3 microbiological changes

Gandy. Chocolate is subject to flavor or microbiological change. Inclusions such as nuts and fillings such as caramel are susceptible to water gain or loss. Chocolates, which are stable, are packaged in greaseproof papers and moisture/fat barriers such as polypropylene film (see Chocolate and cocoa). 

Haffajee AD, Uzel NG, Arguello El, Torresyap G, Guerrero DM, Socransky SS Clinical and microbiological changes associated with the use of combined antimicrobial therapies to treat refractory periodontitis. J Clin Periodontol 2004 31 869-877. 

Yusof N, Ahmad Ramli RA and Ali F. 2007. Chemical, sensory and microbiological changes of gamma irradiated coconut cream powder. Radiat Phys Chem 76(11—12) 1882—1884. 

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.,... 

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. 

Water activity of foods is an important thermodynamic property affecting stability with respect to physical, chemical and microbiological changes. Water activity, av, is the ratio of the vapor pressure of water in a system, (Pl)sy, to the vapor pressure of pure water, (Pv)w, at the same temperature. It is equal to the equilibrium relative humidity (ERH) established in the surrounding air. Thus ... 

Pruthi, J.S. and Misra, B.D. (1 963) Physico-chemical and microbiological changes in curry powders during drying, milling and mixing operations. Spices Bulletin 3(3-5), 8. 

The deposition amount of nitrate ion is shown in Fig. 4a. The amount was high at Tokyo and Osaka, which are the highly populated and industrialized areas with heavy traffic. The values of nitrate in the summer season, however, should be treated with much care, because some microbiological change of nitrate to ammonium ions may have occurred during the sampling period of one month (5). It is of interest to mention, however, that the annual deposition amounts of nitrate at the stations on the Japan Sea side were fairly constant around the value of 1.3 g/nry which is comparable to the amount reported by EML for the polluted area of the east coast of the United States (6). 

A summary of any significant manufacturing or microbiological changes made during the past year... 

Fuller ME and Manning JF, Microbiological changes during bioremediation of explo-sives-contaminated soils in laboratory and pilot-scale bioslurry reactors, Biores. Technol., 91, 123, 2004. 

The temperature at which food is held can have a great influence on the kind, rate, and amount of microbiological changes that would take place. The growth and metabolic reactions of microorganisms depend on enzymes the rates of enzyme reactions are directly affected by temperature. Destruction of microorganisms at high temperature is supposed to be caused by denaturation of proteins or nucleic acid and loss of cytoplasmic membrane function (Perry and Staley, 1997). 

This chapter comprehensively reviews the effect of high-pressure processing on various physicochemical and microbiological changes of foods. High-pressure processing could maintain food-quality attributes such as color, flavor, and nutritional values due to its limited effect on covalent bonds. However, under pressure. 

Greene, J.M. and WS. Caldwell Chemical and microbiological changes during flue-curing of NK-149 tobacco. 48th Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 48, Paper No. 29, 1994, pp. 40-41, see www.rjrtdocs.com 514931655 -1675 521118168 -8168. 

The chemical and microbiological changes that take place in activated sludge are not fully understood. In the microbial population heterotrophic bacteria dominate and these, with the saprobic protozoa, constitute the basic trophic level. Holozoic protozoa feeding on bacteria are also present. Fungi are present in low numbers, but algae axe usually absent. 

FIG. 5. Diagrammatic representations of the influence of water activity upon some chemical, enzymatic, and microbiological changes and on overall stability and moisture sorption properties of food products. Source Rockland and Nishi (1980). 

The packaging of polypropylene due to low gas permeability and light is appropriate and economical for a short time to market for packaging fruit jams (up to 150 days), maintaining acceptable products in terms of sensory and microbiological changes. 

Green umbu (Spondias Tuberosa Arr. Cam.) preserve physical, chemical and microbiological changes during storage. Journal of Food Processing and Preservation, Vol. 31, No. 2, pp. 201-210, ISSN 01458892... 

Biotechnological products in which water is a solvent, a medium for microbiological changes, and not a structural element of biopolymers... 

Delgado-Pando, G., S. Cofrades, C. Ruiz-Capillas, M. T. Solas, M. Triki, and F. Jimenez-Colmenero. 2011. Low-fat frankfurters formulated with a healthier lipid combination as functional ingredient Microstructure, lipid oxidation, nitrite content, microbiological changes and biogenic amine formation. Meat Set. 89 65-71. 

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