Patricia Castellano

Listeria monocytogenes is a foodborne pathogen able to survive, proliferate at refrigeration temperatures and contaminate a wide variety of foods, particularly chilled meat and ready-to-eat (RTE) meat products. One of the major challenges for the food industry in preventing the proliferation of spoilage and pathogen microorganisms lies in food packaging innovation. In this study, edible films were developed to control Listeria monocytogenes in cooked ham. An active film with antimicrobial properties was formulated from high-methoxyl pectin (HMP) and lactocin AL705 (AL705), a bacteriocin produced by Latilactobacillus (Lat.) curvatus CRL705. The optical, mechanical, and antimicrobial properties of the edible films were measured to determine the effects of AL705 on the film matrix. The minimum inhibitory concentration (MIC) of the bacteriocin used for film activation was 1.25 mg/mL. The incorporation of AL705 into the films did not significantly affect (p ≥ 0.05) moisture content, color parameters (L*, a*, DE*), elongation at break, or tensile strength compared with control films (HMP/Control). However, HMP/AL705 films exhibited lower water vapor permeability (p ≤ 0.05) and reduced transparency. The incorporation of AL705 did not significantly alter peak intensity or generate new peaks in the FTIR spectra. SEM micrographs revealed surface modifications in films containing bacteriocin AL705 compared with the control films. In edible films activated with AL705 at 4 °C, the growth of L. monocytogenes was completely inhibited in cooked ham for 7 days. Although the Listeria load increased toward day 14, it remained satisfactorily controlled in samples treated with HMP/AL705 films compared with samples treated with HMP/Control films. A similar trend was observed at 10 °C, which was used as the abuse temperature. Therefore, HMP films incorporated with lactocin AL705 may represent a promising alternative for functional food packaging aimed at improving food preservation.

En México existe una gran diversidad de bebidas fermentadas que se elaboran de forma artesanal; muchas de ellas han sido caracterizadas y cuentan con denominación de origen. Sin embargo, son poco documentadas y son conocidas únicamente en sus comunidades de origen. Es por ello por lo que este estudio se enfoca en el análisis de la bebida tradicional Caxtila, elaborada en la comunidad de Ixpaluca y otras localidades del municipio de Zongolica, Veracruz. Caxtila se destaca entre la diversidad de bebidas tradicionales de la región debido a los atributos benéficos que los pobladores le confieren, así como el valor cultural que la destaca. Se elabora a base de jugo de caña, arroz tostado y raíz de timbre (Acaciella angustissima), mediante un proceso de fermentación alcohólica. Durante los primeros días de fermentación, la bebida puede consumirse como “agua de tiempo”, aprovechando sus propiedades nutricionales. El proceso completo dura aproximadamente cinco días, dando como resultado una bebida refrescante, bajo contenido alcohólico y rico en azúcares, ideal para los días calurosos. Su demanda es alta en abril, mayo y junio. Este estudio tuvo como objetivo generar evidencia científica sobre las propiedades del Caxtila. Para ello, se realizó una caracterización fisicoquímica, evaluando parámetros como pH, °Brix, porcentaje de alcohol, humedad, cenizas, sólidos totales; además del tiempo de fermentación y la temperatura. Se analizaron muestras elaboradas por dos productores distintos, encontrando que, aunque las bebidas presentaban características sensoriales similares, presentaban variaciones en el contenido de humedad, sólidos totales y cenizas. Los resultados permiten visibilizar el valor funcional del Caxtila y abren la posibilidad de impulsar su aprovechamiento funcional; sin embargo, es necesario estandarizar los procesos de elaboración para garantizar la calidad del producto y fomentar su comercialización, respetando al mismo tiempo su origen cultural y artesanal.

Listeriosis is a disease associated with the consumption of food contaminated with Listeria monocytogenes. Probiotic lactic acid bacteria (LAB) or their postbiotics have been of interest for their anti-listerial effect. This study focused on isolating LAB from artisanal cheeses and characterizing their potential as probiotics. Twelve LAB isolates exhibiting typical LAB traits were evaluated for their ability to survive in simulated gastric juice, hydrolyze bile salts, auto-aggregate, hydrophobicity, and antagonistic activity against L. monocytogenes. The four most promising LAB strains demonstrated anti-listerial probiotic potential and were identified as Latilactobacillus (Lat.) curvatus SC076 and Lactiplantibacillus (Lact.) paraplantarum SC291, SC093, and SC425. The antimicrobial activity of these strains was mainly attributed to bacteriocin-like substances and organic acids. While three Lact. paraplantarum strains were resistant to ampicillin, Lat. curvatus was sensitive to all tested antibiotics. All selected strains exhibited no hemolytic, gelatinase, and lecithinase activity. Exposure to LAB supernatants resulted in a significant reduction in the adhesion and intracellular count of L. monocytogenes in Caco-2 cells, with Lat. curvatus SC076 showing the most significant effect. Based on its probiotic characteristics, Lat. curvatus SC076 is a promising candidate for functional foods, pending further in vivo studies to assess its potential in the food industry.

The lactic acid bacteria (LAB) communities that develop in traditional meat fermented products are a result of the stressful environmental conditions that exist during meat fermentation. In traditional fermented sausages, Latilactobacillus (L.) sakei and L. curvatus are by far the most often isolated species among LAB, but Lactiplantibacillus plantarum and species from Enterococcus and Pediococcus have also been isolated and/or used as starter cultures. L. sakei and L. curvatus are emblematic meat LAB considered the core functional bacteria in meat fermentation; their important role in meat technology, competitiveness for meat growth, acid production, protein degradation, and bio-preservative potential, as well as genomic diversity and proteomic profiles, are discussed herein. The feasibility to use fermented sausages as a vehicle of probiotics is also approached. Fermented sausages are unique products, often represented as elements of food heritage and identity. To deal with a threatening and globalizing trend, contemporary food markets rely on the oxymoronic concept of innovation though tradition. Since the prevailing microbiota of traditional fermented sausages seem to be associated with desirable aspects, using autochthonous and carefully selected LAB as starter cultures with specific functionalities could contribute to preserving typicality with benefits for both producers and consumers.

The administration of goat milk fermented (FGM) with Lactobacillus delbrueckii subsp. indicus CRL1447 and supplemented with different mixes of lactobacilli strains (Mix1: Limosilactobacillus fermentum CRL1446 + Lactiplantibacillus paraplantarum CRL1449 + Lactiplantibacillus paraplantarum CRL1472; Mix2: CRL1446 + CRL1449; Mix3: CRL1446 + CRL1472; and Mix4: CRL1449 + CRL1472) was investigated regarding body weight, metabolic and inflammatory parameters, and gut microbiota (GM) composition in mice fed a high-fat diet (HFD). Body weight gain, adipocyte size, fasting blood glucose, serum triglyceride, and leptin levels were significantly reduced in the group fed FGM+Mix3 compared with the obese mice fed FGM. FGM+Mix2 and FGM+Mix3 modified the GM composition, reversing the dysbiosis caused by the HFD. Although there were no significant changes at the phylum level, the GM composition was significantly changed at the family and genus levels. Results suggest that the administration of FGM+Mix3 improves metabolic and immune profiles in obese mice while positively modulating the GM, therefore attenuating the risk factors associated with obesity.