FOOD SAFETY SUPPLEMENT: HYGIENE


MICROBIAL LIMITS USED FOR VARIOUS TYPES OF FOOD PROCESS SURFACES


BASED ON CASE STUDY EVALUATIONS


Gun Wirtanen & Satu Salo VTT Expert Services


In a hygiene survey, the hygiene level in a food factory can be seen from statistics drawn from results classified as good, adequate and poor hygiene level. At the moment, the risk management team in the food factories have to set the limits for the hygiene levels in their food factory based on the products produced and the shelf-life set for these products. In this study, microbes were detected on both contact and environmental surfaces using 3M™ Petrifilms for aerobic bacteria, fungi and coliforms. The samples were taken after cleaning, just before the work shift started, which means that at least the contact surfaces should be of good hygiene level. The limits for the various microbes were set in three scales (loose, normal and strict) for the three levels (good, adequate and poor hygiene level) using real results from 10 food factories in Finland, Estonia, Turkey and Romania. The aim of this study is to show the effect of various limits on hygiene surveys performed.


The quality control methods are used more and more for preventing risks that can occur in food during processing1


www.newfoodmagazine.com . Temperature, pH and


storage time are relatively easy to measure and adjust, but cleanliness of food contact surfaces as a control point is challenging. Measurement


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of the microbial load on the surfaces is mainly carried out using various microbial culturing methods with either swabs or contact agars. An international collaboration test showed that the recovery of microbes on surfaces is approximately 10 – 15 per cent, independent of the method used2,3


. However, the major


disadvantage of the culturing methods is the incubation time, which can be three to five days in room temperature and even 7 -10 days in cold temperatures, to reach results on which corrective actions can be carried out. There is also a need for support in the interpretation of results. What limits should be set for various types of surfaces and how should the surfaces be classified is not clear either. In most food


newfood Volume 15 | Issue 1 | 2012


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