ABSTRACT
Aims: To evaluate the effectiveness of low pressure carbon dioxide as a hurdle in raw milk storage. Study Design: Milk samples were stored at under low pressure carbon dioxide at 29°C for 6 hours and the microbial quality of milk was compared with control milk. Place and Duration of Study: Department of Dairy Microbiology, Verghese Kurien Institute of Dairy and Food Technology (VKIDFT), Kerala Veterinary and Animal Sciences University, Mannuthy between January 2020 and December 2020. Methodology: Milk samples were collected from an organized farm. The initial microbial quality of milk was determined and samples were carbonated to a pressure of 20 psi and stored for six hours 29°C, uncarbonated milk sample kept at 29°C acted as the control. The microbial quality of the carbonated milk and uncarbonated milk was determined after storage in terms of total viable count, coliform count and gram negative organism count. Results: Significant growth suppression (P=0.05) of bacteria was observed in the carbonated milk. Total Viable count showed a suppression of 1.05 log cfu/ml while coliforms showed a suppression of 1.3 log cfu/ml. The greatest log reduction was observed in gram negative organisms with a difference of 2.2 log cfu/ml and psychrotrophic organisms with 1.54 log cfu/ml. Conclusion: Carbon dioxide was found to be an effective bacteriostatic agent which could be used for extending the keeping quality of raw milk. The bacteriostatic action could be due to anaerobic conditions developed by carbon dioxide and also due to the increased acidity of the medium.
ABSTRACT
Aims: To determine the prevalence of Candida species in ‘thairu’, a traditional fermented milk prepared in the households of Kerala. Study Design: ‘Thairu’ samples collected randomly from the households in Wayanad, Kozhikode, Malappuram, Palakkad and Kannur districts of Kerala. This was followed by enumeration and identification of yeast using API 20CAUX Kit. Determination of pH and acidity of samples. Place and Duration of Study: Department of Dairy Microbiology, College of Dairy Science and Technology, Pookode, Wayanad, Kerala. September 2021- December 2021. Methodology: A total of 30 household ‘thairu’ samples were collected from households of Wayanad, Kozhikode, Malappuram, Palakkad and Kannur districts of Kerala in sterile bottles. The samples were serially diluted in normal saline and pour plated on to Yeast Extract Glucose Chloramphenicol Agar for isolation and enumeration. The pH was measured using pH meter by directly inserting the probe into the homogenized sample. Titratable acidity in per cent lactic acid was measured using N/10 NaOH. The isolates were identified based on the sugar fermentation pattern using API 20C AUX kit (Biomerieux, France). Results: The yeast count in the samples ranged from 5.0 to 6.7 log CFU/g with an average of 5.89±0.38 log CFU/g. Average acidity and pH of the samples were 1.92±0.34 % LA and 3.59±0.60 respectively. A total of 23 yeast isolates were identified based on morphology and carbohydrate fermentation pattern using API 20C AUX kit (Biomerieux, France). Exactly 86.95 per cent of isolates belong to Candida species. Conclusion: Observations of the study revealed the high prevalence of Candida species in traditional fermented milk ‘thairu’. Predominant Candida species were lactose fermenters, but the presence of a few species with spoilage and pathogenicity potential were also detected. The safety assessment of Candida species is essential before applying them as starter cultures for food fermentations.
ABSTRACT
Aims: To identify predominant microorganisms in dish washing scrubbers collected from ten different sources. Study Design: Collection of dish wash scrubbers from different sources, pour plating of appropriately prepared dish wash scrub suspensions and subsequent isolation and identification of predominant isolates. Assessment of antibiotic susceptibility of the selected isolates by disc diffusion assay. Place and Duration of Study: April, 2018 - June 2018. Methodology: A total of 10 dish wash scrubbers (synthetic green scrubber pads free from any anti-bacterial preservatives belonging to the same brand) were collected from various sources. Appropriately prepared dish wash scrub suspensions in peptone water were pour plated on Plate Count Agar (PCA) and MacConkey agar. Predominant colonies selected from the plates based on the colony morphology were subjected to Grams staining, catalase, oxidase, indole, citrate, urease tests and genotypic identification by 16S ribosomal RNA sequencing. The identified isolates were tested for their susceptibility to eight antibiotics by disc diffusion method. Results: Irrespective of the sample source, most of the dish wash scrubbers sampled harbored similar types of colonies. From the colonies obtained two of them were identified by 16S rRNA sequencing and subsequent blasting as Klebsiella pneumoniae and Acinetobacter radioresistens. The isolates were deposited in the NCBI database with accession numbers MK032217 (Klebsiella pneumoniae RSV02) and MK032134 (Acinetobacter radioresistens RSV 01). These isolates were tested for their susceptibility to different antibiotics and Acinetobacter radioresistens RSV 01 was found to be more antibiotic susceptible than Klebsiella pneumoniae RSV02. Conclusion: Observations of this study confirm the potential role of dish wash scrubbers as vehicle for potential pathogens and their ability to act as cross contaminating agents in food processing environments.