Stability, bacteriological

Desirability of Malo-Lactic Fermentation. Three important aspects of malo-lactic fermentation must be considered in appraising its desirability deacidification, bacteriological stability, and increased flavor complexity (4). 

Bacteriological Stability. The bacteriological stability provided by malo-lactic fermentation is its most important attribute. Wines aged before bottling (and which are susceptible to the fermentation) will nearly always be fermented during the first or second year. With proper post-fermentation treatment, these wines can be safely bottled without fear of further bacterial attack. We have seen no instances where a second bacterial fermentation has occurred once the malo-lactic fermentation was completed unless additions had been made to the wines or they had been blended. 

The bacteriological stability of guar gum dispersions may be improved by the addition of a mixture of 0.15% methylpar-aben and 0.02% propylparaben as a preservative. In food applications, benzoic acid, citric acid, sodium benzoate, or sorbic acid may be used. 

It is more resistant to shear, heat, bacterial, enzyme, and UV degradation than most gums Prolonged heating degrades viscosity. Bacteriological stability can be improved by the addition of mixture of 0.15% methyl paraben or 0.1% benzoic acid Stable in solution over a pH range of 1.0-10.5... 

The hop alpha acids as such occur in beer in concentrations up to 4 mg.l They do not have a bitter taste, even in amounts up to 100 mg.r (58,59). On the other hand, the hop alpha acids improve the foam stability (60), suppress the gushing of beer (61) and contribute to its bacteriological stability (62). The positive properties of the hop alpha acids, however, are much less prominent compared to those of the hop iso-alpha acids (see 5.5.). 

Maximum suppressors. Gelatin is widely used as a maximum suppressor in spite of the fact that its aqueous solution deteriorates fairly rapidly, and must therefore be prepared afresh every few days as needed. Usually a 0.2 per cent stock solution is prepared as follows. Allow 0.2 g of pure powdered gelatin (the grade sold for bacteriological work is very satisfactory) to stand in 100 mL of boiled-out distilled water for about 30 minutes with occasional swirling warm the flask containing the mixture to about 70 °C on a water bath for about 15 minutes or until all the solid has dissolved. The solution must not be boiled or heated with a free flame. Stopper the flask firmly. This solution does not usually keep for more than about 48 hours. Its stability may be increased to a few days by adding a few drops of sulphur-free toluene or a small crystal of thymol, but the addition is rarely worth while and is not recommended. 

LANFILGAS An integrated process for dealing with municipal waste which stabilizes the solid residue and generates methane by bacteriological innoculation. Developed by the Institute of Gas Technology, Chicago. 

The various enzyme products are marketed on the basis of activity. Sometimes the activity is determined by a standard enzyme assay, but more frequently the activity is determined by methods based upon the industrial application of the enzyme. Large consumers with well-equipped laboratories find it expedient to purchase concentrates, but smaller plants prefer to purchase enzymes at standardized activities. Materials compatible with the intended application are added to the enzyme products by the enzyme manufacturer to adjust the activity to the required value. Stabilizers, activators and other materials to improve the response of the enzyme are also added. In the case of enzymes for food applications, the usual bacteriological tests (e.g. absence of Salmonella, gas formers, etc.) are applied to the products. 

There is no evidence that the Neuse River toxin has yet been experimented with by the military, probably due to the toxin and bacteriological ban treaty. However, four dinoflagellate toxins were a part of the U.S. inventory in the not-so-far-distant past. Natural poisons were experimented with as far back as World War I. Crystalline ricin is confirmed at two World War I university sites and concerns us because of its purported stability and the ability to refine large quantities. By some accounts, it may be two orders of magnitude deadlier than sarin or as deadly as VX or soman. Ricin was the agent in the British M bomb developed for World War II. 

Some stabilizers are aimed at very specific uses such as antistatic agents (eliminating static electricity) and stabilizers active against bacteriological attack. Currently there are also additives for controled degradation of the polymer after the product has been used. 

It is important to note that in these studies of vitamin E supplementation, it is the stability of oxymyoglobin that is improved. There does not appear to be any effect of vitamin E supplementation on the absolute concentration of myoglobin. In addition, consumers often associate discolored meat with a high microbial load. While meat color is not necessarily an adequate indicator of bacteriological quality (Faustman et al., 1990), Arnold et al. (1992a) have shown that bacterial growth on meat from vitamin E supplemented cattle is similar to that of meat from control animals. Thus, while the color stability of vitamin E supplemented beef may be improved, microbial growth is unaffected. The question of whether such enhanced color stability masks a natural deteriorative process must be addressed and requires further research. 

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