We were asked the simple question “When receiving frozen food, what is the acceptable temperature?”

I could give a very simple answer of “below -10°C” and leave it at that.

But there are a number of issues you should also consider:

1. How do you measure the temperature? If you are using an infra-red thermometer then be aware that you are only measuring the surface temperature of the item which is more of a reflection of the air temperature and not the product temperature. A better option is a probe thermometer but then that compromises the product. Ideally you want to unpack the product slightly and take a temperature reading inside the packaging.

2. Just because the product is too warm when you receive it, how long has it been too warm? Warm air temperature may be due to the vehicle doing a couple of deliveries immediately before your location, or it may be because the goods were too warm for too long.

3. What was the temperature throughout the transportation of the items? Transport is a recognised point of compromise in the supply chain. The quality of the refrigeration in a vehicle, the amount of time the doors are opened, and the large change in stock levels all contribute to the temperature of the items being compromised in transit. If you ever have a supply issue with transport, consider putting a temperature logger in with the goods to see what is actually happening.

4. Variation in temperature can be just as damaging to the quality of items such as ice-cream. Other items aren’t compromised as much.

So while there is a simple answer, I would also just back it up with the more important question “how do you monitor the temperature?” I would strongly argue that you need to:

The next question is “what do we do if the temperature isn’t acceptable when we receive it?”

My personal recommendation is to then do invasive testing. Open a sample to see what is happening inside. Use a probe thermometer to get into the product and take a number of readings. It’s probably better to destroy one sample finding out more information than rejecting an entire load.

And the final question is “what can be done to limit the problem in the future?” and I will leave that one for a future blog.