Essential Guidelines for Freezing and Thawing
According to UNSW microbiologist Associate Professor Julian Cox, freezing food doesn’t kill bacteria. While freezing can reduce bacterial numbers, improper thawing can lead to rapid bacterial growth. He explains, “If bacteria were present before you put food in the freezer, they’ll still likely be there when you thaw it.” This highlights the importance of proper food handling and storage techniques to prevent foodborne illnesses.
Julian Cox emphasises the need to cool meals in the fridge before freezing them. “Avoid putting steaming hot food straight into the freezer because you risk partially thawing the food around it and potentially giving bacteria a chance to start growing in those foods,” he advises. Fridges handle heat better than freezers and reduce the chance of bacteria growing compared to allowing food to cool at room temperature.
Ensuring food safety involves more than just freezing. Domestic freezers create larger ice crystals than industrial ones, affecting the overall quality of the food. Foods frozen commercially use blast-freezing techniques that minimise ice crystal size. “If food is thawed and refrozen, this damage increases and overall quality drops significantly,” Cox notes.
Practical Tips for Safe Freezing and Thawing
For best results, thaw food in the fridge or microwave, not at room temperature, to avoid bacteria growth. Foods thawed and refrozen face increased damage and diminished quality, making them more vulnerable to bacterial growth. Freeze food in small portions using airtight containers to maintain quality.
Imported frozen berries should be heated to at least 80 degrees Celsius before consumption to ensure safety. While freezing may slow or halt bacterial activity, it doesn’t eliminate all pathogens. Some bacteria, including Salmonella, can survive for long periods in frozen food, especially if the food is high in fat and protein.
Associate Professor Cox advises establishing a cold chain quickly. “If meal plans change, food stored in the fridge for a day or two can still be safely frozen,” he says. This flexibility helps households manage food storage more effectively.
To minimise food waste, it is essential to understand the impact of freezing and thawing on food safety and quality. Freezing meals not only saves time and money but also reduces food waste, which is a significant concern in many households.
For more expert advice on food safety practices, visit UNSW’s website. These guidelines are crucial for preventing foodborne illnesses and ensuring that meals are both safe and enjoyable.
