Increase in awareness of the health benefits of vegetables has resulted in an increase in consumption. Many vegetables are consumed raw to retain the natural taste and heat labile nutrients. The safety of raw vegetables is a great concern. We investigated the bacteriological and parasitological quality of salad vegetables sold in three major markets in Fako Division Cameroon, the hygiene and preservation practices of vendors and determined the antimicrobial sensitivity of bacterial isolates, to provide data that could be used to improve food safety and safeguard public health. Bacterial contamination was high. Mean aerobic bacteria counts ranged from 2.5 × 106 to 15 × 106 cfu/g, total coliform counts from 4 to > 2400/g and fecal coliforms < 3 to 1100/g. Six bacterial species were isolated among which Staphylococcus aureus (35.4%) predominated while Serratia marcescens (8.5%) was the least. Bacteria showed high resistance to erythromycin (87.6%). Ten parasitic organisms were detected. Balantidium coli (25.6%) and Entamoeba spp. (21.7%) predominated. Contamination was highest in lettuce and lowest in green pepper. Hygiene and vegetable preservation practices of vendors were poor and could aggravate contamination. Contamination of fresh salad vegetables with pathogenic bacteria and parasites could be a food safety concern in study area.

High serum cholesterol is a risk factor for cardiovascular disease (CVD), leading to many fatalities. Traditional palm wine (Elaeis guineensis) and corn beer are noted as potential sources of probiotic bacteria with cholesterol lowering activity. In this study, we isolated and characterised lactic acid bacteria (LAB) with probiotic and cholesterol lowering properties from these sources. The isolates were identified using API 50 CHL kit and sequencing of 16 S rRNA gene. A hypercholesterolemia model involving three groups of eighteen diet-induced Wistar albino rats was established, and the serum lipid profile was analysed using biochemical kits. The genotypic identification of two best cholesterol lowering LAB revealed that they were strains of Levilactobacillus brevis and Enterococcus faeccium. Their 16 S r RNA gene sequences were deposited in NCBI genbank with the accension numbers ON454506 and ON908682 respectively. These isolates effectively lowered LDL-c and increased HDL-c in rat sera, which are the main risk factors for CVD. These probiotics are potential candidates for functional foods formulation against hypercholesterolemia.

Interactions occurring between Saccharomyces cerevisiae and two thermostable α-amylase producing strains (Bacillus amyloliquefaciens 04BBA15 and Lactobacillus fermentum 04BBA19) were analyzed by comparing their growth patterns obtained in isolation with those obtained in mixture. The difference between the patterns was assessed using analysis of variance (ANOVA) in order to measure how much the growth of an organism was affected by other. The results showed two types of interactions in mixed culture; commensalism between S. cerevisiae and B. amyloliquefaciens 04BBA15 and mutualism between S. cerevisiae and L. fermentum 04BBA19. In mixed culture, the α-amylase production increased significantly compared to that observed in monoculture (P < 0.05). Response surface optimization of fermentation parameters in mixed cultures (initial yeast to bacteria ratio 1.125, temperature 33.5 °C, pH 5.5) resulted in about 1.8 fold higher enzyme production than that observed in the unoptimized fermentation.

The commonly used probiotics bacteria are lactic acid bacteria (LAB) from gastro intestinal tract. However, other LAB from exogenous origin having similar functional properties may also confer health benefit to the host. Palm wine has been described as a rich source of LAB. But very few studies have investigated their probiotic potential. Twenty LAB were isolated from palm wine collected in the South West Region of Cameroon by pour plate method on MRS agar. These isolates were assessed in vitro for their potential to inhibit the growth of some foodborne pathogens, mainly Salmonella sp. and Escherichia coli using disc diffusion method. Acid and bile tolerance were evaluated by measuring the survival rate of LAB after incubation at pH range from 1.0 to 3.0 and various bile salt concentrations (0.15-0.30%). Only five isolates were selected based on their potential to inhibit food borne pathogens tested and their tolerance in acid and bile. They were identified using API kit 50 CHL BioMerieux as strains of Lactobacillus pentosus, Lactobacillus plantarum and Lactobacillus brevis. All these strains showed antimicrobial activity against strains of Salmonella sp. and E. coli with diameters of inhibition varying from 12 to 20 mm. Only L. pentosus and L. brevis1 tolerated pH 3.0 (acidic condition of interest) with survival rates of 55 and 69% respectively, while all survived in bile with survival rates above 60%. Key words: Probiotics, antimicrobial activity, acid tolerance, bile tolerance.