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Cheesemaking is one of the most important industries in Mexico. Among all the Mexican cheeses, fresh cheeses are the most popular and most consumed cheese in Mexico and Latin America. However, in Mexico fresh cheese is frequently made with unpasteurized milk and sold in public markets. This may increase the risk for contamination of dairy products with pathogenic bacteria. The presence of multidrug-resistant pathogenic bacteria in food is an important public health concern. Diarrheagenic Escherichia coli pathotypes (DEPs) are foodborne bacteria. This study investigated the presence of indicator bacteria and multidrug-resistant DEPs in fresh cheeses. A total of 120 fresh cheese samples were collected from public markets in the city of Pachuca, Mexico. The samples were analyzed for presence of fecal coliforms (FC), E. coli, and antibiotic resistant DEPs. FC and E. coli were analyzed using the most-probable-number technique. DEPs were identified using two multiplex PCR methods. Susceptibility to 16 antibiotics was tested for the isolated DEPs strains by the standard assay. The frequency of FC, E. coli, and DEPs in the cheese samples was 50, 40, and 19%, respectively. The identified DEPs included Shiga toxin–producing E. coli (STEC; 8%), enteropathogenic E. coli (EPEC; 6%), and enterotoxigenic E. coli (ETEC; 5%). All isolated strains exhibited resistance to at least five antibiotics. One, one, two, and three STEC strains were resistant to 14, 12, 11, and 10 antibiotics, respectively. One strain of EPEC was resistant to 11 antibiotics, three EPEC strains to 9, and one strain to 7. One, one, and two strains of ETEC were resistant to 10, 8, and 7 antibiotics, respectively. The results of the present study indicate that fresh cheeses made with unpasteurized milk could be a risk for consumers, both for native people and visitors to Mexico. [ABSTRACT FROM AUTHOR]

The behavior of foodborne bacteria on whole and cut mangoes and the antibacterial effect of Hibiscus sabdariffa calyx extracts and chemical sanitizers against foodborne bacteria on contaminated mangoes were investigated. Mangoes var. Ataulfo and Kent were used in the study. Mangoes were inoculated with Listeria monocytogenes, Shigella flexneri, Salmonella Typhimurium, Salmonella Typhi, Salmonella Montevideo, Escherichia coli strains (O157:H7, non-O157:H7 Shiga toxin–producing, enteropathogenic, enterotoxigenic, enteroinvasive, and enteroaggregative). The antibacterial effect of five roselle calyx extracts (water, ethanol, methanol, acetone, and ethyl acetate), sodium hypochlorite, colloidal silver, and acetic acid against foodborne bacteria were evaluated on contaminated mangoes. The dry extracts obtained with ethanol, methanol, acetone, and ethyl acetate were analyzed by nuclear magnetic resonance spectroscopy to determine solvent residues. Separately, contaminated whole mangoes were immersed in five hibiscus extracts and in sanitizers for 5 min. All foodborne bacteria attached to mangoes. After 20 days at 25 ± 2°C, all foodborne bacterial strains on whole Ataulfo mangoes had decreased by approximately 2.5 log, and on Kent mangoes by approximately 2 log; at 3 ± 2°C, they had decreased to approximately 1.9 and 1.5 log, respectively, on Ataulfo and Kent. All foodborne bacterial strains grew on cut mangoes at 25 ± 2°C; however, at 3 ± 2°C, bacterial growth was inhibited. Residual solvents were not detected in any of the dry extracts by nuclear magnetic resonance. Acetonic, ethanolic, and methanolic roselle calyx extracts caused a greater reduction in concentration (2 to 2.6 log CFU/g) of all foodborne bacteria on contaminated whole mangoes than the sodium hypochlorite, colloidal silver, and acetic acid. Dry roselle calyx extracts may be a potentially useful addition to disinfection procedures of mangoes. [ABSTRACT FROM AUTHOR]

Abstract The brewers' spent grain is a by-product generated during brewery process and is a potential source for arabinoxylans (AX) extraction. In the present work, the extraction and characterization of an arabinoxylan-rich fraction from brewers' spent grain (BSG-AX) were performed, and BSG-AX was evaluated as release matrix for caffeine. The BSG-AX showed an AX content of 72% (w /w), a ferulic acid content of 3.52 μg/mg BSG-AX, an Ara/Xyl ratio of 0.89, an intrinsic viscosity of 41.18 mL g−1, and a molecular weight of 43.80 kDa. The studied BSG-AX showed a good antioxidant capacity compared with other polysaccharide gums and was estimated by DPPH (114.41 μM Trolox equivalent/g BSG-AX) and FRAP (49.01 μmol Fe2+/g BSG-AX) assays. The partial specific volume (0.63 cm3 g−1), loss on drying (10.68%), swelling (10.87%), solubility (80.93%) and electrostatic interactions (by zeta potential, −3.44 to −9.17 mV) were determined and used to evaluate the application of the BSG-AX as release matrix. A film containing the BSG-AX, glycerol (as plasticizer) and caffeine (target drug) was prepared as release matrix. Glycerol promoted an increase in the extensibility and the surface smoothness of the BSG-AX-caffeine film. The drug was released (≈98%) in about 7 h. These results are promising to concern the design and use of BSG-AX based biofilms for the controlled release of bioactive compounds. Graphical abstract Unlabelled Image Highlights • BSG-AX shows 72% of AX, and its Ara/Xyl ratio confers it a high solubility. • Ferulic acid contributes to the BSG-AX antioxidant capacity. • Loss on drying, swelling and solubility allow to evaluate the BSG-AX functions. • Glycerol contributes to obtain an extensible BSG-AX films with a smooth surface. • Caffeine release from BSG-AX film follows a non-fickian diffusion. [ABSTRACT FROM AUTHOR]