جستجوی مقالات مرتبط با کلیدواژه "biochemical tests" در نشریات گروه "صنایع غذایی"

Kimchi is a general term for fermented vegetables.The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product used biochemical and molecular methods. In this study, after successive culture on specific media, in order to classify of 85 selected isolates that according to preliminary experiments seemed Lactic Acid Bacteria, physiological and biochemical tests were done and then fermentation of 10 different carbohydrates were performed. Based on these tests, 85 isolates were divided into 10 groups. Some isolates were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in Kimichi was as followings: Lactobacillus plantarum (41.17%), Lactobacillus fermentum (9.41%), Enterococcus faecalis (3.52%), Enterococcus faecium (7.06%), Leuconostoc citreum (2.35%), Leuconostoc mesenteroides (3.52%), Pediococcus pentosaceus (8.23%), Wisella cibaria (24.70%). This fermented product has a wide microbial diversity which originates from natural microbiota presented in the raw vegetable. Lactic acid bacteria can produce a variety of acids and enzymes which play an important role in development of unique flavor and tasteTherefore, this strains that isolated from Kimchi can be used in the food industry.

One of the pathogenic bacteria species in the genus of Lactococcus is Lactococcus garvieae. It causes human disease (endocarditis) and mastitis in dairy cows to appear. The presence of these bacteria in the raw milk products like Lighvan cheese was reported. Lighvan cheese is a traditional cheese which is made from raw sheep's milk.In this study, fresh milk, curd, Fresh cheese and ripe cheese, and fresh grass Lighvan area was used to isolate bacteria. Biochemical tests at 10°C and 45°C and grow in salt concentration 4% and 6.5 %, was performed. After extraction of DNA, PCR reaction with primers for genes of Lactococcus 16S rRNA performed and the products were sequenced by the company Source BioScience England, then in gene databases NCBI, the sequence of which more than 97% were similar in terms of genus and species were identified.At first, 1500 colonies similar to Lactococcal genera isolated from different sources such as fresh grass, fresh milk, curd, fresh cheese and ripened cheese according to colony morphology. Then, the 625 isolates were selected by gram stain. The biochemical tests carried out to select 60 isolates of Lactococcal genus and the PCR was used to determine the 16S rRNA gene sequence region to identify species. Based on molecular identification 50 species, were belonged to the Lactococcal genera and finally two species of Lactococcus were Lactococcus garvieae.According to the results, the presence of two species of Lactococcus garvieae (fresh milk and curd) was demonstrated in the early stages of Lighvan cheese production, But, there was no presence of the bacteria in fresh cheese and ripened cheese.