Microbiological techniques

Because the aim of the control of residues is to prevent residues in food exerting an undesirable effect on humans, it would be elegant to use this biological effect as the detection principle. Hence, the detection of drug residues in edible animal products has traditionally been performed by microbiological techniques. 

The earliest methods for detecting antibacterial residues in food appeared in 1945-1948, soon after microbiological assays for the evaluation of antibiotics 687 

Owing to the variability in results of the early developed microbiological procedures, standardized materials were introduced and are currently used for routine quality control. Depending on the format of the test, the presence of an inhibitory substance is indicated by zones of growth inhibition or a change in the color of the medium with pH and redox indicators. Examples of commercial 

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A recently published book provides an excellent survey of issues that relate to contamination with endotoxins (present in both viable and nonviable bacteria), their released cell wall constituents, and also viable bacteria in the pharmaceutical industry [1]. It is important to know both the content of the work environment (e.g., indoor air) and the pharmaceutical products themselves. The former provides information on possible sources of microbial contamination and the latter the purity of the final commercial product (or precursors in various stages in its preparation). In some cases it is vital to know the actual bacterial species involved in contamination culture-based methods are standard microbiological techniques which were the focus of Jimenez [1] and thus will not be discussed further. Any contamination (e.g., with endotoxins), regardless of the species of origin, is of utmost of importance (e.g., in determining the safety of a batch of antibiotics to be administered intravenously). This is determined optimally by non-culture-based methods. 

Vitamins are generally assayed in one of two different ways. The first route uses a microbiological technique. Here, a specialist organism is used, the growth of which is dependent on the concentration of the particular vitamin of interest. 

Analyses were performed in an external lab using conventional standard microbiology techniques... 

As a myriad of different and distinct species of microorganisms may exist in any given ecological sample, it is difficult to determine the total number of different species present using standard microbiological techniques. A multitude of selective media may be required and dormant spores or bacterial cysts present in the sample may develop on the laboratory medium giving the investigator a false impression of which species were most active. 

In summary, it is extremely difficult to evaluate processes such as biological conversions of minerals using current microbiological techniques. Hence biological contributions to the cycling of sulfur have been estimated by the bulk behaviour of systems. The flaw in this approach is that biotic and abiotic processes are not delineated to the extent desirable. 

Bml, S., Coote, P., Oomes, S., Mensonides, F., Hellingwerf, K., and Klis, F. 2002a. Physiological actions of preservative agents Prospective of use of modem microbiological techniques in assessing microbial behavior in food preservation. International Journal of Food Microbiology 79 55-64. 

Despite the arrival of rapid genetic as well as immunological techniques for the detection of foodborne pathogens, evaluation of the microbiological quality and safety of foods is usually done in retrospect and is not in reality effective in protecting consumers from foodborne hazards. There still exists a predictive approach. As a result, predictive modeling has developed as an addition to traditional microbiological techniques (Mellefont, McMeekin, and Ross, 2003). 

Determination of Bioburden Estimates of bioburden are no better than the microbiological techniques used for their determination. There is no single standard approach for dosage forms for medical devices. Therefore all techniques tend to be particular, and generalizations ate difficult to make. 

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