Characterization of Staphylococcus Species Isolated from Raw Milk and Milk Products (lben and jben) in North Morocco

Background: To investigate the incidence and antibiotic resistance of staphylococcal strains isolated from milk and milk products and to trace the ecological origin of the Staphylococcus aureus isolated. Methodology: Eighty-one samples of raw milk; lben (whey) and jben (cheese) were analyzed for the presence of staphylococcal strains. Isolates were identified by Gram stains; tests for coagulase; the API staph system and the WalkAwayr 40/96; which also determines the antimicrobial susceptibility profiles. The S. aureus strains were biotyped; and variable regions of the coagulase gene were amplified using the polymerase chain reaction. Results: The identification results showed a predominance of coagulase-negative staphylococci (54). Coagulase-positive staphylococci that were identified were divided into 3 groups comprising S. aureus (40); Staphylococcus intermedius (2) and Staphylococcus hyicus (4). Among the S. aureus that was isolated; biotype C was the predominant biotype. Among 40 coagulase gene PCR-amplification products; 37 produced a single band; while 3 isolates produced two bands. The antimicrobial susceptibility-profile of the staphylococcal strains revealed a high incidence of S. aureus to penicillin G. In addition; Staphylococcus lentus presented considerable resistance to the oxacillin; erythromycin and lincomycin. Conclusions: The presence of staphylococci in raw milk; lben and jben in areas of northern Morocco poses a health hazard; so it is necessary for the public health inspectors to properly examine the conditions during production; storage and commercialization of all products made with unpasteurized milk. Key Words: milk products; Staphylococcus; coagulase-gene typing; biotyping; antimicrobial susceptibility

Aspects of Microbial Quality of some Milk Products in Abuja Nigeria

Purpose: To assess the microbiological quality of some milk products in Abuja; Nigeria capital city; and the resistance of isolates to some broad spectrum antibiotics. Method: Three packs of different brands of yoghurt and pasteurized milk purchased from four different locations were assessed in duplicate. Isolates were identified using growth on agar and broth; Gram's reaction; colony morphology; biochemical tests results and criteria for disregarding negative cultures. Resistance of isolates from pasteurized milk was determined using the antibiotic sensitivity test (zones of inhibition). Results: 33 bacterial and 12 fungal isolates belonging to 9 and 3 genera respectively were identified from the yoghurt samples. Presence of yeast was found to increase the microbial load of bacteria groups and decrease the load of live and active cultures which was absent in 33of yoghurt samples. 27of samples were heat-treated and contained no LAC. A total of 19 bacterial isolates belonging to 6 genera were identified from the pasteurized milk samples. Milk quality based on methylene blue decolourization time measurement revealed that 49of the assessed samples were of excellent quality; 37of good quality; 14of fair quality; and 0of poor quality. No milk sample was sterile. Among the three antibiotics tested for resistance on the isolated bacterial strains; three different resistance patterns were observed. Conclusion: Our study shows that mesophilic yeast was the main cause of yoghurt spoilage. Sampled yoghurt is unlikely to make a vital input to LAC intake in Nigerian diets and poses some yet undefined risk. Visual inspection of packages; quality assessment of diary plants/vessels and packaging materials; dye reduction tests; refrigeration at all times; and resistance testing should be critically considered before the use of recommended antibiotics.of yoghurt samples. 27of samples were heat-treated and contained no LAC. A total of 19 bacterial isolates belonging to 6 genera were identified from the pasteurized milk samples. Milk quality based on methylene blue decolourization time measurement revealed that 49of the assessed samples were of excellent quality; 37of good quality; 14of fair quality; and 0of poor quality. No milk sample was sterile. Among the three antibiotics tested for resistance on the isolated bacterial strains; three different resistance patterns were observed. Conclusion: Our study shows that meso- philic yeast was the main cause of yoghurt spoilage. Sampled yoghurt is unlikely to make a vital input to LAC intake in Nigerian diets and poses some yet undefined risk. Visual inspection of packages; quality assessment of diary plants/vessels and packaging materials; dye reduction tests; refrigeration at all times; and resistance testing should be critically considered before the use of recommended antibiotics