Preparation of Starter Cultures

Before the availability of commercial cultures, wineries relied on native microflora to induce MLF. With the widespread use of wooden storage 

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Preparation of starter culture of E. coli 71/18/JM101/JM103... 

Estimating microbiological population density and diversity plays important and often pivotal roles at several junctures in the winemaking process. For instance, it is frequently necessary to determine changes in microbial populations during the preparation of starter cultures, growth and decline phases of malolactic fermentation, or monitoring potential Brettanomyces infections. 

Park and Marth (1972B) prepared a series of cultured milks which contained Salmonella typhimurium. Survival of salmonellae in the products stored at 11 °C ranged from less than three days to more than nine days, depending on species of starter culture, strain of a given species, level of inoculum used to prepare the cultured product, temperature at which the product was cultured, and amount and speed of acid production. In other studies, Park et al (1970) noted that S. typhimurium survived for up to seven to ten months in Cheddar cheese made with a slow acid-producing starter culture and stored at 13° or 7°C, respectively. In contrast, Goepfert et al. (1968) and Hargrove et al. (1969) found that S. typhimurium survived for three to seven months... 

Henick-Kling, T. (1995). Control of malo-lactic fermentation in wine Energetics, flavour modification and methods of starter culture preparation. J. Appl. Bacteriol. 79, 29S-37S. Imazio, S., Labra, M., Grassi, F., Scienza, A., and Failla, O. (2006). Chloroplast microsatellites to investigate the origin of grapevine. Genet. Resour. Crop Evol. 53,1003-1011. 

Henick-Kling, T. 1995. Control of malo-lactic fermentation in wine Energetics, flavour modification and methods of starter culture preparation. J. Appl. Bacterial Symp. Supp. 79, 29S-37S. 

Mugula, I., Narvhus, J., Sprhaug, T. (2(X)3). Use of starter cultures of lactic acid bacteria and yeasts in the preparation of togwa, a Tanzanian fermented food. International Journal of... 

The use of fermentation to preserve and improve the properties of food has a long history. For example, milk has been preserved by fermentation for at least seven millennia (Dunne et ah, 2012). Initially, fermentation was a spontaneous process, probably with mixed results, and it was quickly learned that inoculation of the material to be fermented with a suitable inoculum would increase the likelihood of success. Traditionally, this was done by using part of a previous fermentation as an inoculum, but as microbiological knowledge increased, inoculation with specifically prepared fermentation starter cultures developed (Hpier et al., 2010). This in turn gave a better control of the fermentation process and allowed for the development of new products with novel properties. This is well illustrated in the dairy industry, where a diversity of bacterial species is used to manufacture a large variety of fermented dairy products (Table 10.1). 

Kefir is also prepared from commercial starters using bovine milk and it has been reported that the lactose concentration effectively decreased from 4.92%(w/v) to 4.02%(w/v) and the L(+)- lactic acid concentration increased to 0.76%(w/v) from 0.01%(w/v) after 24 hours of incubation. The acetic acid content increased from 2.10 to 2.73 mg/ml while the pH value was reported to be low as 4.24 in the first 24 hours after which it decreased gradually. The concentration of L(+)- lactic acid subsequently decreased while that of D(-)- lactic acid subsequently increased. These fermentation values depend on the type of starter culture used, the storage period and the medium used to grow the kefir (for example the mammalian species from which the milk is derived, the coconut water, etc.), (Garcia Fontan, Martinez, Franco, Carballo, 2006 Magalhaes, Pereira, et al., 2011 Oner, Karahan, 0akmak9i, 2010). 

Starter cultures of L. oenos ML 34 for inoculating wine are obtained by inoculating the grape juice medium with 1 vol % of a subculture (or another starter culture). The subculture is prepared by inoculating 5 ml of the grape juice medium from a stab culture. The cultures are incubated at room temperature until turbidity is seen,... 

These approaches have been reviewed extensively (Jameson, 1990 Ardo, 1997 Fenelon and Guinee, 1997 Fenelon, 2000). Various recommendations for the manufacture of reduced-fat cheeses with improved sensory and textural properties (Mistry et al., 1996 Johnson et al., 1998), (e.g., half-fat Cheddar prepared by homogenization of cream used to standardize the cheese milk) (Nair et al., 2000) the combined effects of increases in milk pasteurization temperature and pH at curd milling, and the use of selected starters and starter culture adjuncts (Guinee et al., 1999 Fenelon et al., 2002) ... 

Both proteolysis and lipolysis are involved in the cheese ripening process. The rate and extent of their interactions are influenced by the rennet preparation used, characteristics of the starter culture, pH, moisture range, salting practices, temperature, and the activity of adventitious microorganisms present in or on the cheese. 

The effect of complex commercial fermentation activators on biogenic amine production was tested by Marques et al. (2008). On the whole, it does not seem that complex nutrient preparations produced for the use with fermentation starter cultures pose a serious threat to biogenic amine production in wines. 

Starter cultures are mainly applied as liquid cultures with about 10 to 10 ° microorganisms per ml. They are also available in a freeze-dried or deep frozen preparation with the advantage of very simple application. 

When the fermentation is at its height in the demijohn, which will be when the must still contains 3 or 4 per cent of sugar, it is ready to use to prepare a bulk starter. This is best prepared in a small open vat or tub, varying in size according to the amount of starter needed daily. Into this tub are poured twenty to fifty gallons of well-defecated must extracted from clean, sound grapes. It is not necessary to boil it, as the few micro-organisms it may contain will be without effect in the presence of the vastly more numerous yeast cells introduced from the pure culture in the demijohn. 

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