Bacteriocins are bacterially produced antimicrobial peptides with narrow or broad host ranges. Many bacteriocins are produced by food-grade lactic acid bacteria, a phenomenon which offers food scientists the possibility of directing or preventing the development of specific bacterial species in food. This can be particularly useful in preservation or food safety applications, but also has implications for the development of desirable flora in fermented food. In this sense, bacteriocins can be used to confer a rudimentary form of innate immunity to foodstuffs, helping processors extend their control over the food flora long after manufacture.

Bacteriocins: developing innate immunity for food

Yeasts are predominant in the ancient and complex process of winemaking. In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts, with the final stages invariably being dominated by the alcohol-tolerant strains of Saccharomyces cerevisiae. This species is universally known as the ‘wine yeast’ and is widely preferred for initiating wine fermentations. The primary role of wine yeast is to catalyze the rapid, complete and efficient conversion of grape sugars to ethanol, carbon dioxide and other minor, but important, metabolites without the development of off-flavours. However, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing quest for specialized wine yeast strains possessing a wide range of optimized, improved or novel oenological properties. This review highlights the wealth of untapped indigenous yeasts with oenological potential, the complexity of wine yeasts’ genetic features and the genetic techniques often used in strain development. The current status of genetically improved wine yeasts and potential targets for further strain development are outlined. In light of the limited knowledge of industrial wine yeasts’ complex genomes and the daunting challenges to comply with strict statutory regulations and consumer demands regarding the future use of genetically modified strains, this review cautions against unrealistic expectations over the short term. However, the staggering potential advantages of improved wine yeasts to both the winemaker and consumer in the third millennium are pointed out. Copyright # 2000 John Wiley & Sons, Ltd.

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Tailoring wine yeast for the new millennium: novel approaches to the ancient art of winemaking

Nisin was first introduced commercially as a food preservative in the UK approximately 30 years ago. First established use was as a preservative in processed cheese products and since then numerous other applications in foods and beverages have been identified. It is currently recognised as a safe food preservative in approximately 50 countries. The established uses of nisin as a preservative in processed cheese, various pasteurised dairy products, and canned vegetables will be briefly reviewed. More recent applications of nisin include its use as a preservative in high moisture, hot baked flour products (crumpets) and pasteurised liquid egg. Renewed interest is evident in the use of nisin in natural cheese production. Considerable research has been carried out on the antilisterial properties of nisin in foods and a number of applications have been proposed. Uses of nisin to control spoilage lactic acid bacteria have been identified in beer, wine, alcohol production and low pH foods such as salad dressings. Further developments of nisin are likely to include synergistic action of nisin with chelators and other bacteriocins, and its use as an adjunct in novel food processing technology such as higher pressure sterilisation and electroporation. Production of highly purified nisin preparations and enhancement by chelators has led to interest in the use of nisin for human ulcer therapy, and mastitis control in cattle.

Applications of the Bacteriocin, Nisin

http://wpage.unina.it/giamauri/Materiale_vario/Preservation_fermentation.pdf

Preservation and fermentation: past, present and future.

/pdf/biosynthesis-and-mode-of-action-of-lantibiotics-4ckj6jz79p.pdf

Biosynthesis and mode of action of lantibiotics.

In the normal course of the lactic fermentation the bacterial growth passes through four stages: the lag period, the period of rapid or logarithmic growth, the period in which there is little or no increase in numbers, and the final period in which fermentatior ceasesand the cells slowly die. Ti-a-dianges from the first to the second and from the second to tL... ird period are comparatively rapid and are accompanied by mo )hological and physiological changes in the cells. The transit n from the third to the fourth period is gradual. In the third period the cells may be in a quiescent condition ina which there is little or no multiplication, or the multiplication and death rate may be so nearly balanced that the number counted remains constant. Counts made by the plate method would be likely to give the impression that the latter is the case since only the living cells are counted. If direct microscopic counts are made and the population remains constant it must be assumed either that the --cells are quiescent or that they lose their ability to take stain very soon after death. In our work on this problem we used a microscopic count in order to avoid as far as possible the error introduced into the plate method by the tendency of the lactic streptococci to grow in pairs and chains. The very large numbers of cells with which it was necessary to work militated against accurate counts, and it was difficult to obtain a series of counts which would give a reasonably smooth curve. However, the constancy with which uniform counts were repeatedly secured under similar conditions indicated that 211

Limiting factors in the lactic fermentation

Lactose and its Utilization: A Review

The presented book we offer here is not kind of usual book. You know, reading now doesn't mean to handle the printed book in your hand. You can get the soft file of byproducts from milk in your gadget. Well, we mean that the book that we proffer is the soft file of the book. The content and all things are same. The difference is only the forms of the book, whereas, this condition will precisely be profitable.

Byproducts from milk

Ethyl Alcohol from Whey

It requires only a casual examination of the literature to show that there is much confusion in regard to the differentiation of the members of the lactobacillus group. While bacteriologists who have worked with this group may have quite definite concepts of the various species it is difficult to translate those concepts into concrete terms which define a biological species. This is especially true of the acidophilus cultures, since they have been selected more on the basis of their ability to grow under certain prescribed conditions than because of compliance with taxonomic criteria. Much of the confusion in bacteriological nomenclature is due to the use of a limited number of cultures in determining a basis for describing species and to reliance on characters which are inconstant and have little taxonomic significance. The natural grouping of bacteria is based on fundamental physiological characters which the members of these groups possess in common. Correlated with these are more superficial, and sometimes more obvious, characters which may permit an easy identification. In establishing a classification it is clear that the emphasis should be placed more on the stable basic characters and less on those which are superficial. The isolation of cultures for identification is more or less a matter of chance and, if only a few are studied, there is always a possibility that these are not representative of the species as it occurs in nature. We have used as many cultures as the laborious nature of many of the determinations would permit.

E.O. Whittier

Papers

Limiting factors in the lactic fermentation

Lactose and its Utilization: A Review

Byproducts from milk

Ethyl Alcohol from Whey

The Distinguishing Characteristics of Lactobacillus acidophilus