4 replies to this topic

[sinush03]

Hi,

 

How do I answer this?

 

"The acceptable tolerance for each calibration measurement equipment hasn't been determined, which not able to verify the results of calibration whether the status of measuring equipment still in the good condition or adjustment needed if necessary."

 

Recently got audited by FSSC auditor, and above is one of the NC. However, I am not quite understand on how to answer it. We registered large equipment for external calibration and weighing scale for internal calibration. The auditor saw one of the calibration certification, example: Setting 200°C, but calibrated result shows 200.1. Then he asked, what is your tolerance limit.

[Evans X.]

Greetings,

 

You have to set the upper and lower acceptance limits of the set values you have for temperatures or weights, anything you calibrate. In your case, you should state somewhere in your SOPs that for example the desired working temperature is 200 ± 1^oC, so the 200.1 is within the acceptable working limits. Same goes for weights/ scales etc.

The limits can be backed up by literature or internal experimentation. At this temperature even a ±5 won't do much difference, but in lower thermal threatments eg pasteurization at 72^oC/12sec even a ±1 may be a huge problem.

Bottomline is that you have to set limits from which if your over or under you may have an equipment malfunction and can possibly lead to an unsafe product.

A step further is to monitor the trend also. Usually you need your calibration measurements to be evenly spread over and under the 200 mark, always within the acceptable limits. Even if you are every time within the limits but lets say always on the lower tier then this can also indicate a possible problem with the equipment.

 

Regards.

[sinush03]

Greetings,

 

You have to set the upper and lower acceptance limits of the set values you have for temperatures or weights, anything you calibrate. In your case, you should state somewhere in your SOPs that for example the desired working temperature is 200 ± 1^oC, so the 200.1 is within the acceptable working limits. Same goes for weights/ scales etc.

The limits can be backed up by literature or internal experimentation. At this temperature even a ±5 won't do much difference, but in lower thermal threatments eg pasteurization at 72^oC/12sec even a ±1 may be a huge problem.

Bottomline is that you have to set limits from which if your over or under you may have an equipment malfunction and can possibly lead to an unsafe product.

A step further is to monitor the trend also. Usually you need your calibration measurements to be evenly spread over and under the 200 mark, always within the acceptable limits. Even if you are every time within the limits but lets say always on the lower tier then this can also indicate a possible problem with the equipment.

 

Regards.

Thank you for answering!

 

Regarding the limits, is there any calculation/formulation that can be refer to? By the way, I'm in bakery industry, so if say like, the measured temperature by calibration is higher, 204, what kind of correction that we can opt to?

[Evans X.]

For the calculation/formulation part you have to do a bit of research, regarding your industry. The temperature along with the baking time are already high enough to be a sufficient kill step, but then there might also be quality issues that you need to consider. For example and to answer your question, if you exceed 204 you will not have a micorbiological problem, but the product may dry up and become like a rusk or blackened which are quality problems. The correction might be a reconsideration of what you are going to do with the problem, maybe indeed go for making rusks (?) or discard it and the corrective action is to check the thermal control of the oven (maybe some maintenance is in order).

On the other hand if it is lower than lets say 196 then you may have moisture left in the dough and the possibility of having a good environment for moulds to grow.

Correction is discarding maybe (?) and corrective action same as above.

[sinush03]

For the calculation/formulation part you have to do a bit of research, regarding your industry. The temperature along with the baking time are already high enough to be a sufficient kill step, but then there might also be quality issues that you need to consider. For example and to answer your question, if you exceed 204 you will not have a micorbiological problem, but the product may dry up and become like a rusk or blackened which are quality problems. The correction might be a reconsideration of what you are going to do with the problem, maybe indeed go for making rusks (?) or discard it and the corrective action is to check the thermal control of the oven (maybe some maintenance is in order).

On the other hand if it is lower than lets say 196 then you may have moisture left in the dough and the possibility of having a good environment for moulds to grow.

Correction is discarding maybe (?) and corrective action same as above.

 

Usually, If there's variation in calibration result, can calibration service adjust the temperature of equipment (cold room, baking oven, etc)?