Estudio de los factores que determinan la respuesta de adaptación ácida y de protección cruzada frente al calor de Salmonella Typhimurium y Salmonella Senftenberg: mecanismos implicados = Factors influencing the acid tolerance and cross-protection responses of "Salmonella" Typhimurium and "Salmonella" Senftenberg: mechanisms involved

230 p.Este trabajo de investigación se ha centrado en determinar la respuesta frente al estrés ácido de dos serovariedades del género Salmonella, de gran interés sanitario y tecnológico, S. Typhimurium y S. Senftenberg, en presencia de diversos ácidos orgánicos de uso habitual en la industria alimentaria. Los resultados obtenidos han permitido demostrar que la adaptación de ambas serovariedades en ambientes ácidos moderados origina respuestas adaptativas de tolerancia ácida, que se manifiestan por un incremento de su subsecuente resistencia a condiciones ácidas letales, y de protección cruzada frente a tratamientos térmicos, tanto en medios de laboratorio como en zumos de naranja y manzana. Asimismo hemos comprobado que diversos parámetros ambientales, como la temperatura de crecimiento, la composición del medio de cultivo y tratamiento, o el tipo de ácido utilizado, condicionan la expresión y la magnitud de dichas respuestas adaptativa

Application of lactic acid bacteria for the biopreservation of meat products: A systematic review

Systematic ReviewThe increasing concern of consumers about food quality and safety and their rejection of chemical additives has promoted the breakthrough of the biopreservation field and the development of studies on the use of beneficial bacteria and their metabolites as potential natural antimicrobials for shelf life extension and enhanced food safety. Control of foodborne pathogens in meat and meat products represents a serious challenge for the food industry which can be addressed through the intelligent use of bio-compounds or biopreservatives. This article aims to systematically review the available knowledge about biological strategies based on the use of lactic acid bacteria to control the proliferation of undesirable microorganisms in different meat products. The outcome of the literature search evidenced the potential of several strains of lactic acid bacteria and their purified or semi- purified antimicrobial metabolites as biopreservatives in meat products for achieving longer shelf life or inhibiting spoilage and pathogenic bacteria, especially when combined with other technologies to achieve a synergistic effect.S

Whole Resistome Analysis in Campylobacter jejuni and C. coli Genomes Available in Public Repositories

-Campylobacter spp. are the most frequent agent of human gastroenteritis worldwide, and the spread of multidrug-resistant strains makes the clinical treatment difficult. The current study presents the resistome analysis of 39,798 Campylobacter jejuni and 11,920 Campylobacter coli genomes available in public repositories. Determinants of resistance to β-lactams (Be) and tetracyclines (Te) were the most frequent for both species, with resistance to quinolones (Qu) as the third most important on C. jejuni and to aminoglycosides (Am) on C. coli. Moreover, resistance to Te, Qu, and Am was frequently found in co-occurrence with resistance to other antibiotic families. Geographical differences on clonal complexes distribution were found for C. jejuni and on resistome genotypes for both C. jejuni and C. coli species. Attending to the resistome patterns by isolation source, three main clusters of genomes were found on C. jejuni genomes at antimicrobial resistance gene level. The first cluster was formed by genomes from human, food production animals (e.g., sheep, cow, and chicken), and food (e.g., dairy products) isolates. The higher incidence of tet(O), associated with tetracycline resistance, and the gyrA (T86I) single-nucleotide polymorphism (SNP), associated with quinolone resistance, among genomes from this cluster could be due to the intense use of these antibiotics in veterinary and human clinical settings. Similarly, a high incidence of tet(O) genes of C. coli genomes from pig, cow, and turkey was found. Moreover, the cluster based on resistome patterns formed by C. jejuni and C. coli genomes of human, turkey, and chicken origin is in agreement with previous observations reporting chicken or poultry-related environments as the main source of human campylobacteriosis infections. Most clonal complexes (CCs) associated with chicken host specialization (e.g., ST-354, ST-573, ST-464, and ST-446) were the CCs with the highest prevalence of determinants of resistance to Be, Qu, and Te. Finally, a clear trend toward an increase in the occurrence of Te and Qu resistance determinants on C. jejuni, linked to the spread of the co-occurrence of the bla OXA−61 and tet(O)-tet(O/W/O) genes and the gyrA (T86I) SNP, was found from 2001 to date in Europe.S

Application of lactic acid bacteria for the biopreservation of meat products: A systematic review

.The increasing concern of consumers about food quality and safety and their rejection of chemical additives has promoted the breakthrough of the biopreservation field and the development of studies on the use of beneficial bacteria and their metabolites as potential natural antimicrobials for shelf life extension and enhanced food safety. Control of foodborne pathogens in meat and meat products represents a serious challenge for the food industry which can be addressed through the intelligent use of bio-compounds or biopreservatives. This article aims to systematically review the available knowledge about biological strategies based on the use of lactic acid bacteria to control the proliferation of undesirable microorganisms in different meat products. The outcome of the literature search evidenced the potential of several strains of lactic acid bacteria and their purified or semi-purified antimicrobial metabolites as biopreservatives in meat products for achieving longer shelf life or inhibiting spoilage and pathogenic bacteria, especially when combined with other technologies to achieve a synergistic effect.S

Effect of Non-Thermal Atmospheric Plasma on Food-Borne Bacterial Pathogens on Ready-to Eat Foods: Morphological and Physico-Chemical Changes Occurring on the Cellular Envelopes

[EN] Currently, there is a need for new technological interventions to guarantee the microbiological safety of ready-to-eat (RTE) foods. Non-thermal atmospheric plasma (NTAP) has emerged as a promising strategy for inactivating microorganisms on thermo-sensitive foods, and the elucidation of its mechanisms of action will aid the rational optimization and industrial implementation of this technology for potential applications in the food industry. In this study, the effectiveness of NTAP for inactivating strains of Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes contaminating the surface of different sliced RTE foods (“chorizo”, salami, bacon, smoked salmon, tofu and apple) was investigated. In addition, to further assess the bacterial inactivation mechanisms of NTAP, the morphological and physico-chemical damages in bacterial cells were analyzed. NTAP was effective for the surface decontamination of all products tested and, especially, of cut apple, where the microbial populations were reduced between 1.3 and 1.8 log units for the two Salmonella strains and E. coli O157: H7, respectively, after 15 min of exposure. In the rest of foods, no significant differences in the lethality obtained for the E. coli O157:H7 strain were observed, with inactivation rates of between 0.6 and 0.9 log cycles after a 15-min treatment. On the other hand, the strains from the rest of pathogenic microorganisms studied were extremely resistant on tofu, where barely 0.2–0.5 log units of inactivation were achieved after 15 min of plasma exposure. S. Enteritidis cells treated for 10 min exhibited noticeable morphological and structural changes, as observed by transmission electron microscopy, which were accompanied by a loss in membrane integrity, with an increased leakage of intracellular components and uptake of propidium iodide and marked changes in regions of their FTIR spectra indicating major alterations of the cell wall components. Overall, this indicates that loss of viability was likely caused for this microorganism by a significant damage in the cellular envelopes. However, the plasma-treated cells of L. monocytogenes did not show such obvious changes in morphology, and exhibited less marked effects on the integrity of their cytoplasmic membrane, what suggests that the death of this pathogenic microorganism upon NTAP exposure is more likely to occur as a consequence of damages in other cellular targetsSIThe authors would like to acknowledge the financial support from Junta de Castilla y León (LE077-G18

Microbiological Safety and Shelf-Life of Low-Salt Meat Products—A Review

[EN] Salt is widely employed in different foods, especially in meat products, due to its very diverse and extended functionality. However, the high intake of sodium chloride in human diet has been under consideration for the last years, because it is related to serious health problems. The meat-processing industry and research institutions are evaluating different strategies to overcome the elevated salt concentrations in products without a quality reduction. Several properties could be directly or indirectly affected by a sodium chloride decrease. Among them, microbial stability could be shifted towards pathogen growth, posing a serious public health threat. Nonetheless, the majority of the literature available focuses attention on the sensorial and technological challenges that salt reduction implies. Thereafter, the need to discuss the consequences for shelf-life and microbial safety should be considered. Hence, this review aims to merge all the available knowledge regarding salt reduction in meat products, providing an assessment on how to obtain low salt products that are sensorily accepted by the consumer, technologically feasible from the perspective of the industry, and, in particular, safe with respect to microbial stability.S

A European questionnaire-based study on population awareness and risk perception of antimicrobial resistance

Versión post-printTo tackle antimicrobial resistance (AMR) is of outmost importance for the general population to understand the severity and the relevance of different routes of transmission. Respondents of different age groups, educational and occupational backgrounds, area of living, diet and household composition participated in an online survey with questions concerning socio-demographics, personal use of antibiotics, awareness, general knowledge, sources of information, behavior and attitude toward antibiotics, and risk perception on antibiotics and AMR. Descriptive and logistic regression analyses were carried out. A total of 1252 respondents, mainly from EU, participated in the survey. About 57.7% declared they consumed antibiotics in the last year and some misguided behaviors were identified, especially for those not having a food- or health-related background, who more frequently failed in giving the right answer to uncontroversial true/false questions (ANOVA, P < 0.05). The youngest respondents were less confident on the information received from traditional media (OR = 0.425), the national government (OR = 0.462), and consumer organizations (OR = 0.497), while they frequently obtained information from social networks and online media, which could therefore be exploited as a channel for educational campaigns targeting this population group. New measures, strategies and policy agenda at a European level aimed at improving awareness on AMR among targeted community groups must be taken into consideration.S

Plasma-activated water: A cutting-edge technology driving innovation in the food industry

.Innovation regarding food production and processing is required to meet the emerging challenges of ensuring worldwide food security and meeting consumer demands for high-quality, safe and nutritious food products. This review provides insights into the current state-of-the-art of the emerging applications of Plasma Activated Water (PAW) in the food industry. PAW antimicrobial properties, inactivation mechanisms and the critical factors determining the lethal effect, as well as the bases for other technological applications are discussed. Overall, this review article describes the degree of success achieved by PAW technology in different applications and illustrates its feasibility and applicability in the food-processing industryS

The resistome of the food chain: A One Health perspective

[EN] Antimicrobial resistance (AMR) represents a significant global health problem which challenges Sustainable Development Goal 3 of the United Nations, with growing concerns about the possibility of AMR transmission through the food chain. The indiscriminate use of antimicrobials for the treatment of food production animals and for agricultural crop improvement, in addition to the direct discharge of livestock farm residues to sewage and the use of animal manure in agriculture, are among the factors that can facilitate the selec- tion and transmission of AMR throughout the food chain. The study of food microbiomes has been boosted by the advent of next- generation sequenc- ing techniques, which have enabled gaining in- depth understanding of the diversity of antimicrobial resistance genes present in food and associated en- vironments (the so- called resistome). The aim of this review is to provide an accurate and comprehensive overview of the knowledge currently available on the resistome of the most frequently consumed foods worldwide, from a One Health perspective. To this end, the different metagenomic studies which have been conducted to characterize the resistome of foods are compiled and critically discussed.Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLES

Evidence of virulence and antibiotic resistance genes from the microbiome mapping in minimally processed vegetables producing facilities

Daily consumption of fresh vegetables is highly recommended by international health organizations, because of their high content of nutrients. However, fresh vegetables might harbour several pathogenic microorganisms or contribute to spread antibiotic resistance, thus representing a hazard for consumers. In addition, little is known about the transmission routes of the residential microbiome from the food handling environment to vegetables. Therefore, we collected environmental and food samples from three manufactures producing fresh vegetables to estimate the relevance of the built environment microbiome on that of the finished products. Our results show that food contact surfaces sampled after routine cleaning and disinfection procedures host a highly diverse microbiome, including pathogens such as the enterotoxigenic Bacillus cereus sensu stricto. In addition, we provide evidence of the presence of a wide range of antibiotic resistance and virulence genes on food contact surfaces associated with multiple taxa, thus supporting the hypothesis that selection of resistant and pathogenic taxa might occur on sanitized surfaces. This study also highlights the potential of microbiome mapping routinely applied in food industries monitoring programs to ensure food safety