Characterization of lactic acid bacteria isolated from Algerian arid zone raw goats\' milk

Diversity and density of lactic acid bacteria isolated from Algerian raw goats\' milk in arid zones were studied by determination of morphological, cultural, physiological and biochemical characteristics. 206 lactic acid bacterial strains were isolated, with 115 of them belonging to lactic acid cocci and others to the genus, Lactobacillus. The representative species of the total cocci were Lactococcus sp. (76.16%), Streptococcus thermophilus (14.78%) and Leuconostoc sp. (8.6%). The dominating species is Lactococcus lactis subsp. Lactis. Lactobacilli species found in local raw goats\' milk and their proportion were: Lb. curvatus (25.25%), Lb. helviticus (10.98%), Lb. plantarum (9.89%), Lb. reuteri (9.89%), Lb. casei (7.69%), Lb. brevis (5.49%), Lb. bulgaricus (5.49%) Lb. paracasei (4.39%) and Lb. acidophilus (2.19%). Key Words: Lactic acid bacteria, raw milk, goat, arid zones, identification. African Journal of Biotechnology Vol.3(6) 2004: 339-34

Variability of aggressiveness and virulence of Erwinia carotovora subsp. carotovorum causing the soft rot on potato tubers in the western of Algeria

Soft rot symptoms were observed on potato plants in several potato cultivars in the western part of Algeria. A total of four strains of Erwinia are devided as follow: i) three strains of bacteria isolated from diseased tissues and soil, identified as Erwinia carotovora subsp carotovorum using conventional bacteriological and biochemical methods; and ii) one strain as Erwinia sp, not pathogens. In vitro tests, on tuber slices were set up to determine slices weight lost, which allows to find differences in cultivar susceptibility and isolate aggressiveness. Among the five cultivars, Laura was the most susceptible than the others tested cultivars. Moreover, it was found that MAI isolate was the most virulent than the other bacterial isolates. The results of this study should allow an optimization of the potato storage, after considering the susceptibility of a given cultivar to soft rot development and the aggressiveness

Characterization of lactic acid bacteria isolated from Algerian arid zone raw goats' milk

Diversity and density of lactic acid bacteria isolated from Algerian raw goats' milk in arid zones were studied by determination of morphological, cultural, physiological and biochemical characteristics. 206 lactic acid bacterial strains were isolated, with 115 of them belonging to lactic acid cocci and others to the genus, Lactobacillus . The representative species of the total cocci were Lactococcus sp. (76.16%), Streptococcus thermophilus (14.78%) and Leuconostoc sp. (8.6%). The dominating species is Lactococcus lactis subsp. Lactis . Lactobacilli species found in local raw goats' milk and their proportion were: Lb. curvatus (25.25%), Lb. helviticus (10.98%), Lb. plantarum (9.89%), Lb. reuteri (9.89%), Lb. casei (7.69%), Lb. brevis (5.49%), Lb. bulgaricus (5.49%) Lb. paracasei (4.39%) and Lb. acidophilus (2.19%)

ORIGINAL ARTICLE Evaluation of microbiological and sanitary quality of ewe's raw milk in Western of Algeria and detection of antibiotic residue by Delvotest Evaluation of microbiological and sanitary quality of ewe's raw milk in Western of Algeria and det

ABSTRACT In this study, a total of 105 ewe's raw milk of Ouled-Djellal breed were collected from three farms (Oran, Relizane and Mascara) in western of Algeria. They were analyzed for microbiological and physico-chemical characteristics. The pH, titriable acidity, temperatures and detection of antibiotics using the Delvotest were determined. For the study, a questionnaire was filled to collect information about herd sheep characteristics. Microbiological examination involved the estimation of total mesophilic aerobic flora (FAMT), total and fecal coliforms, Enterobacteriacea, fecal Streptococcus, Staphylococcus spp., Sulphite Reducing Clostridia (SRC), Salmonella, Yeast and Lactic Acid Bacteria as well as the prevalence of mastitis infection using California mastitis test. The average values of pH, titrable acidity and temperatures were (6.84, 17.87°D and 36.9°C), (6.66, 18.13 °D and 37.2°C) and (6.68, 18.7°D and 37.6°C) in Oran, Relizane and Mascara farms respectively. The antibiotics residues were found in 4.76% of milk samples. The results revealed that Oran's samples recorded the highest count of FAM

Selection of Algerian lactic acid bacteria for use as antifungal bioprotective cultures and application in dairy and bakery products

In the context of a demand for “preservative-free” food products, biopreservation appears as a promising alternativeto either replace or reduce the use of chemical preservatives. The purpose of this study was to evaluatethe antifungal activity of a collection of lactic acid bacteria (n=194), and then to evaluate the applicability andefficacy of selected ones used as bioprotective cultures against mold spoilers in dairy and bakery products. First,lactic acid bacteria were isolated from various Algerian raw milk samples and Amoredj, a traditional fermentedproduct. Secondly, in vitro screening tests against Mucor racemosus UBOCC-A-109155, Penicillium communeUBOCC-A-116003, Yarrowia lipolytica UBOCC-A-216006, Aspergillus tubingensis AN, Aspergillus flavus T5 andPaecilomyces formosus AT allowed for the selection of 3 active strains, namely Lactobacillus plantarum CH1,Lactobacillus paracasei B20 and Leuconostoc mesenteroides L1. In situ tests were then performed to validate theiractivity in actual products (sour cream and sourdough bread) challenged with fungal spoilers. These testsshowed that antifungal LAB could slow the fungal target growth and could be candidates of interest for industrialapplications. Finally, organic acids and various antifungal compounds produced in sour cream and sourdoughbread by the selected LAB, and thus potentially supporting the observed antifungal activity, were identified andquantified by HPLC and LC-QTOF

Exopolysaccharide produced by Weissella confusa: Chemical characterisation, rheology and bioactivity

International audienceThe purpose of this study was to characterise the production of exopolysaccharide (EPS) by indigenous lactic acid bacteria (LAB) isolated from traditional Algerian dairy products and to evaluate their possible use in agri-foods. Among the collection of isolated strains, the strain Weissella confusa (W4) was selected for its ability to produce EPS once exposed to a sucrose culture medium. EPS produced were first isolated with a standardised method and further characterised in terms of molecular size, antioxidant activity, and rheological properties. Its direct implication in the texture and syneresis of acid milk gel was evaluated offering interesting industrial applications for its use during processes dealing with dairy products