Microbiologic monitoring evaluation

An action level in microbiological environmental monitoring is the level of microorganisms that, when exceeded, requires immediate follow-up and, if necessary, corrective action. The evaluation does not depend on the number of colonies only but also on the types of microbes isolated and the suspected hazard. 

Fields, N. Oxbarrow, G. Puleo, J.R. Herring, G. Evaluation of membrane filter field monitors for microbiological air sampling. Appl. Environ. Microbiol. 1974, 27 (3), 17-520. 

There are three basic methods which have been employed for evaluation of microbiological content on surfaces. These include ROD AC (Replicate Organism Detection and Counting) plates, swab testing, and agar overlay or rinse techniques. RODAC plates are the most commonly used of the surface monitoring methods. However, they are not suitable for irregular surfaces, in which case swab techniques are used. 

Microtox can be used effectively for screening of new water supplies, pre- and post-treatment monitoring to evaluate the effectiveness of such treatment and to test waters transported often for long distances under difficult situations to confirm that they remain contamination free. It should be noted that Microtox will detect chemical contamination but will not [Rovide information on microbiological quality unless significant quantities of microbial toxins have been released. 

The colors were analyzed on a regular basis to evaluate stability, and microbiological contamination. Feed analyses were conducted on a weekly basis for the first 13 weeks of the study, and then at monthly intervals thereafter by the contract laboratory and by independent laboratories. Good laboratory practices monitoring occurred at least monthly. 

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