To quote one of the founding fathers, “In this world nothing can be said to be certain, except death and taxes.” Though not a microbiologist by trade, Benjamin Franklin’s wise words resonate all the way to the interpretation of your microbiology test results. It is academically and universally recognized that no microbiological measurement is perfect due to statistical and practical uncertainty. In fact, acknowledging the uncertainty of a measurement is as important as the measurement itself.
Uncertainty is even more complex in food microbiology due to the particulate nature of bacteria and their ability to reproduce by binary fission. This results in localized pockets of higher concentrations of bacteria where each individual represents a unique variable entity. Consequently, there is an uneven distribution of microbes even in well-mixed samples that create problems not only for test methods but sampling in order to get a meaningful result for the batch. The working group of the International Laboratory Accreditation Cooperation states “it is virtually impossible to know the exact microbial concentration in any sample, natural or artificial.”
The vagaries of microbial measurement are often conveniently forgotten, resulting in unreasonable expectations of both laboratories and the methods deployed. So what do microbiological test results actually mean? What can be expected and do expectations apply equally to both product and environmental samples?
Food products are generally well controlled and manufactured to a consistency where microbial specifications are established. Conversely, there are no agreed standards for microbes for environmental surface samples that are less controlled and more variable. Each facility is expected to do “the best it can” for monitoring cleaning processes due the uniqueness of each manufacturing facility. Thus food manufacturers strive for high hygienic standards to protect their products, brands, and ultimately consumers.| | | Next → | Single Page