The growth and interaction of yeasts and lactic acid bacteria isolated from Zimbabwean naturally fermented milk in UHT milk

Gadaga, T.H.; Mutukumira, Anthony N.; Narvhus, Judith

doi:10.1016/s0168-1605(01)00466-4

Cited by 103 publications

(82 citation statements)

References 17 publications

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“…The validity of osmolality as an index of fermentation was confirmed by simultaneous measurements of pH and osmolality during spontaneous fermentation of UHT milk. Results obtained for changes in pH in the present investigation were in consonant with previous studies on spontaneous fermentation of UHT milk (Gadaga et al 2001). A negative correlation was found between pH and hypo-osmotic 8% normal 88%…”

Section: Discussionsupporting

confidence: 92%

Application of osmometry in quality analysis of milk

Musara

Pote

2013

J Food Sci Technol

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The aim of this study was to evaluate osmometry as a tool in quality analysis of milk. The osmolality of raw milk, sterilized milk, skimmed UHT (ultra-high temperaturetreated) milk, pasteurized milk, standardized UHT milk and fermented milk (Lactococcus lactis culture) was determined by freezing point osmometry. The relationship between osmolality and pH of fermented milk was further investigated during spontaneous fermentation of UHT milk at 37°C for 48 h. Average osmolality values (mean ± SD) were raw milk-290.2 ± 7.98, sterilized milk-290.2 ± 5.84, skimmed UHT milk-290.8±3.31, pasteurized milk-283.6±2.28, standardized UHT milk-281 ± 4.59 and fermented milk-466.0 ± 17.30 mOsmoles kg −1. For fresh milk samples, 88 % showed normal osmolality, 8 % were hypo-osmotic and 4 % hyper-osmotic. Fermentation studies revealed a high negative correlation between osmolality and pH, with a correlation coefficient of −97.49 %. Hypo-osmotic milk shows mixing of milk with water along the production chain. Hyper-osmotic milk indicates fermentation of milk at high ambient temperatures or with prolonged storage. It may also reveal adulteration of fresh milk with a soluble substance. Osmolality was highest for fermented milk owing to production of lactic acid during fermentation. This was confirmed by the high negative correlation between osmolality and pH of milk in fermentation studies. Hence the osmolality of fermented milks may be used as an index of the extent of fermentation.

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Section: Discussionsupporting

confidence: 92%

Application of osmometry in quality analysis of milk

Musara

Pote

2013

J Food Sci Technol

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“…delbrueckii subsp. bulgaricus.Lactobacillus usually predominated in the traditional naturally-fermented milk Gadaga et al, 2001;Isono et al, 1994;Kamber, 2008;Naersong et al, 1996;Uchida et al, 2007). In this study, Lactobacillus was also considered as dominant LAB strains, which accounted for 35.1% of the total isolates.…”

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confidence: 68%

Identification and characterization of the dominant lactic acid bacteria from kurut: The naturally fermented yak milk in Qinghai, China

Sun

Liu

Wei

et al. 2010

J. Gen. Appl. Microbiol.

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Forty-three samples of kurut, a kind of traditional naturally-fermented yak milk, were collected in Qinghai, China. One hundred and forty-eight lactic acid bacterial (LAB) strains were isolated and identifi ed from the kurut samples according to phenotypic characterization and 16S rRNA gene sequence analysis. Among them, 52 isolates belonged to the Lactobacillus strains. Ninety-six isolates were resolved to coccoid LAB. The results showed that these isolates belonged to fi ve genera and thirteen different species and subspecies. Moreover, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were the predominant population in these samples. This paper systematically studied the composition of LAB in kurut, which may provide raw data for further study involving probiotics strain selection and starter culture design for industrialization production of traditional fermented milk in the future. lactic acid bacteria (LAB). The presence of fermentative LAB is crucial to the intrinsic properties of fermented dairy products (Ehrmann et al., 2002;Tamine and Robinson, 1988). LAB have a long history of safe use, especially in the dairy industry. They play a major role in the production of fermented food, such as the key fl avor, texture and preservative qualities (Ahmad and Irene, 2007;Atrih et al., 2001;Messens and Vuyst, 2002). Recently, some of them have been completely sequenced (Altermann et al., 2005;Guchte et al., 2006;Pridmore et al., 2004). Therefore, comparative genomic analysis can help us to understand the genetic and biological diversity in LAB (Makarova and Koonin, 2007;Makarova et al., 2006;Morita et al., 2008). Key Words-identifiAs yet, information on microbiological composition of kurut is scant. Thus, it is necessary to select LAB strains with benefi cial function and stabile fermentation properties from the traditional fermented milk products, and then use them to design the starter cultures for commercial production. Based on this point, this study was undertaken to enumerate, isolate, identify and characterize the dominant microorganisms from kurut samples obtained from Qinghai, using the conventional method and 16S rRNA sequence analyses. Materials and MethodsSample collection. A total of 43 samples of kurut were collected from scattered households in Qinghai Province of China with temperature ranging from 10.8 C to 39.3 C. At each location, approximately 500 ml kurut were taken aseptically into sterile glass bottles after through mixing in the bulk kurut container. The pH values of these samples were determined at the sampling site using a calibrated portable pH-meter (pH100, Extech, USA). The kurut was collected within 15 min at ambient temperatures, and kept on ice during a 2 h transport. The operation for collection of all kurut samples was completed within 48 h. The microbiological analysis was carried out immediately after the samples arrived at the laboratory.Reference Enumeration of microorganisms. The 10 1 dilution was made by diluting 1 ml of kurut within 9 ml of physiol...

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“…Concerning the minor LAB found in koumiss samples, L. acidophilus, L. delbrueckii, and L. kefi ranofaciens, have been frequently reported in various dairy products Gadaga et al, 2001;Isono et al, 1994;Khedid et al, 2009;Naersong et al, 1996;Uchida et al, 2007). Strains of this group were most relevant to texture properties of the fermented milk for production of acid, folic acid, and exopolysaccharide, and synthesis of vitamins during growth (Forssen et al, 2000).…”

Section: Primermentioning

confidence: 96%