The Microbiological Quality of Raw and Pasteurized Milk in Alexandria with Special Reference to the Incidence of some Cold-Tolerant Pathogens | ||||
| Journal of High Institute of Public Health | ||||
| Article 3, Volume 31, Issue 2, April 2001, Page 217-232 | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jhiph.2001.233505 | ||||
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| Authors | ||||
| Sawsan M.L. El-shishnagui1; Saleh S.K. T2; Fathalla M. G3 | ||||
| 1Department of Food Hygiene, Animal Health Research Institute, Agriculture Research Center, Alexandria, Egypt | ||||
| 2Department of Food Hygiene, Animal Health Research Institute, Agriculture Research Center, Cairo, Egypt | ||||
| 3Department of Microbiology, Central Laboratory of Food and Feed, Agriculture research Center, Alexandria, Egypt | ||||
| Abstract | ||||
| A total of 108 [60 raw and 48 pasteurized] milk samples were collected from dairy shops and supermarkets in Alexandria governorate, and examined for its microbiological load [total mesophilic, total psychrotrophic and total yeast and mold counts] as well as for the incidence of Aeromonas hydrophila (A. hydrophila], Listeria monocytogenes [1. monocytogenes and Yersinia enterocolitica [y. enterocolitica]. The samples were taken monthly for a period of one year, starting from December 1999 to November 2000. The obtained results rvealed that the total aerobic mesophilic count fall between 10° and 10° c.f.u/ ml in raw milk and between 10³ and <10 c.f.u/ ml in pasteurized milk. 15% of raw milk samples had counts <10°, 31.7% had counts of 10% <10 and the rest of samples had counts between 10-10 c.f.u/ ml..Most pasteurized milk samples [ 48.8 %) had aerobic mesophilic counts of 10 - <10%. respect of total psychrotophic counts, 5% of raw and 45.8% of pasteurized milk samples were negative. Most raw milk samples [63.3% ] fall between 10⁰ 10 and that of pasteurized milk fall between 105 - 10º. Total mould and yeast were found in all raw milk samples and most of such samples [51.7%] were between 10²-10³. However 39.9% of pasteurized milk samples were negative for total mould and yeast and most of positive samples [52.1%] fall between 10² - <10%. In raw milk samples, the mean total aerobic mesophilic, total psychrotrophic, total yeast and mould counts [c.f.u/ ml] were 7.4, 6.8 and 2.8 respectively. However the figures in pasteurized milk were 4.9, 3.8 and 1.4 respectively. The general incidence of the psychrotrophic pathogens in raw milk samples were 30%, 13.3% and 28.3% for hydrophila, L. monocytogenes and Y. enterocolitica respectively. The figures of pasteurized milk were 6.3%, 4.2% and 2.1% respectively. The peak of the incidence of A. hydrophila was during May to September months, while that of L. monocytogenes was during November and January and that of Y.enterocolitica was during July and August. The figures of pasteurized milk were 6.3%, 4.2% and 2.1% respectively. The peak of the incidence of A. hydrophila was during May to September [late spring and summer], while that of L. monocytogenes was during November and January [late autumn and winter]. Y.enterocolitica was during July and August [summer]. The serotyping of the isolated L. monocytogenes strains showed that 50% of raw and 100% of pasteurized milk isolates were belonged to serotype 01.and 37.5% of raw milk isolates were of serotype 04, while 12.5% were not confined to either of such serotypes. | ||||
| Keywords | ||||
| Microbiological Quality; Raw; Pasteurized; Milk; Alexandria; Incidence; Cold-Tolerant Pathogens | ||||
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