Heating 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. 

Storage tank and in the circulation loop at ambient temperature most of the time (this requires an extra heat exchanger with cooling water on the shell side). To achieve microbial control, such system (or any system that includes ambient loop) needs to be periodically sanitized by heating up its contents to about 80° C and holding the temperature for at least 1 hr. The sanitization frequency can vary from once a day to once a week or less the lower the frequency is, the more attention to the studies proving the effectiveness of the microbial control shall be expected. 

Justifications for the use of nonstandard (i.e., nonpreferred or nonpharmacopeial) methods of sterilization may include the heat instability of the active ingredient or an essential excipient. The choice of a method based on filtration through a microbial retentive filter and/or aseptic assembly should be justified, and the appropriate in process controls (including bioburden controls on active ingredients, excipients, bulk solutions, process time constraints etc) discussed in detail in the application. Commercial considerations should not form part of the argument for the application of a nonstandard sterilization process. The highest possible sterility assurance level should be achieved. 

Each bag or container of raw materials should be identified with a unique code, lot, or receipt number. This code should be used in recording the disposition of each lot. Raw materials will be held under quarantine until they are sampled, tested, and released. Raw materials should be carefully handled and stored to avoid any contamination or cross contamination. When bagged and boxed raw materials need to be stored, it must be done so in adequately cleaned buildings that are free of infestation by rodents, birds, insects, and other vermin, and the building should be maintained. A controlled environment may be necessary to avoid microbial contamination or degradation caused due to exposure to heat, air, or light. When the raw materials are stored outdoors, the containers should be adequate for the outdoor storage. 

Validation studies conducted on dry-heat sterilizers can be divided into two basic components. One component envelops all the physical elements that must be qualified, such as temperature control, air particulate levels, and belt speeds. The other component is the biological constituent, which involves studies that prove that the process destroys both microbial and pyrogenic contaminants. 

Heat flux calorimeters are bioreactors equipped with special temperature control tools. They provide a sensitivity which is approximately two orders of magnitude better than that of microcalorimeters, e.g. [33,258]. The evaluation and description of microbial heat release is based on a heat balance heat yields and the heat of combustion of biological components are central parameters for quantification [70]. Measurements obtained so far have been used to investigate growth, biomass yield, maintenance energy, the role of the reduction degree of substrates, oxygen uptake [414] and product formation [272]. 

At the completion of the cleaning process, the items should be free of contaminating residues including traces of prior products, free of endotoxin, and well-controlled in terms of total particulate and microbial levels. This level of control would be appropriate regardless of whether the items, equipment, or components are to be sterilized or not. Sterilization, other than by relatively high temperature dry heat, has only a modest impact on endotoxin levels cleaning provides the only means to control endotoxin for materials and equipment that is sterilized by other means. 

When reporting on dry-heat test data, relative humidity is measured and controlled instead of water activity. This is because of the fact that biological materials more closely parallel vapor pressure than water content, and vapor pressure of the gas atmosphere surrounding dry microbial cells is more easily measured and controlled than the water content inside the cell. ... 

Albumin solution, human (PhEur 2005) Human albumin solution is an aqueous solution of protein obtained from plasma. Separation of the albumin is carried out under controlled conditions so that the final product contains not less than 95% albumin. Human albumin solution is prepared as a concentrated solution containing 150-250 g/L of total protein or as an isotonic solution containing 35-50 g/L of total protein. A suitable stabilizer against the effects of heat such as sodium caprylate (sodium octanoate) or N-acetyltryptophan or a combination of these two at a suitable concentration, may be added, but no antimicrobial preservative is added at any stage during preparation. The solution is passed through a bac-teria-retentive filter and distributed aseptically into sterile containers, which are then closed so as to prevent contamination. The solution in its final container is heated to 60 1.0°C and maintained at this temperature for not less than 10 hours. The containers are then incubated at 30-32°C for not less than 14 days or at 20-25°C for not less than 4 weeks and examined visually for evidence of microbial contamination. 

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