Physicochemical and Bacterial Properties of Pasteurized Milk Samples Collected from Tabriz, Northwestern Iran

Authors

1 Department of Food Hygiene and safety, School of Health, Qazvin University of Medical sciences, Qazvin, Iran

2 Asia-Pacific center for animal health, Faculty of veterinary and agricultural sciences, University of Melborn, Parkville, Victoria 3010, Australia

Abstract

Milk and dairy products are important components of a balanced diet. Milk does have distinct physicochemical, biological and microbial characteristics. The bacterial contamination of milk not only reduces the nutritional quality but its consumption threatens health of the society. In this study, 100 pasteurized milk samples were collected randomly from Tabriz City, northwestern and were analyzed for total plate count (TPC), coliform, E. coli and some physicochemical properties (pH, titratable acidity and density). 33.3% of samples had unacceptable microbial contamination in both warm and cold seasons. E. coli contamination was not detected in all milk samples, but 54% of pasteurized milk samples were contaminated with coliforms. The pH value (6.6-6.8) and titratable acidity (0.14-0.16%) were in acceptable range. The means value of samples’ density was 1028.79±1.04. Lower microbial contamination level in this area indicates that the dairy factories are concerned about appropriate sanitary practice and pasteurization process.

Keywords


  1. Farre R.R., 2015. Milk and milk products: food sources of calcium. Nutr Hosp. 31, 1-9.
  2. Spanu V., Spanu C., Virdis S., 2012. Virulence factors and genetic variability of Staphylococcus aureus strains isolated from raw sheep's milk cheese. Int J Food Microbiol. 153, 53-7.
  3. Vahedi M., Nasrolahei M., Sharif M., Mirabi A.M., 2013. Bacteriological study of raw and unexpired pasteurized cowââ‚‌™s milk collected at the dairy farms and super markets in Sari city in 2011. Prev Med Hyg. 54, 120-123.
  4. Damico D.J., Donnelly C.W., 2011. Characterization of Staphylococcus aureus strains isolated from raw milk utilized in small-scale artisan cheese production. J food Prot. 74(8), 1353-8.
  5. Rosengren A., Fabricius A., Guss B., Sylven S., Lindgvist R., 2010. Occurrence of food-borne pathogens and characterization of Staphylococcus aureus in cheese production on farm-dairies. Int J Food Microbiol. 144(2), 263-9
  6. Byamukama D., Mach R.L., Kansiime F., Manafi M., Farnleitner A.H., 2005. Discrimination efficacy of fecal pollution detection in different aquatic habitats of a high-altitude tropical country, using presumptive coliforms, Escherichia coli and Clostridium perfringens spores. Appl Environ Microbiol. 71, 65ââ‚‌“71.
  7. Scavia G., Escher M., Baldinelli F., Pecoraro C., Caprioli A., 2009. Consumption of unpasteurized milk as a risk factor for hemolytic uremic syndrome in Italian children. Clin Infect Dis. 48, 1637-1638.
  8. Omiccioli E., Amagliani G., Brandi G., Magnani M., 2009. A new platform for Real-Time PCR detection of Salmonella spp., Listeria monocytogenes and Escherichia coli O157 in milk. Food Microbiol.26, 615-622.
  9. Amagliani G., Petruzzelli A., Omiccioli E., Tonucci F., Magnani M., Brandi G., 2012. Microbiological surveillance of a bovine raw milk farm through multiplex real-time PCR. Foodborne Pathogens Dis. 9(5), 406-411.
  10. Gunasekera T.S., Sorensen A., Attfield P.V., Sorensen J., Veal D.A., 2002. Inducible gene expression by non-culturable bacteria in milk after pasteurization. Appl Environ Microbiol. 68(4), 1988-1993.
  11. Teshme G., Fekadu B., Mitiku E., 2015. Physical and chemical quality of raw cowââ‚‌™s milk produced and marketed in Shashemene Town, Southern Etiopia. J Food Agri Sci. 5(2), 7-13.
  12. Park J., Kim M., 2013. Comparison of Dry Medium culture Plates for Mesophilic Aerobic Bacteria in Milk, Ice Cream, Ham, and Codfish Fillet Products. Prevent Nutr Food Sci. 18(4), 269-272.
  13. Alexopoulos A., Tzatzimakis G., Bezirtzoglou E., Plessas S., Stavropoulou E., Sinapis E., Abas Z., 2011. Microbiological quality and related factors of sheep milk produced in farms of NE Greece. Anaerobe .17, 276-279.
  14. Almenida C., Sousa J.M., Rocha R., Cerqera L., Fanning S., Azevedo N.F., Vieira M.J., 2013. Detection of Escherichia coli O157 by Peotid Nucleic Acid Fluorescence In situ Hybridization (PNA-FISH) and Comparison to a standard Culture Method. Appl Environ Microbiol. 79(20), 6293-6300.
  15. Van Schaik G., Green L.E., Guzman D., Esparza H., Tadich N., 2004. Risk Factors for Bulk Milk Somatic Cell Counts and Total Bacterial Counts in Smallholder Dairy Farms in the 10th Region of Chile. Prevent Vet Med. 67, 1-17.
  16. Holm C., Mathiasen T., Jespersen L., 2004. A Flow Cytometric Technique for Quantification and Differentiation of Bacteria in Bulk Tank Milk. J Appl Microbiol. 97, 935-941.
  17. Giacometti F., Bonilauri P., Serraino A., Peli A., Amatiste S., Arrigoni N., 2013. Four-year monitoring of food-borne pathogens I raw milk sold by vending machines in Italy. J Food Prot. 76 (11), 1902-7.
  18. Jackson E.E., Erten E.S., Maddi N., Graham T.E., Larkin J.W., Blodqett R.J., Schlesser E., Reddy R.M., 2012. Detection and enumeration of four foodborne pathogens in raw commingled silo milk in the United States. J Food Prot. 75(8), 1382-93.
  19. Przysucha T., Grodzki H., Zdziarski K., 2003. The influence of delivery system monthly milk supply and season on TBC in raw milk qualified to the highest quality classes. E J Polish Agr Univ. 68,115-22.
  20. Schoder D., Maichin A., Lema B., Laffa J., 2013. Microbiological quality of milk in Tanzania: from Maasai stable to Africa consumer table. J Food Prot. 76(11), 1908-15.
  21. Tiqabu E., Asrat D., Kassa T., Sinmeqn T., Molla B., Gebreyes W., 2015. Assessment of Risk factors in milk Contamination with Staphylococcus aureus in Urban and Peri-Urban Small-Holder Dairy Farming in Central Ethiopia. Zoonoses Public Health. 2015.
  22. Mhone T.A. , Matope G., Saidi P.T., 2011. Aerobic bacterial, coliform, Escherichia coli and Staphylococcus aureus counts of raw and processed milk from selected smallholder dairy farms of Zimbabwe. Int J Food Microbiol. (151)2, 223-8.