This study aims to see if probiotic bacteria from human milk could ameliorate oral cow’s milk sensitization. The probiotic potential of the SL42 strain isolated from the milk of a healthy young mother was first determined. Rats were then randomly gavaged with cow’s milk casein without an adjuvant or assigned to the control group. Each group was further subdivided into three groups, with each receiving only Limosilactobacillus reuteri DSM 17938, SL42, or a phosphate-buffered saline solution. Body weight, temperature, eosinophils, serum milk casein-specific IgE (CAS-IgE), histamine, and serum S100A8/A9 and inflammatory cytokine concentrations were measured. The animals were sacrificed after 59 days; histological sections were prepared, and the spleen or thymus weights, as well as the diversity of the gut microbiota, were measured. On days 1 and 59, SL42 abridged systemic allergic responses to casein by dropping histamine levels (25.7%), CAS-specific IgE levels (53.6%), eosinophil numbers (17%), S100A8/9 (18.7%), and cytokine concentrations (25.4–48.5%). Analyses of histological sections of the jejunum confirmed the protective effect of probiotic bacteria in the CAS-challenged groups. Lactic acid bacteria and Clostridia species were also increased in all probiotic-treated groups. These findings suggest that probiotics derived from human milk could be used to alleviate cow’s milk casein allergy.

Lactic acid bacteria (LAB): Streptococcus thermophilus TA 040 andLactobacillus delbrueckii spp. bulgaricus Lb 340, were cultured in reconstituted (10%, w/v) skimmed milk with 5 or 10% (w/v) polyfloral or unifloral honey. Inoculated samples were incubated aerobically at 42°C until milk coagulation. Samples were collected at 2 h intervals and examined for biomass and pH changes. Cell viability and post-acidifying activity of both strains during 28 days of storage at 4°C were also measured. A higher increase (P<0.05) in growth and acidifying activity of S. thermophilus monocultures was observed when 10% honey was added. However, L. bulgaricus did not show such a marked increase in its growth capacity. In associated cultures, LAB growth was slightly inhibited, whereas curdling time was prolonged by an hour when 10% honey was added and yogurt acidity was moderate. Cell viability improved by 5 to 6.6% for S. thermophilus and 10% for L. bulgaricus in pure honey-sweetened cultures over 28 days of refrigerated storage. This protective effect of honey on LAB cell viability was also observed in associated cultures (10 to 12% comparatively to the control). Key words: Streptococcus thermophilus, Lactobacillus bulgaricus, honey, growth, viability.

The goal of this study is to improve the adhesion and survival of yogurt bacteria with probiotic traits by using polysorbate 80, a food additive emulsifier commonly found in milk derivative products. Polysorbate 80 was used at 1% (w/v), and its effects on yogurt bacteria's survival under simulated digestive conditions, cholesterol uptake activities, bile salt hydrolase (BSH) activity, and adhesion to HT-29 culture were studied. In the presence of 1% polysorbate 80, both starters demonstrated better cholesterol uptake and BSH activities, as well as higher bacterial survival at pH 2.5, particularly in associated cultures. In the presence of 0.3 % bile or cholic acid, polysorbate 80 reduced the drop in L. bulgaricus's survival load. However, the carbon source had a greater impact on S. thermophilus bile tolerance than the food additive emulsifier. Oleic acid was incorporated into both bacterial membranes when grown in the presence of bile and polysorbate 80, resulting in a higher unsaturated/saturated fatty acid ratio. In the presence of polysorbate 80, S. thermophilus adhered to HT-29 cells 2.3-fold better, while L. bulgaricus's adhesion remained unchanged. We suggest that polysorbate 80 may have a protective effect on cell survival under simulated digestive stress as well as a role in yogurt bacteria adhesion to the intestines, giving these bacteria more opportunities to exert their purported cholesterol-removal activities.

Low-fat and non-fat yoghurts have some rheological changes particularly in syneresis and viscosity. Hydrocolloids such as galactomannans (locust bean gum: LBG) can act as fat replacers and can improve the rheological properties of low and non-fat yoghurts. The present study investigates the effect of carob galactomannans on both the viability of starter cultures and textural properties of non-fat yoghurt during cold storage period (4 °C). Carob galactomannans were extracted from carob seeds. Yoghurt was made from skimmed milk powder with the addition of starter culture and locust bean gum at different concentrations (0.01, 0.02, 0.05 and 0.1% W/V). The yoghurt was stored for 28 days at 4°C. Changes in starter microorganisms’ viability, pH, viscosity and syneresis were measured after 24h of manufacturing than every 7 days. Results showed that starter culture microorganisms (Streptococcus thermophilus and Lactobacilus bulgaricus) showed better (P<0.05) retention of viability in yoghurt supplemented with galactomannans (0.05 and 0.1%) in comparison with control. LBG did not showed a significant (P<0.05) effect on pH changes during refrigerated storage of yoghurt. However its hydrocolloid improved (P<0.05) the viscosity and prevented the defect of syneresis during storage at 4°C. Additionally, panelists preferred yoghurt sample with 0.05% LBG. This suggests that these polysaccharides can be used as fat replacers to reduce the problems associated with elimination of fat in fermented dairy products.