FAQs on Food Wrapping

Can I use plastic freezer bags to store produce in the fridge?

“For some products, heavy bags are okay, but not for others,” says food scientist Dr. Karin Allen.  “Fruits and vegetables in the fridge are still respiring (giving off gas), which causes them to rot.  Heavy bags won’t allow normal gas exchange—letting ethylene out and oxygen flow back and forth.  You want to maintain a delicate balance.  Also, heavy bags cost more, so don’t use them if they’re going to be harmful or not helpful.”



Are any plastic wraps or containers really “microwave safe”?

You’ll find answers that say “yes” or “no,” depending upon which Internet site you read. The fear is that chemicals used in making plastics (plasticizers) can migrate into the food. However, says food scientist Joe Regenstein, these are approved for that purpose.  Chemicals called dioxins are most feared since they’re known to be highly toxic. The opposing views on this subject may leave one feeling that more research needs to be done.  Meanwhile, you may choose to avoid microwaving plastics. At least, take these widely recommended precautions:


Are some plastic wraps more effective than others?

What sort of plastic is most effective depends on the job you want it to perform. Some films are impermeable to oxygen—this is what you want for high-fat foods if you want to prevent oxidation. Most are impermeable to water—this is what you want if you don’t want the food to dry out. Some are impermeable to certain wavelengths of light—this is what you want if you want to prevent color change and/or oxidation of fats and vitamins.

Can chemicals leach unto food from plastic wrap or containers?

Not when the food is going into the fridge. “The structure of plastic starts to break down with heating,” explains food scientist Dr.  Karin Allen.  “If you heat a plastic product, even one that’s BPA-free, it may leach.  If the plastic melts or warps, throw the food away.”


According to food scientist Joe Regenstein, many films have chemicals that are meant to migrate. They are safe and migrate more slowly in the refrigerator.


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