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19992
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Subject: Veterinary Public Health × End date: 1999 × Start date: 1999 × Type: Thesis × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    Bovine brucellosis in relation to public health
    (Department of Veterinary Public Health, College of Veterinary and Animal Sciences, Mannuthy, 1999) Vinod, V K; KAU; Nanu, E
    A serological survey was undertaken to assess the extent of brucellosis in bovines and humans. Serum samples from 1233 bovines and 747 human were collected. These samples were screened by Rose Bengal Plate Test (RBPT) and Standard Tube Agglutination Test (STAT). The samples which showed a positive reaction, either by RBPT or STAT or both were subjected to Heat inactivation test (HIT), 2- Mercaptoethanol test (MET) and EDTA agglutination test (EAT). Of the 610 slaughtered male bovine serum samples screened, 41 (6.72 per cent) was found positive by RBPT and 37 (6.07 per cent) by STAT. HIT, MET and EAT detected positive reaction in 32 (5.25 per cent), 26 (4.26 per cent) and 27 (4.43 per cent) samples respectively. A total of 23 samples were positive by all the above tests. Among the 518 slaughtered female bovine serum samples, RBPT detected 41 (7.92 per cent) samples as positive while only 38 (7.34 per cent) samples were found positive by STAT. HIT, MET and EAT detected positive reaction in 31 (5.98 per cent), 26 (5.02 per cent) and 28 (5.4 per cent) samples respectively. Twenty four serum samples were found positive for the disease by all the above tests. None of the serological test employed could detect a statistically significant difference in the seroprevalence of disease between males and females. Of the serum samples collected from 105 farm fed cows, six (5.7 per cent) samples were found positive for brucellosis by both RBPT and STAT. The number of samples found positive by HIT, MET and EAT were three (2.86 per cent), one (0.95 per cent) and two (1.9 per cent) respectively. Only one sample revealed a positive reaction for the disease by all the above serological tests. Among the 406 human male serum samples collected, six (1.47 per cent) revealed an agglutination reaction positive for the disease by RBPT while only four. (0.99 per cent) showed an agglutination titre positive for the disease by STAT. HIT, MET and EAT detected three (0.74 per cent) samples each as positive for the disease. Three samples revealed a positive reaction in all the above serological tests. Of the 327 human female serum samples screened, RBPT and STAT recorded a positive reaction in five (1.53 per cent) and four (1.22 per cent) samples, respectively. Three samples (0.92 per cent) each were found positive by HIT, and MET and EAT. Only three samples were found positive for all the serological tests used in this study. It was observed that serological tests employed in this study could not detect a statistically significant difference in the seroprevalence of disease between males and females. None of the serum samples collected from veterinary surgeons (10), animal attendants (two), and slaughter house workers (two) were positive for the disease. Of the serological tests employed in this study, RBPT detected the highest number of samples as positive followed by STAT, HIT, EAT and MET. It was also observed that, of the RBPT and STAT positive cases, HIT recorded maximum number of positive cases followed by EAT and MET. The reason for difference observed in the agglutination titre of the serum samples by the above tests were discussed.
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    ThesisItemOpen Access
    Bacterial profile of pasteurized milk and its public health significance
    (Department of Veterinary Public Health,College of Veterinary and Animal Sciences, Mannuthy, 1999) Reenu, John; KAU; Nanu, E
    A total of 100 pasteurized milk samples consisting of 20 each from five different brands namely A, B, C, D and E were subjected to different bacterial counts to evaluate the bacterial quality of milk samples available in and around Trichur. An attempt was also made to isolate and identify E. coli and to test the sensitivity of these isolates to six antibacterial agents. Brand D had the lowest total viable count (4.47 ± 4.23 10glO cfu/ml) and the highest was in C (7.65 ± 7.22 10glO cfu/ml)., Analysis of the data revealed a highly significant (p<0.01) difference in the count of the samples between brands except between A and E and B and C. The psychrotrophic count was lowest in samples belonging to brand D (3.57±3.23 10glO cfulml and highest in C (6.95± 6.73 10glO cfulml). Highly significant (p<0.01) difference in the count was noticed between samples belonging to all brands, except Band C. (. The lowest coliform count was observed in brand D (1.24 ± 1.0410glO cfulml) and highest in C (5.38 ± 5.13 10glO cfulml). Highly significant (p<0.01) difference was observed between the counts of samples belonging to different brands except between A and E and B and C. Samples of brand D were found to be free from E. coli. The highest E. coli count was found in brand B (3.39 ± 2.74 10glO cfu/ml) and lowest in C (0.87 ± 0.87 10glO cfulml). Highly significant (p observed between brands except between D and C, e and E and E and A. Of the hundred pasteurized milk samples examined, 82% did not meet the total viable count criteria prescribed by BIS (1992). Only 75% samples from brand D and 15% from E met the criteria. Eighty five per cent samples from brand D met the coliform count limit prescribed for pasteurized milk by BIS (1992). The per cent of samples belonging to brands E and A that met the above criteria was 35 and 25, respectively. Only five per cent samples from brands Band e met this en teria. Sixty four isolates were identified as E. coli . Antibiogram of these isolates . showed that 96.9% were sensitive to gentamicin and norfloxacin. The per cent of isolates that showed sensitivity to tetracycline, cotrimazine, cephotaxime and nitrofurantoin were 92.2, 67.2, 56.3 and 54.7 respectively. To study the effect of pasteurization on the bacterial quality of raw milk and to find out the shelf life under refrigerated conditions, one raw milk sample and 12 sachets of pasteurized milk were collected from a batch on each day from the dairy plant. This was repeated at varied interval for ten days. The total viable, psychrotrophic, coliform and E. coli counts of raw milk samples were 6.74 ± 6.17, 6.67 ± 6.13, 3.41 ± 2.93 and 2.42 ± 2.27 10glO cfu/ml. No E. coli was found in freshly pasteurized milk samples. Total viable count of these samples was 5.05 ± 4.38 10glO cfu/rnl. The psychrotrophic and coliform counts were 4.85 ± 4.26 10glO cfu/ml and 2.36 ± 2.01 10glO cfu/ml respectively. Pasteurization reduced total viable and psychrotrophic count by 2 log and the coliform count by one. In the refrigerated sample the initial bacterial growth rate was very slow, and there was no significant increase in total viable and psychrotrophic counts for up to seven days of storage. Thereafter the increase in these counts were significantly different from that of initial count. An increase in coliform count was observed but it did not differ significantly from that of freshly pasteurized milk. Off odour was detected for the first time on the io" day and it was noticed in 30% of the samples and by 11 th day 100% samples showed off odour. Only on 1 ih ( days clot on boiling was noticed for the first time, that too only in one sample from a '. batch. As far as pasteurized milk is concerned, clot on boiling is not a suitable test for assessing the quality of pasteurized milk. The storage life was found to be at least . nine days for pasteurized milk kept in a refrigerator. Inspite of the fact that bacterial counts were well above the suggested norms by BIS, the milk had a keeping quality of nine days. Hence there is an indication for modification of the existing norms.