Sous vide, a popular method of cooking food sealed in plastic bags in a temperature-controlled water bath, has raised concerns about potential microplastics leaching into food. With the growing awareness of microplastics in our environment and food supply, many home cooks are wondering: is it safe to cook with plastic bags sous vide style? Let’s take a closer look at the current research and expert recommendations.
What the Science Says About Microplastics and Sous Vide
While there haven’t been studies specifically on sous vide and microplastics, some research has been done on how heat affects different types of food-grade plastics:
- A 2011 study found that most plastics on the market, even BPA-free ones, can release hormone-disrupting chemicals when heated. However, the levels released are unknown.
- A study on microplastics in fish cooked sous vide found that high temperatures above 65°C (149°F) promoted some polymer degradation in the plastic bags. The fish contained an average of 1.27 microplastic particles per gram.
- Research on BPA-free plastic food containers found that almost all of them leached chemicals with estrogenic activity, even without added stressors like heat. Exposure to these chemicals is a concern especially for fetuses and juveniles.
So in summary, the current evidence suggests that cooking in plastic bags, even food-grade ones, likely leads to some level of microplastics and potentially harmful chemicals leaching into food. However, more research is needed specifically on sous vide conditions to quantify the amounts and determine if they pose health risks.
Choosing the Safest Bags for Sous Vide
If you do cook sous vide, most experts recommend using high-quality, food-grade plastic bags that are BPA-free and made of polyethylene. Avoid using single Ziploc bags in water bath temperatures above 158°F as the seams can rupture. Either double bag or use vacuum-sealed bags designed for sous vide. Never use plastic wrap inside the bags.Some sous vide manufacturers are now making reusable silicone bags as a plastic-free alternative. Silicone is considered more stable and inert than plastic. However, research is limited on whether silicone bags are completely free of chemical migration under sous vide conditions.
Putting Sous Vide Microplastics in Perspective
While the possibility of microplastics from sous vide is concerning, it’s important to keep in mind that plastic contamination is now ubiquitous in the environment. Studies have found microplastics in tap water, sea salt, beer, honey, and many other foods. Exposure from sous vide is likely a drop in the bucket compared to our total consumption.That said, many health experts advise limiting plastic use with food as much as possible, especially when heat is involved. Cooking methods like grilling, roasting, steaming, and pressure cooking allow you to avoid plastic bags altogether. If you do choose to sous vide, use the safest bags, don’t overcook, and limit use to occasional meals rather than daily.
The Bottom Line
Based on currently available research, sous vide cooking likely leads to some microplastics and chemicals leaching into food from the plastic bags. While the health impact is still unclear, those concerned can minimize risk by using high-quality sous vide bags, silicone bags, or avoiding the method altogether. At the end of the day, the convenience and taste of sous vide should be weighed against potential safety concerns. More research is needed to fully understand the implications of microplastics from sous vide.