We must be certain that the equipment we use to measure (for example, the amount of chemicals, the temperature of the cold room, or the concentration of the disinfectant in the wash tub), is performed correctly because this can cause safety, quality, and even economic problems.
Initially, when the equipment is new, the manufacturers are responsible for supplying them correctly calibrated, however, due to constant use, they lose the same measuring accuracy due to the natural wear of the equipment.
Therefore there are strategies such as calibration, verification, and adjustment that help us to restore the equipment to its initial conditions.
The terms mentioned above are similar and sometimes we use them as equivalents, but we will try to simplify them:
Calibration is comparing the values of an instrument with a measurement standard to determine its inaccuracy. This is what calibration laboratories normally do.
But what is a measurement standard? Well, a measurement standard is an instrument that has already been calibrated with another instrument and a series of uninterrupted steps until the international standard measurement is reached. This is what we call metrological traceability.
Now, what is uncertainty? In simple words, it is the estimation of those errors that may occur during measurements, due to the environment, the person performing the measurement, or even the instrument itself.
Verification is also the comparison of the values of two instruments, one of them calibrated; the difference is that it is not necessary to determine the value of the uncertainty. This can be performed in-house.
Finally, the adjustment. This is the adjustment that is made to the instrument to restore it to its original operating characteristics. Some equipment such as potentiometers have this function internally, such as balances are done manually or by a specialized technician, and in instruments such as test tubes, it is not possible to perform it.
During constant audits by Eleven Rivers Growers, this is a standard that is evaluated in equipment and instruments used for any stage of production from the field to the packaging and that may affect in any possible manner the food safety.
Edgar Saúl Ramírez Guerrero – Internal Audit Coordinator /Veggies From Mexico