INDUSTRIAL AND SAFETY CHARACTERIZATION OF Lactococcus garvieae ISOLATED FROM TRADITIONAL EGYPTIAN DAIRY PRODUCTS | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 3, Volume 5, Issue 7, July 2014, Page 491-499 PDF (467.03 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2014.53019 | ||||
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| Author | ||||
| W. M. El-Sharoud* | ||||
| Food Safety and Microbial Physiology Laboratory, Dairy Department, Faculty of Agriculture, Mansoura University | ||||
| Abstract | ||||
| A total of 90 samples of traditional Egyptian dairy products including 25 samples of each of Kariesh cheese, Domiati cheese, and Ras cheese and 15 samples of Laban Rayeb were collected and exmained for the presence of Lactococcus garvieae. Potential isolates were identified using physiological and PCR examinations. PCR analysis confirmed 66 out of 84 physiologically identified Lc. garvieae isolates. This indicated the importance of employing a relevant PCR assay to confirm the belonging of isolates to Lc. garvieae rather than relying only on phsiological tests. Lc. garvieae was found to be associated with all the examined products at incidence rates ranging from 20% to 32%. Lc. garvieae isolates recovered from these products were found to be able to develop acidity to levels that caused milk coagulation after 24 h. Acidity levels ranged from 0.52% to 0.78% (T.A.%). Lc. garvieae isolates also showed proteolytic activities ranging from 0.00 to 0.04 mg tyrosine/ mL. Isolates from Domiati and Ras cheese generally showed higher proteolytic activities than those associated with Kariesh cheese and Laban Rayeb. None of the examined isolates were able to express a lipolytic activity. All isolates were sensitive to vancomycin, whereas 3%, and 9% of them showed resistance to kanamycin and tetracycline, respectively. A limited number of the Lc. garvieae isolates (7.6%) could produce the biogenic amine tyramine, but all isolates were unable to produce histamine. These results suggest a potential role of Lc. garvieae in the processing and ripening of dairy products, but also highlight the necessity of applying safety assessments before any potential industrial use of its strains. | ||||
| Keywords | ||||
| Lactococcus garvieae; cheese; Traditional dairy products; proteolytic activity; Antibiotic resistance; biogenic amines; PCR | ||||
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