Microbiological stability

Stability considerations Chemical stability Physical stability Microbiological stability Bioavailability stability... 

Ultra-high-temperature treatment (UHT) is now the most widely exploited method in the food industry to stabilize microbiologically any foodstuff. It consists of heating at an ultra high-temperature for a short period of time for example, a treatment at 145°C for 2 seconds is sufficient to assure a total microbial- and spore inactivation. The microbial death is principally due to irreversible cell damage (e.g., of proteins, DNA, RNA, vitamins) enzymes are inactivated by heat which modifies their active sites. 

This is an issue which is yet to be properly analyzed. It could lead to a resurgence in bacteria levels, and it is important that it is not the opportunistic photogenic bacteria which lead that resurgence. In such a transient phase, water quality will also be unstable, and it would be inadvisable to utifize this water for the larvae. Ozone may also have effect on ions in the water making them unstable. Microbiological stabilization, microbiological water maturation or water ripening may therefore be a suitable water treatment for disinfected water or raw water, to help control the bacterial... 

When a pharmacist regularly produces a specific preparation for an individual patient, a better substantiation of the design quality is necessary. Both literature and experimental research may provide extra information about the pharmacotherapy and about pharmaceutical properties such as homogeneity, stability microbiological quality, compatibility, tolerability, and taste. For this, the pharmacist may use data from other pharmacies as well. Furthermore, more specific in-process controls may be added to the preparation process. An end control (usually non-destructive) by the operator is required for every batch, as well as a more specific validation of the preparation method. 

J. S. Swan, in G. Charalambous, ed.. Handbook of Food and Beverage Stability Chemical, Biochemical, Microbiological, and NutritionalMspects, Academic Press, Inc., Ltd., London, 1986, p. 801. 

In many patent orHterature descriptions, a stabilized chlorine dioxide solution or component is used or described. These stabilized chlorine dioxide solutions are in actuaHty a near neutral pH solution of sodium chlorite that may contain buffer salts or additives to obtain chlorite stabiHty in the pH 6—10 range. The uv spectra of these solutions is identical to that of sodium chlorite. These pH adjusted chlorite solutions can produce the active chlorine dioxide disinfectant from a number of possible organic or inorganic chemical and microbiological reactions that react, acidify, or catalyze the chlorite ion. 

It is well known that pine enzymes change then behaviour and stability when they are immobilised. In the past two decades the immobilisation of microorganisms, cells and parts of cells has gradually been introduced into microbiology and biotechnology. The cell immobilisation techniques are modifications of the techniques developed for enzymes. However, the larger size of microbes has influenced the techniques. As for immobilised enzymes, two broad types of method have been used to immobilise microorganisms attachment to a support and entrapment. 

Possible exposure to pesticide-derived N,-nitroso compounds depends on environmental processes that influence formation, movement, and degradation of the compounds. Although laboratory studies have shown the feasibility of environmental nitrosamine formation, there has been little evidence that it is an important process. Nitrosamines vary greatly in their environmental stabilities, but all seem to be susceptible to one or more modes of decomposition including photolysis, microbiological degradation, and plant metabolism. 

The number of samples of reference material needed is a commercial issue in the first place. An important variable is the number of samples likely to be sold during the lifetime ( shelf life ) of the reference material. As the lifetime is a function of the intrinsic stability of the material, this variable also affects the amount of raw material is needed. For instance, microbiological materials have limited intrinsic stability, and therefore their lifetime is expected to be shorter than for a dry sediment certified for trace elements. So, under the assumption of an equal number of sam-... 

Onset of side effects Urinary elimination Microbiological stability... 

Activities encompassed by the stability program include sample storage of either development or production batches (or both), data collection and storage/retrieval, physical, chemical, and microbiological testing, document preparation of regulatory... 

Meyer RS, Grant MA, Luedecke LO and Leung HK. 1989. Effects of pH and water activity on microbiological stability of salad dressing. J Food Prot 52 477-479. 

In bakery products the pH of the product is important for several reasons. Acid foods are normally relatively safe microbiologically as a low pH inhibits the growth of bacteria. Fruit flavoured products such as fruit pie fillings normally have some acid component added to complement the fruit flavour. Where a hydrocolloid is present the pH of the product can be critical in terms of product stability or gelling. A hydrocolloid held at its isoelectric point, i.e. the pH at which there is no net charge, will likely come out of solution. 

Greiff, D., Rightsel, W. A. Stabilities of dried suspensions of inflenza virus sealed in vacuum or under different gases. Applied Microbiology 17, Table 3, p. 830-835, 1969... 

Japanese workers 5 have described the stability of bulk fradiomycin (neomycin B)sulphate which was shown to have retained 99% of its microbiological potency after storage for 24 months. Neomycin sulphate powder has been reported to be stable for at least 3 years at 20°C 298,305 ... 

The two main assumptions underlying the derivation of Eq. (5) are (1) thermodynamic equilibrium and (2) conditions of constant temperature and pressure. These assumptions, especially assumption number 1, however, are often violated in food systems. Most foods are nonequilibrium systems. The complex nature of food systems (i.e., multicomponent and multiphase) lends itself readily to conditions of nonequilibrium. Many food systems, such as baked products, are not in equilibrium because they experience various physical, chemical, and microbiological changes over time. Other food products, such as butter (a water-in-oil emulsion) and mayonnaise (an oil-in-water emulsion), are produced as nonequilibrium systems, stabilized by the use of emulsifying agents. Some food products violate the assumption of equilibrium because they exhibit hysteresis (the final c/w value is dependent on the path taken, e.g., desorption or adsorption) or delayed crystallization (i.e., lactose crystallization in ice cream and powdered milk). In the case of hysteresis, the final c/w value should be independent of the path taken and should only be dependent on temperature, pressure, and composition (i.e.,... 

Titanium dioxide is a very stable compound with excellent stability towards light, oxidation, pH changes, and microbiological attack. It is virtually insoluble in all common solvents. It is available in oil-dispersible and water-dispersible forms with a wide variety of carriers. Titanium dioxide is a very effective whitener for confectionery, baked goods, cheeses, icings, toppings, and numerous pharmaceuticals and cosmetics. 

Microbiological stability implies that sterility or resistance to microbial growth is retained according to the specified requirements. Antimicrobial agents that are present will retain their effectiveness within specified limits. 

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