Food Safety Issues/partially thawed/refrozen food
When I buy frozen food at the grocery store (frozen dinners, pizza, etc), sometimes it takes so long to get through the checkout line and get home, that the food is partially thawed, especially if the weather outside is warm. Then the food is put in the freezer and fully frozen again, but how does this affect the quality or taste of the food, or does it? Thanks
First...Happy New Year!
The very nature of freezing will change the taste, color and texture,to some degree, in all foods. Some foods have better freezing outcomes than others and thus the foods that have been tested for the best retention of taste, color and texture are the ones you see frozen at your local grocery store.
Of course, the grocery store is not set up to encourage shoppers to shop the store in a way the will maintain the highest quality and safety of foods. They are set up for the highest potential profit to the store. Because of this, perishables and frozen foods are often placed in the cart before shelf-stable items.
If foods are partially defrosted during the shopping and transporting to home before being placed in the home freezer, the most common form of quality degradation can occur due to defrosting water being refrozen. This can lead to the formation of freezer burn -- a condition which produces a glassy appearance in some frozen products produced by ice crystals evaporating on the surface area of a product. Eventually grainy, brownish spots can result on the product causing the tissue to become dry and tough and to develop off-flavors. Freezer burn is not unsafe to consume but definitely affects the taste and quality of the product.
The good news is that the quicker that you get your frozen foods into your freezer (that is operating at 0 degrees F or lower) the less off flavors and texture changes will develop. In addtion, as long as the frozen foods still have ice crystals present (they have not fully defrosted) it is safe to refreeze. The faster you can get from grocery store freezer to your home freezer, the higher the quality of the product.
I encourage you to shop for frozen foods last and then place them in a cooler in your car, especially during warmer months, for the ride home. This is about all one can do to keep down the minimal thawing that occurs between the store and home.