Process to slowly raise the temperature of Chocolate Liquor Discs
I need some guidance on a task that a customer is asking our company to accomplish for them. They have a couple pallets of chocolate liquor discs that were mistakenly frozen by a carrier during transit from another warehouse. They have asked us to help them by slowly raising the temperature to an acceptable temperature range of 55F-65F in order to try and salvage the product w/o any cosmetic issues.
My question is, what would be the best process to slowly raise the temperature of this product if it is brought to our refrigerated warehouse at frozen temperatures? We have space that is -5F (Quick Freeze Racking), 0F, 36F, 40F, 55F, and Dry. We also have the capability with quick thaw racking (40F) and spacers. According to the customer this is a high level issue and carries a significant cost if they can't salvage the product. Any help or insight is appreciated!
What is the FDA definition of adulteration in this case - I assume they need them thawed without cosmetic issue in order to pass them off as never having an issue?
Correct. I feel there wouldn't be any food safety issue. It's a quality issue where they want to prevent the formation of the pasty white sugar residue due to the product warming too quickly.
The pack size and type? This makes a difference.
If they have the time and you have the space, break out the pallets by each unit of pack and space appropriately to allow air flow around the unit. I'd put them in the 36 degree and give it a week. You'll need to open one of the units to determine if it needs more time to thaw or not; take a sample from the center of the pack.
If thawed, move to the 55 degree and provide proper spacing. Give it another week and repeat sampling process to check the temperature and quality. Once it reaches around 55 degrees put it in the dry warehouse and space it out by unit. I don't know what your dry warehouse temperature is, but this will impact the quality of the product.
If you don't have the space for this process, consider using a trailer with a refer unit, or you can rotate the units on the pallets to help even out the temperature changes for all units.
If the sole aim is to raise the temperature as sedately as possible then the primary point to note is that rate of temperature change is generally proportional to the temperature difference.
If you're a fan of calculus then the rate of change could be described by something like dT/dt = k(T1-T2).
The slowest way to raise the temperature would therefore be to do a stepped progression through your various storage options, starting with 36°F and then on through 40°F, to 55°F, to ambient.
As per Ryan M's suggestion, you want to spread out the stock as much as possible as this will help ensure even temperature change across all the stock - otherwise outer boxes on pallets will insulate the stock in the middle.
You can monitor the temperature daily or similar to decide when to move to the next phase.
Doing it this way may be a bit excessive - Ryan M's suggestion of fewer steps may be a pragmatic compromise - so probably one to discuss with the customer as they are the one who will (should?) understand their product best.