The Combined Effect of Fortification of Media with Peptone and Control of Acidity on the Growth of Lactic Acid Bacteria | ||
| Journal of Food and Dairy Sciences | ||
| Article 5, Volume 9, Issue 3, March 2018, Pages 121-126 PDF (425.92 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jfds.2018.35427 | ||
| Authors | ||
| Dalia Kamel; Dina Osman* ; Nanis Gomah; A. Hassan | ||
| Department of Dairy Science, Faculty of Agriculture, Assiut University. | ||
| Abstract | ||
| The present work was carried out to investigate the combined effect of fortification of media with 1% peptone under control of culture acidity on the growth rate of Lactococcus lactis subsplactis , Lactococcus lactis subsp cremoris and Lactobacillus casei in sterilized skim milk incubated at 34°C. The obtained results indicated that:Lactococcus lactis subsp lactis grow in sterilized skim milk resulted in coagulation of milk after 12th hour of incubation, and was reached plate count of 28x106 CFU/ml.When the same strain grown in sterilized milk supplemented with 1% peptone under control of culture acidity no coagulation was observed up to the end of incubation period after 28th hour at 34°C, and it reached a plate count of 70x106 CFU/ml at the end of the exponential phase after 12th hour of incubation Cessation of growth in the culture started the stationary phase after 24th hour of incubation. The effect of added 1% peptone to sterilized skim milk under control of culture acidity on the colony forming units of Lactococcus lactis subsp cremoris, indicated that control sample grown in sterilized skim milk reached count of 55x106 CFU/ml after 12th hour of incubation. The corresponding values for Lactococcus lactis subsp cremoris grow with medium supplementation and control of culture acidity reached a plate count of 20x107 CFU/ml after 24th hour of incubation.When Lactobacillus casei grow in sterilized skim milk incubated at 34°C with medium supplementation with 1% peptone under control of culture acidity, the population density was several times higher in culture supplemented with peptone under control of culture acidity reached a population density of 17x107 CFU/ml, while only 23x106 CFU/ml were recorded by the same strain being grown as a control after 24th hour of incubation. | ||
| Keywords | ||
| lactic acid bacteria; titratable acidity; colony count; culture acidity control; Mrs Media | ||
|
Statistics Article View: 194 PDF Download: 469 |
||
