Preservatives evaluation

Potential chemical preservatives may be evaluated in the first place by the methods outlined above, especially by determining MIC values (section 3.6) or by viable counts (section 3.2). TheRW, CM andKS tests (sections 3.1.1 and 3.1.2) have no relevance in preservative evaluation. It will be recalled (section 2.5) that formula ingredients may reduce the efficiency of a preservative which has shown up well in conventional tests using culture media as the suspending fluid. 

Akers M.J. Taylor C.J. (1990) Official methods of preservative evaluation and testing. In Guide to Microbiological Control in Pharmaceuticals (eds S.R Denyer R.M. Baird), pp. 292-303. Chichester Ellis Horwood. 

Preservative evaluation standards include European Standard, EN 275 (1992), or American Wood Preservers Association standard, E5-00. (AWPA, 2002). 

A similar approximation should be applied to the components of the equation of motion and the significant terms (with respect to ) consistent with the expanded constitutive equation identified. This analy.sis shows that only FI and A appear in the zero-order terms and hence should be evaluated up to the second order. Furthermore, all of the remaining terms in Equation (5.29), except for S, appear only in second-order terms of the approximate equations of motion and only their leading zero-order terms need to be evaluated to preserve the consistency of the governing equations. The term E, which only appears in the higlier-order terms of the expanded equations of motion, can be evaluated approximately using only the viscous terms. Therefore the final set of the extra stress components used in conjunction with the components of the equation of motion are... 

The effectiveness of antioxidants as preservatives for fats and oils is evaluated by determining the rate of peroxide development using the Active Oxygen Method (AOM) (29). The development of a rancid odor is used to evaluate the stabiUty of food items (Schaal Oven StabiUty test) (30). 

Hounslow etal. (1988), Hounslow (1990a), Hostomsky and Jones (1991), Lister etal. (1995), Hill and Ng (1995) and Kumar and Ramkrishna (1996a,b) present numerical discretization schemes for solution of the population balance and compute correction factors in order to preserve total mass and number whilst Wojcik and Jones (1998a) evaluated various methods. 

The temperature of the system is proportional to the average kinetic energy (eq. (16.12), and therefore determines which parts of the energy surface the particles can exploit. Owing to the finite precision by which the atomic forces are evaluated, and the finite time step used, the total energy in practice is not constant (preservation of the energy to within a given threshold may be used to define the maximum permissible time step). 

Methods are described for determining the extent to which original natural color is preserved in processing and subsequent storage of foods. Color differences may be evaluated indirectly in terms of some physical characteristic of the sample or extracted fraction thereof that is largely responsible for the color characteristics. For evaluation more directly in terms of what the observer actually sees, color differences are measured by reflectance spectrophotometry and photoelectric colorimetry and expressed as differences in psychophysical indexes such as luminous reflectance and chromaticity. The reflectance spectro-photometric method provides time-constant records in research investigation on foods, while photoelectric colorimeters and reflectometers may prove useful in industrial color applications. Psychophysical notation may be converted by standard methods to the colorimetrically more descriptive terms of Munsell hue, value, and chroma. Here color charts are useful for a direct evaluation of results. 

The United States Pharmacopeia (1995, 23rd edn) also gives proeedures for evaluating the effieacy of antimierobial preservatives in pharmaceutieal produets. 

Reybrouck G. (1992) The evaluation of the antimicrobial activity of disinfectants. In Principles and Practice of Disinfection, Preservation and Sterilization (eds A.D. Russell, W.B. Hugo G.A.J. Ayliffe), 2nd edn, pp. 114-133. Oxford Blackwell Scientific Publications. 

Evrendilek, G. A., Dantzer, W. R., Streaker, C. B., Ratanatriwong, P., and Zhang, Q. H. (2001). Shelf-life evaluations of liquid foods treated by pilot plant pulsed electric field system. J. Food Process. Preserv. 25, 283-297. 

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