Water microbiological parameters

Fig. 8. Seasonal variations in microbiological parameters in the 0 to 1 cm horizon of a sandy-mud sediment (water depth 18m) of the Kiel Bight (Baltic Sea, FRG). Illustrated are total number of bacteria, total bacteria biomass and biomass spectrum. The biomass spectrum comprises small-size bacteria (volume < 0.3 m3 closed circles), medium-size bacteria (volume 0.3-0.6 jjm3 open circles), and large-size bacteria (volume > 0.6 yrr)3 crosses). For the headline on top cf. Fig. 7.

As regards food and water microbiology, current outbreaks in Europe have made apparent the necessity for official inspection agencies or ministry departments and for food industries or water agencies to get laboratories accredited quickly to perform tests in accordance with new test parameters, or to apply current methods to new ranges of food products. Accredited laboratories must be able to develop and validate new methods, or to derive methods from standards. Official recognition of these new test methods or their official incorporation into the scope of accreditation takes a long time, and audits are required for validation of these test methods. 

Testing the potential of pipe materials to promote biofilm growth is needed because it may affect the taste, odor or turbidity of drinking water and may cause non compliance with microbiological water quality parameters and a risk to consumers health. Because EU Drinking Water Directive (98/83/EC) controls the water quality at the consumers tap instead of the point of supply, it is important to be assessed if the pipe material in drinking water supply systems release substances that may enhance or inhibit attached microbial growth. 

Principles for drinking water directives Types of water covered by the DWD Parameters and parametric values Parameters in DWD 98/83/EC Basis of parametric values Microbiological parameters Carcinogenic parameters Other considerations Sampling and monitoring Quality control and assurance... 

Microbiological Parameter For Shellfish-Harvesting Water To Be Classified as Approved or Conditionally Approved For Shellfish-Harvesting Water To Be Classified as Restricted or Conditionally Restricted... 

The effluent obtained after solids removal and microbiological disinfection could be reused as cooling water, cleaning water or industrial process water in many industrial uses. A final polishing step may be necessary if higher quality requirements are needed in some specific industrial uses, e.g., cooling and boiler feed-water. Membrane processes such as NF or RO eliminate inorganic ions and reduce parameters like conductivity, alkalinity or salinity, etc. 

Thus, under ideal conditions, ERH is the % relative humidity of an atmosphere in which a foodstuff may be stored without a net loss or gain of moisture. Water activity, together with temperature and pH, is one of the most important parameters which determine the rates of chemical, biochemical and microbiological changes which occur in foods. However, since aw presupposes equilibrium conditions, its usefulness is limited to foods in which these conditions exist. 

Microbiological processes in soil water systems are very important because they often control or drive certain soil reactions. For example, one of the parameters that dictates the type and extent of many reactions in soils is pH. The latter, however, is often controlled by biological processes because they either produce or consume acid. The microbial reactions that produce acid include ... 

Growth models that describe the dependence of primary model parameters on environmental factors (i.e., temperature, water activity, pH, and organic acids) are referred to as secondary growth models. A number of different secondary model types exist in predictive microbiology and are discussed in the following section (Wilson et al., 2002). 

DEVLiEGHERE F, DEBEVERE J and VAN IMPE J (1998), Concentration of caibon dioxide in the water-phase as a parameter to model the effect of a modified atmosphere on microorganisms. International Journal of Food Microbiology, 43, 105-113. 

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