Walk-In Refridgerator Thermometer

Does a Walk-In Refridgerator need to have an internal thermometer for temperature monitoring asides from the external thermometer?

This requirement is being suggested to be included in our Kitchen Food Safety Checklist. But I have questioned the rationale behind this. A mecury glass thermometer has ben recommended, but as far as I know, having a thermometer in the WIR is a no-no from a HACCP point of view i.e. Hazard of glass if it breaks or worse still mercury leaking off & geting into the food stored therein, likewise a digital batery operated thermometer has its inherent hazards too aside from the fact that the battery will cold-out in a matter of hours.

The reason for this requirement is because the sensor of the external thermometer is located in one corner of the WIR and they want to be sure that the temp is within requirement in other parts of the WIR. I was of the opinion that as long as the WIR is not overloaded and there is enough space for air circulation adn the cooling system is not covered or blocked, this shouldnt be an issue.

My argument so far has failed to persuade the Industrial Hygiene Dept.

Could anyone offer more convincing arguments I could raise?

Dear Theo,

The knowledge of a desired product temperature will depend on various factors and typically necessitates use of internal observations.

There is another thread on the forum discussing measurement of internal refrigerator temperatures. This includes a link to a commercial self contained (US I think) unit which can be placed anywhere in the refrigerator as required. Product was a package development of the manual method which simply uses a container of water with a calibrated thermometer in it. I think it claimed to hv substantial usage time, may not even hv used batteries (eg alcohol based), can't remember.

Rgds / Charles.C

Tnx Charles C,

Although cant seem to get onto the thread you mentioned.

Theo

Dear Theo,
Alcohol based thermometers are easily available for use in refrigerators and comes in protected case. You can refer to Fischer catalogue. I have used them.
Kind regards
Sujit

Dear Theo,

Here is the link with a picture, obviously thermocouple based. -

http://www.ifsqn.com...m...ost&p=24809

I hv no direct experience with battery life at 0-5degC. I thought the picture also had the source which wud maybe detail the function and offer a battery solution but seems not. Is Bets still around ??
A quick test would presumably be to, as per previous post (thks!), install a protected, calibrated, thermometer in the desired area as I described and periodically compare to the current external value. No significant difference = Good News. It depends how much is significant of course.

(Interestingly, if you are talking about packages like cartons and large volumes at much lower temperatures, eg -18degC, one standard surveyor method is to (quickly!) use thermocouple probes inserted (ie tightly sandwiched) between cartons. Surprisingly (to me anyway) reliable method though the home TC calibration is less easy IMEX .)

Rgds / Charles.C

added - I noticed this comment in the ESSORTMENT ref.in my post#9 in the top-linked thread -

Check the temperatures with a refrigerator/freezer thermometer that can be purchased at most grocery stores or kitchen outlets. A basic thermometer is around $5.00

.

Not too sure about the accuracy of the above but presumably safe.

At my old job I used these as backup checks for walk in refrigerators, even though designed for transport I found them very useful for all manner of temperature recording with the added advantage of logging the data for later review.