Ask the experts: Freezing food in plastic containers

Q: “I’ve received an email about the dangers of freezing food in plastic containers. Should I worry about this?”

A: No. There are a lot of plastic containers and bags specifically for use in food storage, including freezing. Meat in trays and commercial plastic wrap can be safely frozen as they are, but make sure you thaw meat at a cool temperature. Migration of DEHA from the wrap increases with heating in contact with a fatty food.

One email which keeps doing the rounds is attributed to Johns Hopkins University. The email says water bottles shouldn’t be frozen as they release dioxins. But on the University’s website, they disown this email and refute the claim.

Know your plastics

• DEHA: A food-compatible plasticizer which makes the plastic flexible. Small amounts may migrate into food under certain circumstances.
• PVC: Commercial plastic wraps made from PVC contain DEHA.
• Polyethylene: Plastic wrap we buy for home is usually made from microwave-safe polyethylene.
• PET: Most plastic water and soft drink bottles in New Zealand are made from PET which does not contain DEHA.
• Polycarbonate: A plastic often used in refillable water bottles and baby bottles.