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Hygiene and Microbiology - Module 1

This module informs about hygiene in terms biological contamination control and introduces into the world of microbiology. Knowledge in biology of microorganisms is a key in the understanding of hygiene measures like hygienic hand disinfection and decontamination of surfaces. We recommend to study the slides presentation of the module first, as it provides the basics on food hygiene, hygiene management, and microbiology. For students and apprentices, the presentation is available as a PDF file. Teachers should have a look at the summary of didactical components before downloading the original PowerPoint presentation from the restricted area. When you have used the module, we would appreciate your feedback submitted in the online evaluation form. Filling in the module evaluation form will help to improve the quality of the training course. Definitions

Hygiene management

A number of factors are important considering the general hygiene in food establishments, such as ventilation, humidity, susceptibility of the foodstuffs, and the general health condition of personnel. The general health status is for instance worse in winter time, so that certain measures might be required to reduce the spreading of pathogens in that period of the year. Taking those factors into consideration, a specific hygiene plan has to be developed which defines how often cleaning and disinfection measures have to be performed, which type of cleaners and disinfectants to be used etc. A hygiene plan will always be hand tailored for a certain area. Hence a hygiene plan for a bakery will be different from a hygiene plan for a meat processing factory. To determine the level of hygiene measures one has to be aware of the hazards that arise from handling particular foodstuffs. One of the hazards are those caused by microorganisms, which can be estimated due to experience from similar establishments or by taking samples at the production site. One could take an initial microbial sample in order to determine the type and the number of bacteria and fungi present. As the introduction of HACCP requires regular sampling, often 4 times per year, initial samples can be employed as a proof for the efficiency and appropriateness of hygiene measures.

Hygiene of personnel

From a scientific point of view it is beyond doubt, that hands play a major role in the spreading of microorganisms and the spreading of diseases. Molecular biological studies showed that germs are able to travel by handshakes and that they could be detected on other person's hands after more than five successive handshakes. Reduction of the skin flora obviously is an important hygiene measure. 

Hygienic hand washing

In general, it has to be conducted before and after breaks (e.g. canteen), after going to the toilet, after contact with contaminated areas or foodstuffs, and also after wiping one’s nose. Commonly, hand disinfection means that an alcoholic hand disinfectant is rubbed onto the hands. Preferably, one should apply an aliquot of alcoholic solution that lasts on the hands for at least 30 seconds until complete evaporation. Persons with open wounds should protect this area with water proof bandage material, so that remaining skin surfaces can be disinfected. Because of the high numbers of microorganisms on hand surfaces, and because hands touch a number of surfaces which should be kept free from germs, hygienic hand disinfection is the most effective hygienic measure to reduce the microbial load in food premises. Even healthy persons have to perform hand washing and disinfection because they are carriers for pathogenic germs without being effected by them. Although extremely efficient, many employees actually “forget” to perform hand disinfection procedures. The reasons for non-performance might be manifold, e.g. because

Hence, one of the most important tasks in hygiene management is not to provide hand disinfection products, but to change behavioural patterns. Audits have shown that education and information increase the awareness of risks, and better and more regular execution of hygienic hand washing and disinfection. The image shows the difference microbial cleanliness, between good and bad performers of hand washing procedures. The microbial load could be reduced furthermore using disinfectants!