Thermal pasteurization can achieve the U. S. Food and Drug Administration-required 5-log reduction of pathogenic Escherichia coli O157:H7 and Cryptosporidium parvum in apple juice and cider, but it can also negatively affect the nutritional and organoleptic properties of the treated products. In addition, thermal pasteurization is only marginally effective against the acidophilic, thermophilic, and spore-forming bacteria Alicyclobacillus spp., which is known to cause off-flavors in juice products. In this study, the efficiency of a combined microfiltration (MF) and UV process as a nonthermal treatment for the reduction of pathogenic and nonpathogenic E. coli, C. parvum, and Alicyclobacillus acidoterrestris from apple cider was investigated. MF was used to physically remove suspended solids and microorganisms from apple cider, thus enhancing the effectiveness of UV and allowing a lower UV dose to be used. MF, with ceramic membranes (pore sizes, 0.8 and 1.4 μm), was performed at a temperature of 10 °C and a transmembrane pressure of 155 kPa. The subsequent UV treatment was conducted using at a low UV dose of 1.75 mJ/cm(2). The combined MF and UV achieved more than a 5-log reduction of E. coli, C. parvum, and A. acidoterrestris. MF with the 0.8-μm pore size performed better than the 1.4-μm pore size on removal of E. coli and A. acidoterrestris. The developed nonthermal hurdle treatment has the potential to significantly reduce pathogens, as well as spores, yeasts, molds, and protozoa in apple cider, and thus help juice processors improve the safety and quality of their products.
Background Agro-industrial waste from tropical environments could be an important source of lactic acid bacteria (LAB) with probiotic potential. Methods Twelve LAB isolates were isolated from pineapple silages. The species identification was carried out considering 16S rRNA and pheS genes. Experiments to evaluate the probiotic potential of the isolates included survival under simulated gastrointestinal environment, in vitro antagonistic activity (against Salmonella spp. and Listeria monocytogenes), auto-aggregation assays, antibiotic susceptibility, presence of plasmids, adhesiveness to epithelial cells, and antagonistic activity against Salmonella in HeLa cells. Results Lacticaseibacillus paracasei, Lentilactobacillus parafarraginis, Limosilactobacillus fermentum, and Weissella ghanensis were identified. Survival of one of the isolates was 90% or higher after exposure to acidic conditions (pH: 2), six isolates showed at least 61% survival after exposure to bile salts. The three most promising isolates, based on survivability tests, showed a strong antagonistic effect against Salmonella. However, only L. paracasei_6714 showed a strong Listeria inhibition pattern; this isolate showed a good auto-aggregation ability, was resistant to some of the tested antibiotics but was not found to harbor plasmids; it also showed a high capacity for adhesion to epithelial cells and prevented the invasion of Salmonella in HeLa cells. After further in vivo evaluations, L. paracasei_6714 may be considered a probiotic candidate for food industry applications and may have promising performance in acidic products due to its origin.
La presencia de gluten en alimentos etiquetados como libres de gluten (LG) representa una preocupación para la salud de pacientes celíacos, y personas intolerantes y sensibles a este conjunto de proteínas. Sin embargo, esto no ha sido estudiado aún en países centroamericanos. Por tanto, se investigó la presencia de gluten en alimentos etiquetados LG, manufacturados en Costa Rica y disponibles en el mercado entre los años 2016 y 2017 para determinar así el cumplimiento de las regulaciones nacionales e internacionales. Se ha estipulado que dichos alimentos deben contener <20 ppm de gluten. Un total de 173 productos fueron analizados por inmunoensayo (tres muestras por producto; cada una de un lote diferente) utilizando el kit ELISA RIDASCREEN®. 60 marcas de productos, de 32 compañías diferentes, fueron evaluadas identificando 15 categorías de alimentos LG: productos horneados, premezclas y harinas, snacks, granos y cereales, salsas, productos cárnicos, productos de origen marino, bebidas, productos lácteos, pastas, chocolates, aceites, tortillas y arepas, jaleas y mermeladas y otros. Una muestra de uno de los productos analizados presentó >20 ppm de gluten. No obstante, al menos una muestra de 49 productos diferentes (28% de los productos analizados) presentó una concentración cuantificable de gluten (>5 ppm) evidenciando una alta variabilidad en los resultados. Esta investigación evidencia el fuerte compromiso de la industria alimentaria costarricense para cumplir la norma que regula la producción de alimentos LG durante el período de estudio, aunque se alerta acerca de la necesidad de implementar mejoras en los sistemas de producción y vigilancia de estos alimentos. The presence of gluten in gluten free (GF) labelled foods represents a serious health concern to celiac patients and persons intolerant or sensitive to this set of proteins. However, this has not yet been studied in Central American countries. Therefore, the presence of gluten in foods labeled LG, manufactured in Costa Rica and available in the market, between 2016 and 2017, was investigated to determine compliance with national and international regulations. It has been stipulated that such foods must contain <20 ppm of gluten. A total of 173 products were analyzed by immunoassay (three samples per product; each from an independent batch), using the ELISA RIDASCREEN® kit. 60 product brands, from 32 different companies, were evaluated and 15 GF food categories were identified: baked products, baking mixes and flours, snacks, grains and cereals, sauces, meat products, seafood, beverages, dairy products, pasta, chocolates, oils, tortillas and arepas, jams and jellies, and others. Only one sample from one of the tested products presented >20 ppm of gluten. However, at least one sample of 49 different products (28% of products tested) presented a quantifiable concentration of gluten (>5 ppm), showing a high variability of results. This research evidences the strong commitment of the Costa Rican food industry to comply with the norm that regulates the production of LG foods during the study period, even though it warns about the need to implement improvements in the production and surveillance systems of these foods.
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