Foods microbial control

One of the reasons why it is important to remove suspended solids in water is that the particles can act as a source of food and housing for bacteria. Not only does this make microbiological control much harder but, high bacteria levels increase the fouling of distribution lines and especially heat transfer equipment that receive processed waters (for example, in one s household hot water heater). The removal of suspended contaminants enables chemical treatments to be at their primary jobs of scale and corrosion prevention and microbial control. 

The inefficiency of microbial heterotrophy does have a side benefit as it enhances nutrient remineralization rates. This serves to increase the availability of inorganic nitrogen and phosphorus for the photoautotrophs. The multiple roles of bacteria in the marine food web were shown in Figure 23.2, with the component of the food web controlled by the algal herbivores depicted on the left side and the microbial loop on the right. The viral shunt acts on both pathways. 

Koseki, S. and Isobe, S. (2006). Effect of ozonated water treatment on microbial control and on browning of iceberg lettuce (Lactuca sativa L.).. Food Prot. 69,154-160. 

It is essential that FF-RMs are as similar as possible to the real samples as also holds true for other CRMs, e.g. environmental samples [7], This is often not possible due to very complex and delicate food and feed matrices especially as CRMs must show stability over a certain range of time. In food safety and quality, CRMs play an important role in the analysis of e.g. food microbial contamination, food contaminants such as mycotoxins, dioxins, polychlorinated biphenyls (PCBs) and food residues such as veterinary drug residues (hormones, antibiotics) and pesticides. CRMs for food quality control are important for analysis of food constituents such as fat, sugar and protein content or of typical indicators for the food origin (e.g. stable isotopes in wine). In addition, FF-RMs are used in proficiency testing, although most of this testing is done with non-certified assay materials (PTMs). 

Cutter, C. N. 2002a. Microbial control by packaging A review. Critical Reviews in Food Science and Nutrition, 42 151-161. 

Kvenberg, J.E. and Schwahn, D.J., Use of microbial data for hazard analysis and critical control point verification food and drug administration perspective, J. Food Prot., 63, 810, 2000. 

Dextran is the first microbial polysaccharide produced and utilized on an industrial scale. The potential importance of dextran as a structually (and property) controlled feedstock is clearly seen in light of the recent emphasis of molecular biologists and molecular engineers in the generation of microbes for feedstock production. Dextran is employed as pharmaceuticals (additives and coatings of medications), within cosmetics, as food extenders, as water-loss inhibitors in oilwell drilling muds and as the basis for a number of synthetic resins. 

The Centers for Disease Control (CDC) in the USA has estimated that Campylobacter and Salmonella are the top two bacterial foodbome pathogens as they are responsible for a total of 2 and 1.3 million foodbome infections every year (Mead et al., 1999). Most of the cases of infection with Campylobacter and Salmonella appear to be due to eggs and poultry, but a significant number of cases are related to beef products (CDC, 2005 Jay, 2000). EHEC does not cause as many infections as the top two pathogens (approximately 100,000 in the USA), but EHEC is frequently linked to outbreaks of diarrhea caused by the consumption of contaminated ground beef (Mead et al., 1999, Rangel et al., 2005). Infections caused by EHEC are the major microbial public health concern related to ruminant food products. 

USDA (2001) Analysis and Evaluation of Preventive Control Measures for the Control and Reduction/Elimination of Microbial Hazards on Fresh and Fresh-cut Produce. US Food and Drug Administration, Center for Food Safety and Applied Nutrition, September 30, 2001. www.cfsan.fda.gov... 

After all the answers from the interviews had been uploaded, an expert analysed each supply chain for each of the seven defined criteria for quality and safety microbial toxins and abiotic contaminants potential pathogens natural plant toxicants freshness and taste nutrient content and food additives fraud social and ethical aspects. For example, an expert on freshness and taste would check each major step in a supply chain for tomatoes to determine if it fulfilled the definition of a CCP (HACCP, Principle 2) in relation to freshness and taste for this commodity. If the step was considered to be a CCP, the answers in the questionnaire that related to relevant substeps at this step would be reviewed, to assess the control procedures that were in use for this CCP. The expert would then fill in the text field, structuring the input to consist of the following points ... 

An alternative packaging is the combination of food-packaging materials with antimicrobial substances to control microbial surface contamination of foods. For both migrating and nonmigrating antimicrobial materials, intensive contact between the food product and packaging material is required and therefore potential food applications include especially vacuum or skin-packaged products (Vermeiren and others 2002). 

Ruiz-Cruz S, Luo Y, Gonzalez RJ, Yang T and Gonzalez-Aguilar GA. 2006. Acidified sodium chlorite as an alternative to chlorine to control microbial growth on shredded carrots while maintaining quality. J Sci Food Agric 86(12) 1887-1893. 

This gum was the first microbial gum to be used in the food industry. It is produced by the aerobic fermentation of Xanthomonas campestris. A specially selected culture is grown on a carbohydrate-containing nutrient medium with a nitrogen source and other essential elements. The pH, temperature and aeration are controlled carefully. The product is then sterilised and the gum is precipitated with propan-2-ol. Next, the precipitate is washed, then pressed to remove residual alcohol, followed by drying and grinding to the required size. 

Diazinon (phosphorothioic acid 0,0-diethyl 0-(6-mcthyl-2-(l-mcthylcthyl)-4-pyrimidinyl) ester) is an organophosphorus compound with an anticholinesterase mode of action. It is used extensively to control hies, lice, insect pests of ornamental plants and food crops, as well as nematodes and soil insects in lawns and croplands. Diazinon degrades rapidly in the environment, with half-time persistence usually less than 14 days. But under conditions of low temperature, low moisture, high alkalinity, and lack of suitable microbial degraders, diazinon may remain biologically active in soils for 6 months or longer. 

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