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This study aimed to produce probiotic ‘Testouri’, traditional Tunisian sheep cheese, by direct-to-vat inoculum of probiotic adjuncts.The potential of Testouri sheep cheeses was evaluated by an assessment of gross composition and proteolytic, antibacterial, antidiabetic and antioxidant activities during storage at 4 °C for 28 days. Results highlighted that no significant differences were observed in compositional parameters of the samples at day 0. Probiotic counts in cheeses remained at 8 log CFU g−1 during storage. Probiotic cheeses exhibited measurable antibacterial activities with the maximum value (diameter of 12 ± 0.07 mm) on Staphylococcus aureus strain. Also, α-glucosidase and α-amylase inhibitions ranged from 42 ± 0.77 to 58 ± 0.88% and 20 ± 0.9 to 47 ± 1.3%, respectively, during storage. Additionally, cheeses inoculated with probiotics exhibited significant increases in proteolytic and antioxidant activities compared to the control sample.Therefore, Testouri cheese can be considered a good carrier of probiotics and can be promoted for commercial uses.

The present work focused on the effects of the Modified Atmosphere Packaging (MAP) 1 (5% O2 and 10% CO2) or 2 (2% O2 and 5% CO2) and the previous addition of Lactoperoxidase System (LPS) and Oregano essential oil or chlorine washing on the quality of fresh-cut lettuce during refrigerated storage at +4˚C. Our results showed the significant effect of this combined treatment on quality improvement during storage. Thus, mesophilic bacteria was reduced in treated samples compared to those untreated with number which not exceeded the critical of 5 × 107 UFC∙g-1 (p 0.05). Brightness of lettuce samples was significantly reduced during storage. Thereafter, the PCA data showed the effect of combined treatment on the preservation of hygienic, physico-chemical and sensory quality up to the 7th day of refrigerated storage of these treated samples. The results obtained draw attention to modified atmosphere packaging lettuce and the addition of bio-preservatives which could be an alternative of choice to replace chlorine to preserve the sanitary quality of green products.

One hundred strains isolated from bovine raw milk, obtained from different farms, were subjected to different in vitro stress typical of gastrointestinal tract. Twelve strains were able to tolerate pepsin at pH 2, pancreatin and bile salts (0.3%). These bacteria were identified using 16S rRNA gene sequencing. Eight isolates were Lactobacillus plantarum and four were Lactobacillus fermentum. They were not able to degrade mucin and they were γ-haemolytic. All strains had antibacterial activity against Staphylococcus aureus, Listeria monocytogenes and Salmonella thyphimirium. However, only six strains inhibited Escherchia coli. All these showed ability for autoaggregation and/or hydrophobicity properties. They were also characterized in respect to their technological properties. Important acidification and low proteolytic and lipolytic capacities were detected for all strains. In addition, they were able to produce exopolysaccharides and grow at hot and cold temperatures. These bacteria may be used further for manufacturing of functional foods and confirming their suitability as probiotic starter cultures.

In the present study, 20 selected Lactobacillus strains already characterized in a previous research for their capability to grow in conditions simulating the intestinal environment, their resistance to antibiotics, their antibacterial activity and their adhesion capability to intestinal human Caco-2 TC7 and HT-29 MTX cell lines, were further investigated to explore more their probiotic properties. Growth behaviour in the presence of prebiotic (fructooligosac-charides (FOS) and lactulose) at a concentration of 2%, cholesterol removal by measuring the residual cholesterol in medium supplemented with cholesterol, ability to deconjugate bile salts using BSH enzyme and antioxidant activity of culture supernatant of Lactobacillus strains by ABTS·+ and DPPH methods were analyzed. All probiotic strains demonstrated important prebiotic assimilation (P > 0.05) even with OD600 > 3 after 30 h of contact, cholesterol removal ability with maximum percentage of 57% after 24 h of contact and they were found to liberate significantly (P < 0.05) more cholic acid with maximum of 0.40 mM of sodium glycocholate, 0.33 mM of sodium taurocholate and 0.41 mM of their mixte and scavenge both radicals with 52% and 2.19% of ABTS·+ and DPPH respectively. This study confirmed the suitability of these probiotic strains for application in functional food formulations especially where cholesterol reduction and antioxidant activity in food are needed to assess possible in vivo human health benefits.

Tweenty probiotic lactic acid bacteria (LAB) strains from Tunisian camel raw milk were identified among a collection of 177 isolates. The selected strains were able to tolerate pH 2, pepsin, pancreatin and bile salts, as restrictive criteria for probiotic potential. LAB strains were identified using 16S rRNA gene sequencing. Fourteen isolates belonged to the species Lactobacillus fermentum and six to Lactobacillus plantarum. None of this LAB showed mucin degradation or hemolytic activity, while proving resistant to a series of clinically antibiotics. All strains have antibacterial activity against Listeria monocytogenes, Staphylococcus aureus and Escherchia coli. However, only 18 strains inhibited Salmonella thyphimirium. The L. fermentum strains showed an important level of adhesion to human Caco-2 and HT29-MTX epithelial cells. Our work suggests that camel raw milk is valuable source of probiotic bacteria with functional characters of intestinal lactobacilli. These bacteria may be further used in probiotic applications.