Living microorganisms are widely used for several therapeutic purposes and their beneficial effects as biotherapeutic agents are well known. While certain strains of lactic acid bacteria and bifidobacteria are used as probiotics in pharmaceutical preparations, feed additives and so-called functional foods yeasts also possess some medicinal efficiency.

The use of high temperature short time heat treatment (HTST) of milk (72°C for 15 seconds) to destroy pathogenic bacteria, reduce the number of spoilage organisms and increase shelf life is well established (Juffs and Deeth, 2007).

The history of pasteurization (pasteurisation is also valid) is fascinating and is notable for its public health success and for the insights of many scientists and engineers. Prior to the introduction of pasteurization, consumption of raw cow milk was a major source of infection by bacteria causing tuberculosis. Pasteurization has eliminated heat-treated-milk as a source of infection. Regrettably raw milk and raw milk products remain a major source of new cases of bovine tuberculosis.

This article calculates the effect of HTST treatment on the number of log reductions of major milk pathogens and discusses the temperature milk should be pasteurized if Mycobacterium avium subsp. paratuberculosis (MAP) was designated as a human pathogen. The log reductions refer to log10 or decimal (10 fold) reductions in the concentration of viable bacteria. The article does not discuss the effects of heat on the functional properties or the nutritive quality of milk. An updated and reviewed version of this paper has been published (Mullan, 2019).

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Any agent which inhibits starter activity or kills a strain with an essential function e.g. aroma production can have serious detrimental effects on the quality of the product being produced. Infection with bacteriophage is the major single cause of fermentation failure or of problems in fermentation processes utilising lactic acid bacteria.

The major functions of starters in dairy fermentations are shown in table 1. See the section on starters also.

This article discusses the major functions of starters in dairy fermentations. Recent research on the relative importance of the antimicrobial agents produced by starters is included. The importance of undissociated lactic acid (HLac) is discussed with regard to the inhibition of the growth of Listeria monocytogenes, Escherichia coli and Staphylococcus aureus.

The author recommends that regulators should require manufacturers of raw milk cheeses to meet a minimum value for HLac that must be achieved prior to product release for retail sale.

Characteristics - Toma del Lait brusc is a typical Piedmont cheese with a cylindrical appearance and flat surfaces. The cylindrical shape has a diameter of 25-35 cm, an edge of 12-18 cm and a weight of 4-8 kg. Ripening lasts at least 60 days but frequently is longer e.g. 180 days. The crust is wrinkled, hard, and reddish-grey with yellow and white highlights. The dough is ivory-white or dark-yellow with small holes. Typical greenish-blue veins due to mould growth may be present in ripened cheese. The texture is consistent, compact and very friable. In young cheeses, the odour is fine and delicate, becoming very strong and persistent in aged products. The taste is mainly sweet and fine but savoury, salty and intense in aged products.

Production area - The cheese is produced in the high pastures throughout Turin province.

Peroxidases catalyse reactions in which hydrogen peroxide is reduced and a suitable electron donor is subsequently oxidised.  A wide variety of organic and inorganic substances can serve as electron donors, but substrate specificity varies between various peroxidases.

Most assays are based on the principle that the electron donor in oxidised form absorbs light and can be determined by a spectrophotometric assay.

"Pro" means "for" or "in favour of," "biotic" means "life." Thus, probiotic means "for/in favour of life." It contrast directly with "anti," "biotic" or "killing life." The Nobel Prize winning Russian scientist Elie Metchnikoff first conceptualised probiotics; defined as viable microorganisms that are beneficial to human health, at the turn of the 20th century. He believed that the fermenting bacillus (now called Lactobacillus bulgaricus) contained in the fermented milk products consumed by Bulgarian peasants positively influenced the micro flora of the colon, thus decreasing toxic microbial activities. Lilly and Stillwell probably first introduced the term “probiotics” in 1965, as growth promoting factors produced by microorganisms. However, the term ‘probiotic’ was popularised by R. Fuller in 1989 and defined as a live microbial feed supplement, which beneficially affects the host by improving its intestinal microbial balance. This definition was later extended to include other beneficial effects such as immunomodulation. There is a popular view that probiotics are the "medicine" of the twenty first century. The World Health Organization (FAO/WHO, 2002) has defined probiotics as live microorganisms, which when administered in adequate amounts confer a health benefit.


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