PCR BASED DETECTION OF GRAM NEGATIVE PSYCHROTROPHIC BACTERIA IN COWS RAW MILK

A. Alrazakkazal, Amjed; A. Abdullah, Fawziah

doi:10.33762/bvetr.2016.124263

	PCR BASED DETECTION OF GRAM NEGATIVE PSYCHROTROPHIC BACTERIA IN COWS RAW MILK
Basrah Journal of Veterinary Research
Article 14, Volume 15, Issue 1, 2016, Pages 161-180 PDF (0 K)
DOI: 10.33762/bvetr.2016.124263
Authors
Amjed A. Alrazakkazal; Fawziah A. Abdullah
Abstract
Investigations of the proteolytic Gram Negative Psychrotrophs(GNP) bacteria was the basal objective of this study. A conventional diagnostic PCR technique based on three pairs of primers including SerAgeneto amplify an 950 bp fragment of Acinetobacter sppDNA,serAgene for/A. hydrophila ( 650bp): and aprgene for/S. marcescens (500bps) was done.In the present study the 29 bacterial isolates obtained from 100 cows raw milk samples were collected randomly from healthy cows with different age and breed present in different farms of Thi-Qar province, previously refrigerated for 72 hr. These isolates subjected to cultural-based enrichment and PCR- based identification .The present results revealed that the raw milk GNP contamination overall ratio was 29% . Acinetobacter spp were the most predominant bacteria (16%) among the studied GNP contaminants, while A.hydrophila appeared in a ratio of 7% and S. marcescens showed the lower ratio ( 6%). ,the results of the studied genes product of GNP bacteria was considered to be highly statistically significant (P>0.001).The distribution of studied GNP according to age ,parturition number and breed of studied animals was investigated. The effect of these factors on the PCR-based identification results was considered to be not statistically significant(P>0.05) however, the higher overall ratio(29.1%) for cow raw milk contamination was observed in raw milk of cows between <3 - < 9 year of age. In general cows at first age group (<3 - < 9 year) showed high ratio of raw milk contamination(7.6 and6.3%) with GNP bacteria (Serratia marscense and Aremonase hydrophila respectively)..Concerning the number of parturition, cows with high numbers of parturition( ˃ 6-<12) showed high overall ratio(38.5%) of contamination also high ratio of Acinetobacter spp(23.1%) ,Aremonase hydrophila(7.7%) and Serratia marscense (7.7%) were observed in the same group of cows. According to breed, a high overall ratio of GNP bacterial contamination was observed in 40% of crossbred cow raw milk followed by Friesian cows(32.1%).Beside that raw milk of crossbred cows showed a high ratio of contamination with Acinetobacter spp (20%) and Aremonase hydrophila(13.3%) while Serratia marscense appeared as a higher contaminant in Friesian cows raw milk with the ratio of its contamination was10.7%.
Keywords
raw milk; Gram negative; GNP

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