Food Safety Analysis, LLC


Laboratory Testing Strategies and Review

Laboratory testing is a critical part of food manufacture. To take a "simple" example, the measurement of pH is often critical for food manufacture, especially when reaching a certain level of acidity may mean the difference between product spoilage or stability. For many, measurement of pH is merely a matter of introducing pH probes into a sample and recording the reading from the pH meter's dial face. The meter may be calibrated, according to instructions, using prepackaged "standard" buffers. However, how many food manufacturers are aware of the contributions to the final pH reading made by a sample's temperature, ionic strength, water activity, hydrophobicity and the presence of adsorbed, unstirred layers on the surface of the pH electrodes? How many food manufacturers realize that the most consistent approach to the pH measurement of foods is not necessarily to spend money on the most expensive pH meter one can find? Oftentimes, the best solution is to manufacture one's own "standard" buffer to deliver precisely the pH that the production process uses as its critical pH breakpoint. Repeated measurement of this known quantity provides a quality-control check on the operational status of one's pH meter in the same region where readings are most important. More importantly, the decision of whether or not a sample is above or below a critical pH value is no longer dependent upon the performance, that day, of your pH meter calibrated between two or three, widely-spaced standardization points. That question may now be answered simply by asking whether or not the observed sample reading is above or below the reading given by the custom-made reference buffer.

Similar considerations hold when utilizing outside laboratories. Is the method being used appropriate to the problem being investigated? Are the analytical sensitivities adequate for the question being investigated? If they are too low, an adequate answer is impossible. If they are set too high, money is being wasted on precision not relevant to the issue at hand. What controls does the laboratory have in place? What is their history and record on proficiency testing? Are their certifications relevant to the issue at hand? Have they explored possibilities to answer the question at hand better, faster and/or cheaper? What are their quality control procedures? Are their quality control parameters stable or do they drift? If the latter is true, has the cause of QC drift been identified and/or dealt with?

Many people in the business of manufacturing food are not themselves laboratorians and so cannot be expected to formulate the pertinent questions of the laboratories they send their samples to. In consequence, because food manufacturers don't have a clear understanding of the quality of the labs they use, they tend to see all laboratories as equal and search out and choose testing capability based only upon price, which exacerbates the issue.

As a result, client and service laboratory quickly establish an unquestioning routine that is itself not reviewed until there is a problem. Then an outside regulator begins asking the pertinent questions that the food manufacturer neglected to ask of the laboratory being used. After the immediate issue is resolved one way or the other, the regulator may (or may not) ask the question that the newly-discovered and obvious (to hindsight) lack of oversight suggests: "How could this manufacturer have paid for a service for so long without knowing what they were buying?" This is an uncomfortable lesson for a food manufacturer to have to learn from a regulator. The best advice to a food manufacturer may be not to even try to get comfortable sitting down on a hot seat.

Copyright © 2012 by M. Mychajlonka, Ph. D.