Background: The microbial evolution of the J’ben Elgafs prepared with raw milk from local cows, was studied during the manufacturing and maturating process in order to characterize this variety of cheese from the Algerian terroir.Methods: The microbial activity and physical-chemical parameters were tested during the three dairy seasons of the year. Total, lactics and alteration floras were counted on their selective environments.Result: Lactic germs multiply considerably during the first days and only stabilize towards the end of maturation. The low presence of alteration floras is the result of the continuous modification of the physico-chemical parameters of Aw and pH from one stage to the other of the j’ben production and the respect of good processing practices. These different proportions of variation are induced by the biochemical reactions and microbial interactions that take place responsible for the sequential growth of one microbial group compared to another.

Background: The purpose of the study is to evaluate the diversity of lactococci, lactic bacteria, recovered from “J’ben”, a local cheese made from the milk of the Rembi sheep breed, a product of exploitation in the Algerian steppe regions of Naama.Methods: The bacterial species were isolated from samples of the recovered cheese exploitation and analyzed using genotypic methods. The isolation of bacterial DNA from purified Lactococcus cultures has been established by an amplification of ribosomal DNA 16s using the specific universal primers of prokaryotes. Result: The 16s DNA sequencing of all isolates, for genotypic identification, confirmed the predominance of Lactococcus lactis. This lactic dominance determines the quality and distinctiveness of this cheese in the region. The results obtained from acidification and proteolysis kinetics met the technological requirements and good functionality, from the strains used individually and in mixed culture to the cheese processing.

Background: The cheese-making ability of milks varies due to its chemical composition and several factors related to good farming practices.Methods: Among these factors, the lactation stage was studied on a batch of 15 Prim’Holstein dairy cows under real production conditions at the experimental farm of the University of Mostaganem. The fresh milks produced were tested with simple criteria of chemical composition in protein rate, butyrous rate, mineral intake, on coagulation ability and cheese yield with a repeatability spread over 3 months. Result: The results indicated that the lactation stage has a significant effect, on the composition of milk, especially in terms of protein and mineral richness and on its ability to coagulate. In addition, the urea dosage showed a deficiency in the food ration of digestible nitrogen to the herd directly influenced the protein mass of milk and consequently on the technological processing times and cheese yields.

Background: Fresh raw milk is a highly nutritious but perishable product. Its informal sale without control, is detrimental to the health of the consumer. Therefore, assessing the hygienic and sanitary quality of raw milk is an absolute necessity. Methods: 20 raw milk samples from four regions of Mostaganem City, Algeria, were tested on a microbiological compliance aspect. A serologic analysis was carried out for the indirect detection of brucellosis and a questionnaire was developed to check the hygiene rules applied at the sales store level. Result: The results indicate an average high contamination of 8.109 cfu/ml for aerobic germs at 30°C versus 12.104 cfu/ml for thermotolerant coliforms. The presence of Staphylococcus with positive coagulase and anti-brucella antibodies indicates that these milks are potentially hazardous to human health. Salmonella is absent in all samples. The field investigation shows the proven absence of the most basic hygiene rules for the storageand presentation for sale of raw milk. A quality approach must be put in place at the service of the consumer.

Background: The increase of multidrug-resistant pathogens causes increased concerns about the efficacy of conventional treatment, which requires the search for new alternatives to antibiotics. The present study aimed to evaluate the antibacterial activity of lactobacilli isolated from eight (n=8) typical Apis mellifera honey produced in Mostaganem region against four pathogenic bacteria responsible of bovine mastitis. Methods: Lacbacilli strains, isolated from different media were firstly presumptively identified by catalase test, Gram staining and cells morphology, than confirmed by partial 16S rRNA sequence analysis. Antibacterial activity of isolates was determined by the overlay agar method. Antibiotic susceptibility of mastitis pathogens was tested by disk diffusion technique. Result: Two species of lactobacilli were isolated and identified as Lactobacillus plantarum and Lactobacillus pentosus. Antibiotic sensitivity test demonstrated that mastitis pathogens showed the resistance to antibiotics tested. All the isolates showed antimicrobial activity with inhibition zone diameters ranged from 5±0.02 to 21±2.12 mm. The results revealed that honey can be considered as a source of Lactobacillus with antibacterial activities which can be used as alternative treatment of bovine mastitis.

Background: Technological characterization of lactic acid bacteria isolated from sheep’s milk collected in 3 regions in northwestern Algeria.Methods: During the period from 2018 to 2019, fifty strains of Lactic acid bacteria isolated from samples sheep’s milk were evaluated for several technologically-relevant properties: diacetyl and exopolysaccharides production, acidification, proteolytic and lipolytic activity and their antagonist activity against Escherichia coli and Pseudomonas aeruginosa. Result: The results indicate that among all the isolates only 20% were distinguished by their production of EPS mainly the genus Leuconostoc. Diacetyl production was observed in 71% of Lactobacillus, 60% of Enterococcus and 25% in Leuconostoc. 94% isolates showed moderate proteolytic activity. 56% and 60% of the strains degraded tween 80 and olive oil respectively for lipolytic activity. Inhibition activity by the cultures LAB was about 82% and 78% against E. coli and P. aeruginosa respectively. No culture supernatants inhibit P. aeruginosa, however 18% of the Enterococcus trains inhibit E. coli. BME1.A2 and BME2.D4 showed their highest acidification capacity developing a very large quantity of lactic acid after 24 h of incubation, i.e., 7.6 and 8.4 g lactic acid/L respectively.

Background: The appreciation of microbial milk communities, in order to promote useful flora and inhibit pathogenic one, has become one of the key factors in controlling the quality of cheeses.Methods: In this context, an approach to assess the bacterial flora of raw cow’s milk, was tested in 05 wilayas in north-western Algeria, on the one hand by a preliminary count of total flora and a phenotypic characterization based on morphological criteria and on the other hand by a genotypic identification of selected isolates, by the PCR method and sequencing of the gene encoding for the 16S ARNr.Result: The results of molecular analysis obtained from 72 isolates allowed the identification of 12 bacterial species with a dominance of the lactic microflora, 37% Lactococcus and 29% Enterococcus. This milk-native lactic microflora has become the main vector that preserves the distinctiveness of dairy products, including local cheese.