R. Praseeda and E. Nanuz

Journal of Veterinary and Animal Sciences.2007. 38:42-48.

Open Access

Copyright: © 2007 R . Praseeda This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.





An investigation on microbial qualify assessment of curd produced in a dairy plant was done by collecting 80 samples consisting of eight samples each of pooled raw buffalo milk, pasteurized milk, skim milk (SM), heat treated skim milk, starter culture, starter inoculated milk after 1 and 6 h of inoculation and fresh curd from 10 different batches of production. All the samples were subjected to estimation of total viable count (TVC), coliform count (CC), Escherichia coli count (FCC), psychrotrophic count (PC), faecal streptococcal count (FSC) and yeast and mould count (YMC). Highly significant (p<0.01) difference was noted between the TVC of skim milk and starter inoculated milk with that of fresh curd. Coliforms were present in raw, pasteurised and SM, but not in heat freated SM. Yeast and moulds were not detected in heat treated SM, but was observed in starter culture inoculated milk. Fresh curd samples had yeast and mould at the level of 103 cfu/g. The mean pH reduced from 6.8 ± 0.01 in heat treated SM fo 3.6 ± 0.01 in fresh curd. The TVC of starter culture was 6.4 ± 0.21 log10 cfu/g. Coliforms and faecal streptococci were not detected in the starter culture. The critical control points of microbial contamination of curd was identified and among the CCP assessed (viz., air, water, hand wash, package material and equipment wash) the mean TVC and CC was highest in the hand washings of personnel involved in processing. E. coli was detected only in hand washings at the level of 0.05 ± 0.05 logo cfu/ml. Faecal streptococci were defected bofh in hand washings and tap water samples. TVC was highest for cream separator and lowest for the packaging material. Faecal streptococci were detected in all the samples tested and highest count was observed in washings from storage can. Double jacketed vat had the highest coliform count. Air samples collected from the various areas of the production line after processing had high mean TVC and YMC.

Key words: Curd, microbial qualify, CCP