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
Best Answer
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°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.
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What are the effects of thawing?
Changes which take place during the thawing processes of frozen meat include the growth of microorganisms, weight loss due to drip loss, and color change (Berry, 1994; Kondratowicz et al., 2008), effect of WHC (Miller et al., 1980; Sebranek, 1979; Zhuang, 2012), increase of rancidity (Lannari and Zaritzky, 1991; ...What is the danger of thawing food at room temperature?
Never thaw food at room temperature or in warm water. Even though the center of a package may still be frozen as it thaws on the counter or in the warm water, the outer layer of the food is in the "Danger Zone," between 40 and 140\xb0F. These are temperatures where bacteria multiply rapidly.What would be the effect of freezing temperatures in food?
Freezing stops the growth of microorganisms; however, it does not sterilize foods or destroy the organisms that cause spoilage. A few organisms may die, but once thawed to warmer temperatures, these organisms can quickly multiply. Chemical changes affect quality or cause spoilage in frozen foods.What is the effects of freezing and thawing?
After several freeze\u2013thaw cycles, irreversible freeze\u2013thaw damage occurs and rock strength gradually decreases, which poses a great threat to the stability of geotechnical engineering in cold region5. As is known to all, the freeze\u2013thaw cycles have significant effects on the physical and mechanical parameters of rocks.Low Temperature Preservation and Processing
More answers regarding what are the effects of thawing food at low temperatures?
Answer 2
Try to avoid option-3 (unless you suspect the item is a hazard).
As an alternative, keep the food in the freezer (per SAJ14SAJ's suggestion) and contact your local Second Harvest http://www.2harvest.org/ or equivalent organization.
Answer 3
Best bet from experience, leave the item frozen and sell reduced. Thawing and refreezing changes food taste and consistency with most items. As far as health and safety goes if it stays out of the danger zone the entire time it should be fine. In the grocery industry however you have no idea what has happened to the item that was obviously moved by the customer. Did a kid handle it for an hour or so while parents shopped letting it sit in danger zone before being dumped in the most convenient cold area? This is a strong argument for tossing it and taking the loss.
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