Identification of Dairy Fungal Contamination and Reduction of Aflatoxin M1 Amount by Three Acid and Bile Resistant Probiotic Bacteria.

Aflatoxins (AFs) released by fungi are observed in the cow’s milk even after pasteurization. Aflatoxin M1 (AFM1) has particularly an incredible clinical significance, as a critical carcinogenic agent for humans. Several strategies have been implemented for lowering the AFM1 amount, such as the employment of probiotics, particularly lactobacilli or lactic acid bacteria (LAB). However, this strategy has not been applied routinely until today. This study aimed to evaluate the effect of three LABs on the reduction of AFM1 in traditional milk and cheese samples. In total, 85 milk (n=45) and cheese (n=40) samples were obtained from the open markets of Shiraz, Iran, from February to June 2018. Additionally, the AFM1 levels were evaluated, compared to those of the National Iranian Standard. The data were then analyzed in SPSS software (version 20) through the Chi-square test. Statistical analysis was performed at a 95% confidence level (p-value of <0.00001). Out of 50 purchased LABs, the efficient antifungal property and resistance to bile salts were observed in five strains. The mean value of these five strains was calculated after adding 5 ppm AFM1, compared to natamycin. The strains with a reduction in AFM1 level were sequenced and registered in the NCBI database.In total, 15 samples with contamination higher than the allowed limit included Penicillium spp, Aspergillus niger, Saccharomyces cerevisia, Saccharomyces paradoxus, and Yarrowia lipolytica.The results also showed reduced AFM1 levels in three LAB-treated strains. Lactobacillus fermentum CECT562 (T), Lactobacillus brevis ATCC14869 (T), and Enterococcus faecium LMG 11423 (T) had this capability to 0.05, 0.03, and 0.03 respectively. The National Iranian Standard should be implemented to have control over traditional dairy products with more care. The three LABs selected in the current study revealed a significant effect on reducing AFM1 levels in traditional milk and cheese.

Heat-killed probiotic bacteria induce apoptosis of HT-29 human colon adenocarcinoma cell line via the regulation of Bax/Bcl2 and caspases pathway.

Apoptosis induction in cancer cells is one of the most efficient ways to treat cancer and find anticancer compounds. The aim of this study was to evaluate the cytotoxic effects of heat-killed indigenous probiotic bacteria and apoptosis induction in the HT-29 human colon adenocarcinoma cell line. The growth-inhibitory effects of probiotic heat-killed Lactobacillus brevis and Lactobacillus paracasei isolated from the traditional Iranian food "Terxine" on the HT-29 cell line were determined by 3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry by Annexin-FITC kit, DNA fragmentation assay, 4,6-diamidino-2-phenylindole staining, and the expression of Bax, Bcl2, caspase-3, and caspase-9 were used to analyze apoptosis. MTT results demonstrated that the heat-killed bacteria inhibited the proliferation of HT-29 cells and induced apoptosis in a time-, dose-, and strain-dependent manner. The results demonstrated that both bacteria could induce apoptosis in the HT-29 cell line. Heat-killed probiotic bacteria increased the expression of Bax, caspase-3, and caspase-9 mRNA levels in HT-29 cell lines. Also, heat-killed probiotic bacteria reduced the expression of Bcl2 in HT-29 cells. The heat-killed probiotic bacteria in this study exhibited potent growth inhibitory effects on cancer cells. The results demonstrated that L. brevis has a greater ability to inhibit the growth of HT-29 cells and induce apoptosis, compared with L. paracasei. It is proposed that these bacteria can be used as biological products for the treatment and prevention of cancer, pending further investigation.

In vitro removal of polycyclic aromatic hydrocarbons by lactic acid bacteria.

AIMS: The current study aimed to investigate the ability of lactic acid bacteria (LABs) in removing four polycyclic aromatic hydrocarbons (PAHs) namely, benzo(a)pyrene (BaP), benz(a)anthracene (BaA), chrysene (Chr) and benzo(b)fluoranthene (BbF) from contaminated phosphate buffer saline (PBS). METHOD AND RESULTS: The effect of initial PAH concentrations (5, 10, 15, 20 µg ml-1 ), bacterial population (107 , 108 , 109 , 1010 CFU per ml) and pH (3, 5, 7) was studied to evaluate bacterial binding ability. All the tested bacteria could remove BaA, Chr, BbF and BaP from phosphate buffer solution and in almost all assays, removing of PAHs was as follows: BaP>Chr>BaA>BaF. Bifidobacterium lactis BB-12 had the lowest binding rate for all four PAHs, while the highest binding ability was related to Lactobacillus acidophilus LA-5. Moreover, cell viability was not required for the binding ability and even acid-treated, heat-treated and ultrasonic-treated bacterial cells showed more binding ability. The results showed that the bacteria-PAH complex was irreversible after washing with PBS. CONCLUSIONS: The removal of PAHs was significantly related to pH of media, strains of bacteria, type and concentration of PAHs SIGNIFICANCE AND IMPACT OF THE STUDY: This study has been focused on the reduction of polycyclic aromatic hydrocarbons using LABs and probiotics. Our results showed that not only live strains but also inactivated tested strains are able to remove PAHs from aqueous media, presenting new methods to diminish the amount of these contaminants in foods. Furthermore, the results of this study can be used in future research on evaluating the effects of oral administration of probiotic supplements and even dead probiotic strains on reducing PAHs in humans.

A Randomized Controlled Clinical Trial Investigating the Effect of Synbiotic Administration on Markers of Insulin Metabolism and Lipid Profiles in Overweight Type 2 Diabetic Patients with Coronary Heart Disease.

Objective: The current study was performed to evaluate the effects of synbiotic administration on metabolic profiles in overweight diabetic patients with coronary heart disease (CHD). Methods: This randomized, double-blind, placebo-controlled trial was done among 60 diabetic patients with CHD. Participants were randomly divided into 2 groups: group A (n=30) received synbiotic supplements containing 3 probiotic bacteria spices Lactobacillus acidophilus 2×109, Lactobacillus casei 2×109, Bifidobacterium bifidum 2×109 CFU/g plus 800 mg inulin and group B (n=30) received placebo for 12 weeks. Fasting blood samples were taken at baseline and after 12-week intervention to determine metabolic profiles. Results: After 12 weeks of intervention, patients who consumed synbiotic capsule had significantly decreased fasting plasma glucose (- 19.6±74.6 vs.+19.2±66.9 mg/dL, P=0.03), serum insulin concentrations (- 0.7±5.1 vs.+3.3±6.3 µIU/mL, P=0.01), the homeostasis model of assessment-estimated b cell function (- 3.4±19.5 vs.+11.5±21.0, P=0.006) and increased the quantitative insulin sensitivity check index (+ 0.002±0.01 vs.-0.01±0.02, P=0.03) compared with the placebo. In addition, changes in HLDL-cholesterol levels (+ 1.8±5.7 vs.-2.2±6.0 mg/dL, P=0.01) in supplemented patients were significantly different from those of patients in the placebo group. Conclusion: Synbiotic supplementation for 12 weeks among diabetic patients with CHD had beneficial effects on markers of insulin metabolism and HDL-cholesterol levels.

Effects of probiotic supplementation on glycaemic control and lipid profiles in gestational diabetes: A randomized, double-blind, placebo-controlled trial.

BACKGROUND: To our knowledge, data on the effects of probiotic supplementation on glycaemic control and lipid concentrations in patients with gestational diabetes mellitus (GDM) are scarce. AIM: The aim of the present study was to determine the effects of probiotic supplementation on glycaemic control and lipid profiles in GDM patients. METHODS: Sixty pregnant women with GDM, primigravida and aged 18-40years, were divided into two groups to receive either probiotic capsules (n=30) or a matching placebo (n=30) in this randomized double-blind, placebo-controlled trial. The patients in the probiotic group took a daily capsule that contained three viable freeze-dried strains: Lactobacillus acidophilus (2×10(9)CFU/g), L. casei (2×10(9)CFU/g) and Bifidobacterium bifidum (2×10(9)CFU/g) for 6weeks. The placebo group took capsules filled with cellulose for the same time period. Fasting blood samples were taken at the beginning and end of the study to quantify the relevant markers. RESULTS: After 6weeks of intervention, probiotic supplementation vs a placebo resulted in significant decreases in fasting plasma glucose (-9.2±9.2mg/dL vs +1.1±12.2mg/dL, P<0.001), serum insulin levels (-0.8±3.1µIU/mL vs +4.5±10.6µIU/mL, P=0.01), homoeostasis model assessment (HOMA) for insulin resistance (-0.4±0.9 vs +1.1±2.5, P=0.003) and HOMA for ß-cell function (+1.1±9.8 vs +18.0±42.5, P=0.03), and a significant increase in the quantitative insulin sensitivity check index (+0.007±0.01 vs -0.01±0.02, P=0.007). In addition, significant decreases in serum triglycerides (-1.6±59.4mg/dL vs +27.1±37.9mg/dL, P=0.03) and VLDL cholesterol concentrations (-0.3±11.9mg/dL vs +5.4±7.6mg/dL, P=0.03) were seen following supplementation with the probiotics compared with the placebo. However, no significant changes in other lipid profiles were seen with the intervention. CONCLUSION: Overall, the results of our study have demonstrated that taking probiotic supplements for 6weeks in patients with GDM had beneficial effects on glycaemic control, triglycerides and VLDL cholesterol concentrations, although there was no effect on other lipid profiles.