Microbial control issues

However, disinfectant household cleaners are also more likely now to be mentioned in newspaper and magazine articles as contributing to the problems of antibiotic-resistant bacteria these tend to be reports in the popular press where all antimicrobial products tend to be mentioned, despite no demonstrated scientific link between the household cleaner disinfectants and the problem [172-174], As noted, disinfectant cleaners continue to have popularity, but given some of the trends in microbial control issues, they may be either more heavily regulated or limited in the future. 

The objective of the microbial monitoring program is to obtain representative estimates of the bioburden of the environment. When data are compiled and analyzed, any trends should be evaluated by trained personnel. While it is important to review environmental results on the basis of recommended and specified frequency, it is also critical to review results over extended periods to determine whether or not trends are present. Trends can be visualized through the construction of statistical control charts that include alert and action levels. The microbial control of controlled environments can be assessed in part on the basis of these trend data. Periodic reports or summaries should be issued to alert the responsible manager [13]. 

Aliphatic-Garboxylics. There are only two herbicides present in this class, trichloroacetate [76-03-9] (TCA) and dalapon [75-99-0]. These are used primarily for the selective control of annual and perennial grass weeds in cropland and noncropland (2,299). Dalapon is also used as a selective aquatic herbicide (427). Dalapon and TCA are acidic in nature and are not strongly sorbed by sods. They are reported to be rapidly degraded in both sod and water by microbial processes (2,427). However, the breakdown of TCA occurs very slowly when incubated at 14—15°C in acidic sods (428). Timing not only accelerates this degradation but also increases the numbers of TCA-degrading bacteria. An HA has been issued for dalapon, but not TCA (269). 

Over the last few decades, safety has become one of the most important topics related to food. From this view, quality control of vegetable raw materials has at first to cover the following issues natural and anthropogenic contaminants (e.g. heavy metals, pollution from industrial and private combustions, not professionally deposited waste products, radionuclides), residues of fertilisers (e.g. nitrate), plant-conditioning and plant-protective agents, filth, pests, the microbial status and the occurrence of microbial toxins. It is not possible to discuss all these aspects in detail however, with a focus on herbs and spices, two of them should be stressed more thoroughly. For further information, see [8]. 

The issue of bioavailability is further clouded by the physical characteristics of soil and the role of a possible mass transfer limitation. Soil constituents are not simply flat surfaces with free and equal access to all bacterial species. The formation of aggregates from sand-, silt-, and clay-sized particles results in stable structures which control microbial contact with the substrate (Figure 2.7). Discussion of sorption mechanisms and binding affinities must include the possible impact of intra-aggregate transport of the substrate. If the substrate is physically inaccessible to the microorganism then both desorption from soil constituents and diffusion to an accessible site are necessary. The impact of intra-aggregate diffusion on degradation kinetics has been modeled for y-hexachlorocyclohexane (Rijnaarts et al., 1990) and naphthalene (Mihelcic Luthy, 1991). 

During development of the manufacturing process, an experienced microbiologist should be consulted as to the potential for microbial contamination of the product. Issues may include the selection of appropriate pharmaceutical ingredients, the ability of the manufacturing steps to control microbial contamination, the validation of sterilization processes, the cleaning and sanitization of process equipment, the adequacy of... 

Struijk, C.B., Mossel, D.A.A., and Moreno Garcia, B. 2003. Improved protection of the consumer community against food-transmitted diseases with a microbial aetiology A pivotal food safety issue calling for a precautionary approach. Food Control 14 501-506. 

An important issue emerged from the results of experiments with 14C-labeled pyrene added to a pristine forest soil (Guthrie and Pfaender 1998) (1) extensive mineralization took place only in samples amended with a pyrene-degrading microbial community, (2) there was a substantially greater nonextractable fraction of label in soils containing either the natural or introduced microflora compared with an azide-treated control, (3) metabolites that could be released by acid and base extraction remained in the soil after 270 days of incubation. 

The field is introduced in the first chapter, which points out the complexity of the adhesion process involving multiple adhesins on a single microbe and their respective target receptors on host cells, and discusses the possibility of controlling bacterial infections via preventing the adhesion or invasion stages of microbial pathogenesis. The latter issue touches on a vision of an anti-adhesive therapy, which in our opinion receives some validation on the basis of the contributions collected herein. 

Another important issue is that of the proper control variables. We have just alluded to the possibility of viewing microbial response as a resource allocation problem. The resources might, for example, constitute only a critical resource such as ATP that is the primary source of energy for metabolic purposes. It is difficult to be any more specific about this issue at this inceptive stage of our work. 

The above is a partial list of frequent scale-up issues that arise in bulk drug processing with consequences of lower chemical yields, or worse yet, loss of control over the impurity profile, as well as slower processing, excessive damage to microbial cells and crystalline solids, undesirable particle size distributions and any from a wide range of assorted shortfalls in process performance. 

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