Lactococcus lactis W8 produced nisin concomitantly while fermenting milk to ‘‘dahi’’, a traditional Indian fermented milk. The activity of nisin was detected at 3 h of fermentation, which increased in parallel to growth of the organism and reached its maximum at 6 h. The activity remained essentially stable thereafter. At 7 h of fermentation of milk with the strain L. lactis W8 the pH of the me...

Gram-negative Pseudomonas and Gram-positive Bacillus are the most common spoilage bacteria in raw and pasteurized milk, respectively. In previous studies, nitrogen (N2) gas flushing treatments of raw and pasteurized milk at cold chain-temperatures inhibited bacterial spoilage and highlighted different susceptibilities to the N2 treatment with the exclusion of certain bacterial types. Here, we i...

Clostridium sporogenes is a food contaminating anaerobic bacteria causes late bowing effect in cheeses and spoilages in other dairy products. A total of 150 samples were studied for the presence of Clostridium sporogenes in raw milk, curd and cheese samples. Out of 150 sample 11(22%) Clostridium sporogenes was found in raw milk, 7(14%) in curd and 2(4%) in cheese samples. The study shows the ex...

Changes in milk proteins effected by bacterial action are important in various aspects of the ripening of cheese and the proteolytic spoilage of dairy products in refrigerated storage. Paper electrophoresis has afforded a new method for the study of protein systems such as those in milk (MacRae and Baker, 1958; and Weigt, 1959), including the detection of certain changes occurring in such syste...

The wide array of available dairy foods challenges the microbiologist, engineer, and technologist to find the best ways to prevent the entry of microorganisms, destroy those that do get in along with their enzymes, and prevent the growth and activities of those that escape processing treatments. Troublesome spoilage microorganisms include aerobic psychrotrophic Gram-negative bacteria, yeasts, m...

The aim of this study was to optimise the antimicrobial efficacy of plant essential oils (EOs) for control of Listeria spp. and spoilage bacteria using food model media based on lettuce, meat and milk. The EOs evaluated were lemon balm, marjoram, oregano and thyme and their minimum inhibitory concentrations (MIC) were determined against Enterobacter spp., Listeria spp., Lactobacillus spp., and ...

A bacteriocin producing strain of Lactococcus lactis subsp. lactis LABW4 was isolated from naturally fermented milk product which exhibited strong antibacterial activity against Listeria monocytogenes MTCC657, a food spoilage psychrophilic organism. Both cell free and heat killed supernatants of LABW4 were effective to produce zones of inhibition against L. monocytogenes in vitro. The antibacte...

A psychrophilic strain of bacteria identified as Chromobacterium lividum was established as the causative agent of an outbreak of violet discoloration in refrigerated, pasteurized retail milk and cream. The organism was rod-shaped, gram-negative, and produced viscid colonies with abundant violet pigment on Tryptone glucose yeast extract agar. Growth was abundant at 4 C but none occurred at 37 C...