Plastic storage containers can last at least a year with proper maintenance. For many of us, plastic containers with plastic lids make up the bulk of our food storage supplies. These vessels are easy to find at retailers, they're affordable, and they're stackable (which means that they occupy relatively-little cabinet real estate). That said, plastic doesn't have the longevity offered by glass and stainless steel, so it's important to know when to swap out your container collection.
"Plastic food storage containers should be replaced every six months to one year, depending on usage and wear and tear. Over time, plastic containers can become scratched, stained, or damaged, and that starts to pose a food safety risk, explains Dragomir Markovic, food scientist and founder of Wise Intake. The safety concerns of worn-out plastic involve the scratches and punctures that can show up on these surfaces over time. "These damages can become micro-environments that can not be cleaned and sanitized properly, which can harbor bacteria and other harmful microorganisms that can contaminate food," says Markovic.
Damage to plastic containers can happen in a number of ways, but Javier and Rebeca Medina list "machine washing, using them in microwaves, scratches, and scrapes from forks and knives, and frequently using them to store oily or acidic food" as some of the most common. We found that last one especially interesting, so we asked the Medinas for more details, which they were happy to provide: "Acidic and oily food can cause plastic to degrade. Highly acidic foods donate hydrogen ions that react with and break down these long chain polymers called plastic. Fats from oil interact with plastic at the molecular level, which can cause the plastic to break down over time as well. These fats can cause discoloration and texture changes, which are reasons enough to replace the food containers, since we know that these are signs of degradation."
