What are the effects of thawing food at low temperatures? Context: I am a member of staff at a supermarket where customers within supermarkets frequently "dump" refrigerated/fresh items into freezers. As far as I am aware, the options I have to me for dealing with these dumped items are as follows:


Thawing the (partially/entirely) frozen item within the back-area chillers and selling as normal
Thawing the (partially/entirely) frozen item within the back-area chillers and reducing the price of the item, as we currently do with lesser-quality food items (eg poor cuts of meat, superficially damaged packaging or multi-pack items that are missing an item or two)
Discarding the item as not-fit-for-human-consumption


Background reading indicates that for most products - assuming that the food does not defrost within the "danger zone" (above 40f) - the main concern with thawing these items relates to food quality rather than food safety as the freeze-thaw cycle will damage the food's internal cell-structure.

This leads me to believe that option #2 is the best balance for avoiding excessive wastage and ensuring customer safety but these thoughts are based on extremely limited reading material and passing the smell-test of what "makes sense". 

Please confirm the "best practices" / safety guidelines relating to this scenario and provide information on the caveats / what to look out for.

Many thanks
Not being in the grocery industry, I cannot advise you on what best practices are in your industry.

However, assuming you thaw the items in your chiller at safe temperatures (40&deg;F or below) as you indicated, you do not have a safety issue.

Depending on the product, there will be damage from ice crystals forming during the freezing, which will make meats more watery and degrade their texture, change the texture of vegetables, and so on.  This is more true than commercially frozen equivilent products, because slower freezing produces larger crystals which cause more physical damage.  Commercially frozen foods are often frozen in blast chillers to minimize freezing time and ice crystal size growth because of this problem.

I cannot give you specific information on what to look for in terms of quality degradation, because it would depend on the specific item.  Think about what would happen if you froze it at home in your own freezer, and thawed it for use later.  The same type of quality change will occur.  Vegetables will tend to get limp; meats will tend to exude more juice.  Of course, the consumer deserves to know that this has occurred.

Therefore, I think your best options are 2 (disclosing that the item was frozen).  You may choose to discard the item as not of a high enough quality, but it is still safe and fit for human consumption.

It may not be practical for you to store, but you could also let the item freeze completely, and sell it at a discount frozen, allowing the customer to thaw it at their convenience.

I applaud your ethical approach in actually asking.