Checking frozen incoming material using digital probe thermometer

Hi, may i know how to check core temperature using probe for frozen surimi?

How do you guys put the probe inside the surimi block?

Thank you.

Greetings Fara.

On a given product that is frozen for days it's not the core that you should worry so much about but the surface, as it is the first part to start thawing.

Using the probe is difficult, since you need to find an opening. DON'T create an opening though as it may become a cross-contamination point if not properly done (disinfected tool, specific diameter so as not to have false readings, product destruction etc).

The other option is using an infra-red thermometer, but you need to be careful when using it and follow the instructions to the letter for accurate measurements (take into consideration things like angle, distance, mirroring surface etc).

Another interesting option is the use of a thermocouple. It may require a bit more equipment-wise but it does the job.

Regards!

you can get flat surface probes- you place it between two blocks so you do not pierce the inner packaging

Greetings Fara.

 

On a given product that is frozen for days it's not the core that you should worry so much about but the surface, as it is the first part to start thawing.

Using the probe is difficult, since you need to find an opening. DON'T create an opening though as it may become a cross-contamination point if not properly done (disinfected tool, specific diameter so as not to have false readings, product destruction etc).

The other option is using an infra-red thermometer, but you need to be careful when using it and follow the instructions to the letter for accurate measurements (take into consideration things like angle, distance, mirroring surface etc).

Another interesting option is the use of a thermocouple. It may require a bit more equipment-wise but it does the job.

 

Regards!

you can get flat surface probes- you place it between two blocks so you do not pierce the inner packaging

I need to check the core temperature. 

I will do the devil's advocate here, but the auditor SHOULD backup his claim, based on legislation/ facts/ literature/ common sense/ anything at all, on why you should measure core temperature of a completely frozen product and not blind interpretation of the statement "a product's temperature should be measured at the core (geometric center)".

The only reason for checking it is if it has been frozen for less than a day, which I don't believe to be the case. Meaning that this is the only scenario that the product might not have frozen to the core, which then again might not be exactly a problem since the low temperature will already start slowing down the metabolic activity of any microorganisms as the freezing process starts from the outside.

If it has been in the freezer for more then you care more for the outside staying frozen, cause if there are flactuations and the product might go from frozen to somewhat thawed then again frozen due to mishandling, its the outer layer that can cause contamination and hold microorganisms. And there is no better contender than yeasts-molds in situations that moisture is present. Furthermore have in mind that if the surface is not at the desired temperature then this means that even temperature may at some point(-s) have reached close to optimal temperatures for microbial activities.

Also physics-wise, thawing starts from the outside to the inside, so the check point is the surface. If the surface is "half"-frozen the cross-contamination festival could begin and you wouldn't even care about the core.

A between pack probe every time.  Not IR, they're harder to calibrate.

This kind of thing:

Between Pack Probe (Thermistor) SX23L from Comark (comarkinstruments.net)

I need to check the core temperature. 

You really don't, and can't.  Why are you trying to?

I'd write a risk assessment and do some testing (using a drill to get into the core) to prove the point that surface is worst case scenario.  Core temperatures are for measuring cooking.  

I will do the devil's advocate here, but the auditor SHOULD backup his claim, based on legislation/ facts/ literature/ common sense/ anything at all, on why you should measure core temperature of a completely frozen product and not blind interpretation of the statement "a product's temperature should be measured at the core (geometric center)".

 

The only reason for checking it is if it has been frozen for less than a day, which I don't believe to be the case. Meaning that this is the only scenario that the product might not have frozen to the core, which then again might not be exactly a problem since the low temperature will already start slowing down the metabolic activity of any microorganisms as the freezing process starts from the outside.

 

If it has been in the freezer for more then you care more for the outside staying frozen, cause if there are flactuations and the product might go from frozen to somewhat thawed then again frozen due to mishandling, its the outer layer that can cause contamination and hold microorganisms. And there is no better contender than yeasts-molds in situations that moisture is present. Furthermore have in mind that if the surface is not at the desired temperature then this means that even temperature may at some point(-s) have reached close to optimal temperatures for microbial activities.

Also physics-wise, thawing starts from the outside to the inside, so the check point is the surface. If the surface is "half"-frozen the cross-contamination festival could begin and you wouldn't even care about the core.

So we don't need to check the product core temperature if we feel the product is hard because we know it is frozen? 

How do we need to record/document it for incoming inspection?

do i just need to put 'surface temperature' instead of 'core temperature' or just 'temperature' for the temperature section?

I think maybe this is one of the reasons why he questions the way i take the temperature of the frozen surimi because i stated there 'core temperature' but i don't do what i write. 

Yes, you are right in that. The rule is "Write what you do and do what you write".

Always taking into consideration though that what you write is based on legislation/ GMP/ literature/ facts !!!

Yes, you are right in that. The rule is "Write what you do and do what you write".

Always taking into consideration though that what you write is based on legislation/ GMP/ literature/ facts !!!

So is it possible for me to change the term for the temperature section?

And is it okay if we don't take core temperature to check the temperature of the frozen raw material?

i will state in the HACCP plan summary that our critical limit is -18C based on surface temperature and my corrective action is we would drill the surimi block until the core if the temperature of the surface doesn't achieve -18C.

What is your opinion?

As others have described, if you're starting with an item that is supposed to be frozen you should be testing the surface temperature, because that it where it will become unacceptably warm first. 

If your program or document is calling for a "core temperature" on a frozen item, then the document is what needs to change, not discovering some way to insert a delicate thermometer into the center of a block of ice.

If you state your critical limit to be -18C and it fails to be -18C then it is unacceptable.  Taking a temperature somewhere else isn't going to change the failure to achieve your critical limit.  Perhaps this is another descriptive problem where below -18C is your quality goal, but your critical limit is supposed to be -4C?

Do you mind to share if there is any standard/journal that support your statement regarding the testing for product temperature for incoming frozen material can be test using surface temperature and doesn't need to check core temperature? (incase if my auditor ask for evidence to justify my changes)

Here i found - CODE OF PRACTICE FOR THE PROCESSING AND HANDLING OF QUICK FROZEN FOODS (CAC/RCP 8-1976) 

I need your opinion...

For HACCP Plan Summary i will change :

critical limit : ≤ -12 ˚C

Monitoring : - What : surface material temperature

                    - How : Using digital thermometer put in between surimi block

Corrective Action : If the temperature in between surimi block doesn’t achieve ≤-12°C, reject and return to supplier.

Yes, you are right in that. The rule is "Write what you do and do what you write".

Always taking into consideration though that what you write is based on legislation/ GMP/ literature/ facts !!!

Do you mind to share if there is any standard/journal that support your statement regarding the testing for product temperature for incoming frozen material can be test using surface temperature and doesn't need to check core temperature? (incase if my auditor ask for evidence to justify my changes)

Here i found - CODE OF PRACTICE FOR THE PROCESSING AND HANDLING OF QUICK FROZEN FOODS (CAC/RCP 8-1976) 

I need your opinion...

For HACCP Plan Summary i will change :

critical limit : ≤ -12 ˚C

Monitoring : - What : surface material temperature

                    - How : Using digital thermometer put in between surimi block

Corrective Action : If the temperature in between surimi block doesn’t achieve ≤-12°C, reject and return to supplier.