High Hydrostatic Pressure Treatment of Meat Products

High hydrostatic pressure (HHP) treatment has been described to improve the microbiological safety and shelf life of ready-to-eat (RTE) meat products, as a nonthermal decontamination technology in the meat industry, applied at pre- or post-packaging. The pathogen widely studied in this product is Listeria monocytogenes that reflects the concern of the food industry. In general, microorganism’s lethality during HHP treatment depends on specific intrinsic factors of the microorganism; those factors are related to food and technological factors of treatment. In addition to processing parameters, intrinsic factors of the food matrix also exert an effect on bacteria inactivation during pressure treatment. It is known that low water activity (aw) protects microorganisms against the effects of pressure. Predictive modelling is an important tool of the novel microbial food safety management strategy that provides with accurate information to demonstrate and guarantee the safety and shelf life of the food products. The chapter describes the effect of parameters on the efficiency of this technology on meat products over pathogens, composition and the sensorial quality consequences. The predictive modelling tool is introduced for the optimisation of meat treatment

Salmonella Inactivation Model by UV-C Light Treatment in Chicken Breast

This study aims to evaluate the effectiveness of inactivating Salmonella enteritidis in fresh chicken breast by irradiation using a combination of short‑wave UV (0, 3, 6, 9, 12, and 15 J/cm2) and a natural antimicrobial such as caffeine (0, 5, 10, 15, and 20 nM/g) at 14 ◦C as alternative proposals to conventional techniques to reduce pathogens in food. The effect of temperature was studied in an initial phase (2 to 22 ◦C). The most suitable models were double Weibull in 60% of cases, with an adjustment of R2 0.9903–0.9553, and Weibull + tail in 46.67%, with an adjustment of R2 of 0.9998–0.9981. The most effective combination for the reduction in Salmonella was 12 J/cm2 of UV light and 15 nM/g of caffeine, with a reduction of 6 CFU/g and an inactivation rate of 0.72. The synergistic effect was observed by increasing caffeine and UV light. Furthermore, the physico‑chemical characteristics of the food matrix were not affected by the combination of both technologies. Therefore, these results suggest that this combination can be used in the food industry to effectively inactivate Salmonella enteritidis without deteriorating product quality

Unveiling fresh-cut lettuce processing in argentine industries: evaluating Salmonella levels using predictive microbiology models

A survey was performed to gather information on the processing steps, conditions, and practices employed by industries processing ready-to-eat (RTE) leafy vegetables in Argentina. A total of seven industries participated in the survey. A cluster analysis of the data obtained was performed to identify homogeneous groups among the participating industries. The data collected were used as inputs of two predictive microbiology models to estimate Salmonella concentrations after chlorine washing, during storage and distribution of final products, and to rank the different practices according to the final estimated Salmonella levels. Six different clusters were identified by evaluating the parameters, methods, and controls applied in each processing step, evidencing a great variability among industries. The disinfectant agent applied by all participating industries was sodium hypochlorite, though concentrations and application times differed among industries from 50 to 200 ppm for 30 to 110 s. Simulations using predictive models indicated that the reductions in Salmonella in RTE leafy vegetables would vary in the range of 1.70–2.95 log CFU/g during chlorine-washing depending on chlorine concentrations applied, washing times, and vegetable cutting size, which varied from 9 to 16 cm2 among industries. Moreover, Salmonella would be able to grow in RTE leafy vegetables during storage and distribution, achieving levels of up to 2 log CFU/g, considering the storage and transportation temperatures and times reported by the industries, which vary from 4 to 14 °C and from 18 to 30 h. These results could be used to prioritize risk-based sampling programs by Food Official Control or determine more adequate process parameters to mitigate Salmonella in RTE leafy vegetables. Additionally, the information gathered in this study is useful for microbiological risk assessments

Modelling of the Behaviour of Salmonella enterica serovar Reading on Commercial Fresh-Cut Iceberg Lettuce Stored at Different Temperatures

The aim of this study was to model the growth and survival behaviour of Salmonella Reading and endogenous lactic acid bacteria on fresh pre-cut iceberg lettuce stored under modified atmosphere packaging for 10 days at different temperatures (4, 8 and 15 °C). The Baranyi and Weibull models were satisfactorily fitted to describe microbial growth and survival behaviour, respectively. Results indicated that lactic acid bacteria (LAB) could grow at all storage temperatures, while S. Reading grew only at 15 °C. Specific growth rate values (μmax) for LAB ranged between 0.080 and 0.168 h−1 corresponding to the temperatures 4 and 15 °C while for S. Reading at 15 °C, μmax = 0.056 h−1. This result was compared with published predictive microbiology models for other Salmonella serovars in leafy greens, revealing that predictions from specific models could be valid for such a temperature, provided they were developed specifically in lettuce regardless of the type of serovars inoculated. The parameter delta obtained from the Weibull model for the pathogen was found to be 16.03 and 18.81 for 4 and 8 °C, respectively, indicating that the pathogen underwent larger reduction levels at lower temperatures (2.8 log10 decrease at 4 °C). These data suggest that this Salmonella serovar is especially sensitive to low temperatures, under the assayed conditions, while showcasing that a correct refrigeration could be an effective measure to control microbial risk in commercial packaged lettuce. Finally, the microbiological data and models from this study will be useful to consider more specifically the behaviour of S. Reading during transport and storage of fresh-cut lettuce, elucidating the contribution of this serovar to the risk by Salmonella in leafy green products

Risk Factors Influencing Microbial Contamination in Food Service Centers

An improvement of food service centers in recent years has been made based on the implementation of the principles of the Hazard Analysis and Critical Control Points (HACCP) system. Food safety preventive measures have been focused on training of handlers in hygiene practices and on improving the sanitary quality of meals. In Europe, an increasing trend in foodborne outbreaks has been attributed to catering businesses. This fact highlights that the impact of preventive measures in the past few years has not been sufficiently effective as expected. Special attention should be paid to food services destined to susceptible population, such as hospitals, long-term care facilities, or school canteens, because people could be more susceptible to become ill when exposed to foodborne agents. There are numerous relevant factors influencing microbial contamination of foods, according to the preparation method, hygienic sanitary conditions of catering facilities, or food handling, storage, and distribution. In the present chapter, a review of the most significant risk factors influencing microbial contamination of foods in food service centers are described with special focus on those establishments where susceptible population (i.e., children, elderly, immunocompromised people) is present. Besides, potential preventive measures to be considered in that establishments and correct implementation of food safety actions are given to provide useful recommendations to food handlers, food operators, and risk managers

Modelling the growth of Listeria monocytogenes in Mediterranean fish species from aquaculture production

Over the last couple of decades, several studies have evaluated growth dynamics of L. monocytogenes in lightly processed and ready-to-eat (RTE) fishery products mostly consumed in Nordic European countries. Other fish species from aquaculture production are of special interest since their relevant consumption patterns and added value in Mediterranean countries, such as sea bream and sea bass. In the present study, the growth of L. monocytogenes was evaluated in fish-based juice (FBJ) by means of optical density (OD) measurements in a temperature range 2–20 °C under different atmosphere conditions (i.e. reduced oxygen and aerobic). The Baranyi and Roberts model was used to estimate the maximum growth rate (μmax) from the observed growth curves. The effect of storage temperature on μmax was modelled using the Ratkowsky square root model. The developed models were validated using experimental growth data for L. monocytogenes in sea bream and sea bass fillets stored under static and dynamic temperature conditions. Overall, models developed in FBJ provided fail-safe predictions for L. monocytogenes growth. For the model generated under reduced oxygen conditions, bias and accuracy factor for growth rate predictions were 1.15 and 1.25, respectively, showing good performance to adequately predict L. monocytogenes growth in Mediterranean fish products. The present study provides validated predictive models for L. monocytogenes growth in Mediterranean fish species to be used in microbial risk assessment and shelf-life studies

EGF regulates survivin stability through the Raf-1/ERK pathway in insulin-secreting pancreatic β-cells

<p>Abstract</p> <p>Background</p> <p>Postnatal expansion of the pancreatic β-cell mass is required to maintain glucose homeostasis immediately after birth. This β-cell expansion is regulated by multiple growth factors, including glucose, insulin, insulin-like growth factor (IGF-1) and epidermal growth factor (EGF). These mitogens signal through several downstream pathways (AKT, ERK, STAT3, and JNK) to regulate the survival and proliferation of β-cells. Survivin, an oncofetal protein with both pro-proliferative and anti-apoptotic properties, is a known transcriptional target of both IGF-1 and EGF in cancer cells. Here, we analyzed the effects of the β-cell mitogens IGF-1 and EGF on survivin regulation in the established pancreatic β-cell model cell lines, MIN6 and INS-1 and in primary mouse islets.</p> <p>Results</p> <p>In pancreatic β-cells, treatment with glucose, insulin, or EGF increased survivin protein levels at early time points. By contrast, no significant effects on survivin were observed following IGF-1 treatment. EGF-stimulated increases in survivin protein were abrogated in the presence of downstream inhibitors of the Raf-1/MEK/ERK pathway. EGF had no significant effect on <it>survivin </it>transcription however it prolonged the half-life of the survivin protein and stabilized survivin protein levels by inhibiting surviving ubiquitination.</p> <p>Conclusions</p> <p>This study defines a novel mechanism of survivin regulation by EGF through the Raf-1/MEK/ERK pathway in pancreatic β-cells, via prolongation of survivin protein half-life and inhibition of the ubiquitin-mediated proteasomal degradation pathway. This mechanism may be important for regulating β-cell expansion after birth.</p

‘MicroHibro’: A software tool for predictive microbiology and microbial risk assessment in foods

A tool able to quantitatively assess the fate of potential pathogenic microorganisms in foods along the food chain and their impact on public health is highly valuable for food safety decision-makers. The aim of this work was to present an overview of the Predictive Microbiology software MicroHibro, which is able to assess the evolution of potential pathogens and spoilage microorganisms along the food chain, providing estimates for the exposure level and risk associated with a food product. The application is built on an extensive Predictive Microbiology Model Data Base (PMDB) including kinetic processes like growth, inactivation, transfer as well as dose-response models. PMDB can be populated with new models by using an on-line tool in combination with a standardized method for describing Predictive Microbiology models. This enables MicroHibro to be easily updated, increasing its applicability and use. Estimation of microbial risk associated with a food product can be achieved, in MicroHibro, by describing steps in any food chain using four different microbial processes (growth, inactivation, transfer and partitioning). As a result, an estimate of the concentration and prevalence of microorganisms in the food of interest as well as attendant risk are provided. Also, MicroHibro allows comparing different predictive models and validate them by introducing user's data. In this paper, examples are provided to illustrate how predictive models can be incorporated in MicroHibro, and then, used to develop a Quantitative Microbial Risk Assessment model. The use of expert computational systems is a powerful tool for supporting food safety and quality activities by Health Authorities and the food industry. They represent a breakthrough in the assessment and management of food safety based on scientific evidence

Improve and application of a new methodologic tool adapted to the European Higher Education Area applied in Degree in Food Science and Technology (CYTA), in Forest Engineering (GIFOR) and in Veterinary

La masificación en las aulas de las universidades plantea grandes retos en el desarrollo de la enseñanza según el modelo del Espacio Europeo de Enseñanza Superior (EEES). El presente trabajo desarrolló una herramienta metodológica (Píldoras Informativas) para potenciar la implicación del alumnado en el aprendizaje autónomo, basado en la creación y edición de videos por parte del alumnado, guiada, orientada y evaluada por el profesor mediante las Guías Director. Se ha llevado a cabo la introducción de las píldoras informativas en las sesiones expositivas de asignaturas de grados impartidos en la Universidad de Córdoba, incluyendo asignaturas inmersas en itinerario de inglés. Con los resultados obtenidos se plantea la creación de seminarios de difusión de la metodología para profesorado en formación.The overcrowding in the classrooms of the universities poses great challenges in the development of the teaching according to the model of the European Space of Higher Education (EHEA). The present work developed a methodological tool (Informative Pills) to enhance the involvement of students in autonomous learning, based on the creation and editing of videos by the students, guided and evaluated by the teacher through the Director Guides. The introduction of the informative pills has been carried out in the expositive sessions of subjects taught at the University of Córdoba, including subjects immersed in the English language. With the results obtained, it is proposed the creation of seminars to disseminate the methodology for teaching staff in training. Keywords: Information pills, short videos, active student participation