your best method to prevent them from being damaged. I also suggest cleaning them quickly to avoid stuck-on food, as that’s going to involve more scrubbing and is likely to scratch and damage them quickly. I [also] try to avoid using harsh scrubbing tools on all my ... containers because they often can leave scratches.”