Etude comparative du comportement de Streptococcus lactis, Streptococcus thermophilus et Lactobacillus bulgaricus dans des laits et des rétentats pasteurisés après stockage à l'état cru à basse température

Colostrum inoculated with Streptococcus lactis (treatment A), mixture of Streptococcus thermophilus and Lactobacillus bulgaricus (treatment B), Lactobacillus acidophilus (treatment C), naturally fermented (treatment D) and kept fresh (treatment E) was used in laboratory storage trial and without treatment E in calf feeding trial. Both trials were aimed at better control of the fermentation process of colostrum and improving its acceptability and nutritive value as the main feed for calves up to weaning. The fermentation, as indicated by pH and titratable acidity changes, was most effectively controlled by an early inoculation with S. lactis, although it had no effect on mold and yeast contamination. The use of this culture produced better (P < 0.05) overall daily gains (582.0 and 434.0 g for treatments A and D, respectively), higher (P < 0.05) daily consumption of starter feed (1131 and 893 g for treatments A and D, respectively) and lowest incidence of watery diarrhea in the calf feeding trial. In the laboratory storage trial, it resulted in highest (P < 0.05) levels of residual lactose in the fermented product (3.41, 1.61, 1.63 and 3.15% for treatments A, B, C and D, respectively). Early development of high acidity (below pH 4) in colostrum treated by a mixed culture of L. bulgaricus and S. thermophilus or by L. acidophilus led to premature termination of both trial treatments due to total refusal of colostrum by calves. However, both products were free of mold and yeast contamination for the duration of 25-day storage. To assure high palatability of colostrum and minimize acid sensitive contamination, it appears that fermentation should quickly lower and then maintain the pH within 4–4.5.

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SURVIVAL OF SALMONELLA TYPHIMURIUM IN REFRIGERATED CULTURED MILKS1

Journal of Milk and Food Technology ◽

10.4315/0022-2747-35.8.489 ◽

1972 ◽

Vol 35 (8) ◽

pp. 489-495 ◽

Cited By ~ 12

Author(s):

H. s. Park ◽

E. H. Marth

Keyword(s):

Lactic Acid ◽

Citric Acid ◽

Lactic Acid Bacteria ◽

Salmonella Typhimurium ◽

Streptococcus Thermophilus ◽

Lactobacillus Helveticus ◽

Lactobacillus Bulgaricus ◽

Refrigerated Storage ◽

Streptococcus Lactis ◽

Pure Cultures

Cultured skimmilks containing Salmonella typhimurium were prepared at 21, 30, or 42 C using different species of lactic acid bacteria (0.25, 1.0, and 5% inoculum) either singly or in combinations. Several commercial cultures also were used. Cultured skimmilks were stored at 11 C and tested at 3-day intervals for numbers of viable salmonellae and lactic acid bacteria and for pH. Survival of S. typhimurium varied from 6 to 9 days and from 3 to 6 days in milks cultured with 0.25% Streptococcus lactis at 21 and 30 C, respectively. Increasing the inoculum to 1% with incubation at 30 C yielded a product no more detrimental to S. typhimurium than when the lower inoculum was used at 30 C. Survival of S. typhimurium always exceeded 9 days when S. cremoris was used to make cultured skimmilks. Products made with commercial mixed cultures composed of S. lactis and S. cremoris allowed S. typhimurium to survive for periods intermediate between the extremes observed when pure cultures were used. Skimmilks cultured with Streptococcus diacetilactis and Leuconostoc citrovorum, even when skimmilks cultured with the latter organism were acidified with citric acid and incubated further, were essentially without effect on survival of S. typhimurium during refrigerated storage. Use of Streptococcus thermophilus (1% culture, 42 C incubation) yielded cultured skimmilks that were most detrimental to survival of salmonellae, whereas skimmilks fermented with Lactobacillus bulgaricus permitted survival of low numbers of salmonellae beyond 9 days. Milks cultured at 42 C with a 5% inoculum of S. thermophilus mixed with L. bulgaricus or Lactobacillus helveticus were free of viable salmonellae before the incubation was complete. Salmonellae grown in skimmilk at 21 C without a lactic culture were more resistant to inactivation during refrigerated storage than was S. typhimurium grown at 30 or 42 C.

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BEHAVIOR OF SALMONELLA TYPHIMURIUM IN SKIMMILK DURING FERMENTATION BY LACTIC ACID BACTERIA1

Journal of Milk and Food Technology ◽

10.4315/0022-2747-35.8.482 ◽

1972 ◽

Vol 35 (8) ◽

pp. 482-488 ◽

Cited By ~ 27

Author(s):

H. S. Park ◽

E. H. Marth

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Salmonella Typhimurium ◽

Streptococcus Thermophilus ◽

Mixed Cultures ◽

Lactobacillus Bulgaricus ◽

Complete Inactivation ◽

Streptococcus Lactis ◽

Streptococcus Cremoris ◽

Incubation Temperatures

Skimmilk was inoculated with Salmonella typltimurium (approximately 103/ml) and with Streptococcus cremoris, Streptococcus lactis, mixtures of S. cremoris and S. lactis, Streptococcus diacetilactis, Streptococcus thermophilus, Lactobacillus bulgaricus, mixtures of S. thermophilus and L. bulgaricus, a mixture of L. helveticus and S. thermophilus, and Leuconostoc citrovorum. Inocula of lactic acid bacteria ranged from 0.25 to 5.0% and incubation temperatures from 21 to 42 C. Streptococcus cremoris, S. lactis, and mixtures of the two repressed growth but did not inactivate S. typhimurium during 18 hr of incubation at 21 or 30 C when the lactic inoculum was 0.25%. An increase in inoculum to 1% resulted in inactivation of S. typhimurium at 30 C by some of the mixed cultures. Both S. diacetilactis and L. citrovorum were less inhibitory to S. typhimurium than were S. cremoris or S. lactis. When added at the 1% level, Streptococcus thermophilus was more detrimental to S. typhimurium at 42 C than was L. bulgaricus. Mixtures of these two lactic acid bacteria, when added at levels of 1.0 and 5.0%, caused virtually complete inactivation of S. typhimurium during the interval between 8 and 18 hr of incubation at 42 C.

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Preservation of Lactic Acid Bacteria on Anhydrous Silica Gel for Three Years

Journal of Food Protection ◽

10.4315/0362-028x-46.8.699 ◽

1983 ◽

Vol 46 (8) ◽

pp. 699-701 ◽

Cited By ~ 3

Author(s):

MARIA C. T. DE SILVA ◽

MARIA A. TESSI ◽

MARIA A. MOGUILEVSKY

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Silica Gel ◽

Streptococcus Thermophilus ◽

Lactobacillus Helveticus ◽

Lactobacillus Bulgaricus ◽

Preservation Methods ◽

Streptococcus Lactis ◽

Streptococcus Cremoris ◽

Negative Effect

This study, which covers three years of storage. analyzes the application of silica gel preservation methods to lactic acid bacteria widely used in yogurt and cheese fermentation. Strains of Streptococcus lactis, Streptococcus lactis subsp. diacetylactis, Streptococcus cremoris, Streptococcus thermophilus. Lactobacillus bulgaricus, Lactobacillus helveticus and a yogurt culture were adsorbed on anhydrous silica gel in screw-cap tubes or in ordinary test tubes which were subsequently flame-sealed under vacuum. During 3 years. the bacteria were tested for viability by incubation in sterile milk. All of the bacteria retained their acidifying activity, with the exception of the yogurt culture. Extending preservation for more than 2 years had a negative effect on the activity of the yogurt culture. Results obtained support the use of screw-cap tubes which, in general, were suitable to preserve suspensions of lactic acid bacteria adsorbed on anhydrous silica gel.

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Lactic Acid Production in Milk Containing Cleaning or Sanitizing Compounds

Journal of Food Protection ◽

10.4315/0362-028x-47.3.197 ◽

1984 ◽

Vol 47 (3) ◽

pp. 197-199 ◽

Cited By ~ 2

Author(s):

MICHAEL B. LIEWEN ◽

ELMER H. MARTH

Keyword(s):

Lactic Acid ◽

Ammonium Chloride ◽

Acid Production ◽

Lactic Acid Production ◽

Streptococcus Thermophilus ◽

Lactobacillus Bulgaricus ◽

Titratable Acid ◽

Streptococcus Lactis ◽

Streptococcus Cremoris ◽

Dry Milk

Sterile reconstituted nonfat dry milk containing 0.1% (v/v) each of 19 cleaning or sanitizing compounds intended for use on dairy farms or in milk factories was inoculated with Streptococcus lactis 4175, Streptococcus cremoris C-13, Streptococcus thermophilus ST4 or Lactobacillus bulgaricus. Milk then was incubated at 32°C for 12 h and pH and titratable acid were determined. Five products (alkaline inflation cleaner, hypochlorite sanitizer-farm use, isopropanol udder wash, ammonium chloride detergent-factory use, alkaline cleaner A-factory use) were inhibitory to at least three of the four lactic acid bacteria at the 0.1% concentration. These were then tested at 0.050, 0.025, 0.012 and 0.006% concentrations. Of the five products, only the isopropanol udder wash (at all four concentrations) inhibited S. lactis and S. cremoris. The isopropanol udder wash at all four concentrations and the ammonium chloride cleaner at 0.050% inhibited L. bulgaricus. S. thermophilus was inhibited by the isopropanol udder wash at 0.050%, whereas the alkaline cleaner A-factory use, at 0.050 and 0.025%, may have been mildly stimulatory to acid production by this bacterium.

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