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Anti-listerial properties of chemical constituents of Eruca sativa (rocket salad): From industrial observation to in vitro activity
Get PDFhe frequency of foodborne outbreaks epidemiologically associated with Listeria monocytogenes in fresh produce has increased in recent years. Although L. monocytogenes may be transferred from the environment to vegetables during farming, contamination of food products most commonly occurs in food processing facilities, where L. monocytogenes has the ability to establish and persist on processing equipment. The current study was undertaken to collect data on the occurrence of L. monocytogenes and the identity of the endogenous microbiota in a fresh produce processing facility, for which information has remained scarce. L. monocytogenes was not detected in the facility. Experiments simulating conditions in the processing environment were performed, including examination of bacterial growth in nutrients based on vegetables (salad juice) compared to in other types of nutrients (fish, meat). Results showed that the endogenous microbiota (dominated by Pseudomonas) grew well in iceberg lettuce and rocket salad juice at low temperatures, while growth inhibition of L. monocytogenes was observed, particularly in rocket salad juice. The anti-listerial activity in rocket salad juice was retained in a polar chromatographic fraction containing several metabolites. Characterization of this active fraction, using LC-MS/MS, led to identification of 19 compounds including nucleosides and amino acids. Further work is necessary to determine the molecular mechanism responsible for the inhibitory activity of rocket salad constituents. The study nevertheless suggests that the available nutrients, as well as a low temperature (3 ˚C) and the in-house bacterial flora, may influence the prevalence of L. monocytogenes in fresh produce processing facilities.publishedVersio
Performance of novel low trophic raw meterials in Atlantic salmon Salmo salar diets
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Consumer practices and prevalence of Campylobacter, Salmonella and norovirus in kitchens from six European countries
Get PDFAbout 40% of foodborne infections are acquired in the home. The aim of the present study was to track contamination of pathogens during domestic food preparation and link the contamination to preparation practices. Research participants from 87 households in six European countries were observed and interviewed during shopping and preparation of a chicken and vegetable meal. The presence of Salmonella spp., Campylobacter spp. and norovirus on raw chicken, kitchen surfaces, cloths and sponges was determined. The prevalence of Campylobacter on raw chicken varied from 8.3% in Norway (NO) to 80% in France (FR) and Portugal (PT), with a mean prevalence of 57%. Campylobacter was found on half of the products that had been frozen and appeared to be less prevalent on chicken from supermarkets than other sources. Salmonella was found in 8.6% of raw chicken samples, exclusively from Hungary (HU). A relationship between observed practices and spread of pathogens to kitchen surfaces was found only for the use of cutting boards for chicken and/or vegetables. After food preparation, Campylobacter and Salmonella were isolated from 23% (samples derived from HU, RO, UK) and 8.7% (HU), respectively of cutting boards. Research participants in France and Portugal were more likely to buy products that fitted their recipe, with less need for using cutting boards. Using the same board and knife for vegetables after using it for chicken and without washing with detergent was common in Portugal and Romania, but not in the other countries. Contamination with Campylobacter to other kitchen surfaces or washing utensils were found in five households (UK, RO, PT). Rinsing chicken in sinks was common in three countries (PT, HU, RO), and washing vegetables in the same sink was also usual. Prevalence of Norovirus was low, with detection in one out of 451 samples. The participants' awareness of the risk posed by pathogens from raw chicken differed among the six countries, with higher awareness in Norway and the UK than the other countries studied. In conclusion, practices intended to avoid cross-contamination from chicken to kitchen surfaces and washing utensils are not established among consumers in all European countries. Nevertheless, cross-contamination events that disseminate infectious doses of pathogens seems to be rare, probably due to the relatively low levels of pathogens in food combined with food preferences. Food safety interventions must consider the national food culture, preferences, practices and the prevalence and levels of pathogens in food. Emphasis should be on providing and promoting chicken products with lower risk (prevalence of pathogens, ready-to-cook) and safe use of cutting boards.publishedVersio
Meat analogues from a faba bean concentrate can be generated by high moisture extrusion
Get PDFThe main objective of this study was to investigate the feasibility of production of meat analogues from a faba bean protein concentrate (obtained from dry fractionation) using high-moisture extrusion (HME). The impact of the temperature, ratio between water and product feed rate and product feed rate on the physicochemical properties of the meat analogues during high-moisture extrusion (HME) was studied. The functional, textural, and sensory properties were also assessed. The impact of the moisture content was generally higher than the impact of the temperature and the feed rate within the responses evaluated. The different extrusion conditions tested did not influence the relative distribution of the oligosaccharides. Meat analogues produced with temperatures ranging between 130 and 140 °C, ratio between water and product feed rate of 4 and feed rate of 11 rpm (1.10 Kg/h) had the most positive sensory and textural properties judged by a good bite-feel (firmness) and elasticity in line with attributes associated with this product category. Of oligosaccharides analysed the content of verbascose was the highest -galacto-oligossacharide and the content of the oligosaccharides is significant higher in the extracts of the heat-treated material compared to the starting material.publishedVersio
Deposition and metabolism of dietary n-3 very-long-chain PUFA in different organs of rat, mouse and Atlantic salmon
Get PDFThere is limited knowledge about the metabolism and function of n-3 very-long-chain PUFA (n-3 VLC-PUFA) with chain lengths ≥ 24. They are known to be produced endogenously in certain tissues from EPA and DHA and not considered to originate directly from dietary sources. The aim of this study was to investigate whether n-3 VLC-PUFA from dietary sources are bio-available and deposited in tissues of rat, fish and mouse. Rats were fed diets supplemented with a natural fish oil (FO) as a source of low dietary levels of n-3 VLC-PUFA, while Atlantic salmon and mice were fed higher dietary levels of n-3 VLC-PUFA from a FO concentrate. In all experiments, n-3 VLC-PUFA incorporation in organs was investigated. We found that natural FO, due to its high EPA content, to a limited extent increased endogenous production of n-3 VLC-PUFA in brain and eye of mice with neglectable amounts of n-3 VLC-PUFA originating from diet. When higher dietary levels were given in the form of concentrate, these fatty acids were bio-available and deposited in both phospholipids and TAG fractions of all tissues studied, including skin, eye, brain, testis, liver and heart, and their distribution appeared to be tissue-dependent, but not species-specific. When dietary EPA and DHA were balanced and n-3 VLC-PUFA increased, the major n-3 VLC-PUFA from the concentrate increased significantly in the organs studied, showing that these fatty acids can be provided through diet and thereby provide a tool for functional studies of these VLC-PUFA.publishedVersio
Co-creation of a healthy dairy product with and for children
Get PDFChildren's involvement in new product development may contribute to ensure that healthy alternatives meet their wants and needs. Co-creation is a potential approach to bridge the world of the child and the grown-up product developer. In this context, the objective of the present work was to explore the potential of a co-creation approach with children to develop a healthy dairy product. A total of 52 school-aged children (54% girls, 6–13 year old) recruited from an after-school club in Montevideo (Uruguay) participated in co-creation workshops. Two sessions were carried out. In the first session, children developed a dairy product using a set of ingredients and proposed strategies to promote their product. Children showed a high level of engagement during the activity and provided actionable ideas for product development. Three key factors drove the product formulation (familiarity, hedonics, and healthiness), whereas common communication strategies were proposed by the participants to promote their products. In the second session, children evaluated four products developed by the researchers based on children’s ideas. The products showed high overall liking scores (5.9 to 7.9) despite the inclusion of novel and healthy ingredients and the lower sugar content compared to similar commercial products available in the Uruguayan marketplace. These results show the potential of involving children in the co-creation of healthy dairy products. Considering the lack of published studies regarding the use of co-creation approaches with children in the food domain, the present work provides useful insights for the implementation of co-creation to develop innovative products with and for children.acceptedVersio
Principal components analysis of descriptive sensory data: Reflections, challenges, and suggestions
Get PDFThis article presents a discussion of principal components analysis of descriptive sensory data. Focus is on standardization, many correlated variables, validation, and the use of descriptive data in preference mapping. Different ways of performing the analysis are presented and discussed with focus on how to obtain informative and reliable results. The results will be commented on in light of experience. All methods will be illustrated by calculations based on real data. The article ends with a list of suggestions for all the topics covered. Practical Application The article is about using principal components analysis (PCA) in sensory science. The applicability of the methods and ideas presented in this article are relevant for all types of descriptive sensory data. The ideas are general and comprise areas such as standardization, validation, and many correlated variables. The target group of readers for the article is the sensory scientist who uses PCA on a daily basis and who may have questions regarding how to use the method the best possible way.submittedVersio
Innovative Ultrasound-Assisted Approaches towards Reduction of Heavy Metals and Iodine in Macroalgal Biomass
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Deep neural network analysis - a paradigm shift for histological examination of health and welfare of farmed fish
Get PDFAn artificial intelligence model (AI-model) was trained for the first time to detect multi-class segmentation of skin from Atlantic salmon, using a convolutional neural network (Aiforia®). The AI-model was developed to produce reliable spatial measurements of all the successive skin layers of Atlantic salmon. The AI-model was tested on skin samples collected from eight post-smolts (produced in a research facility), with the intention of comparing skin samples from six different body sites. The results from the AI-model were highly correlated to manual measurements carried out by two experienced histologists and indicated that the abundance of epidermal and dermal skin tissues vary with body-site. The AI-model was further used to evaluate skin samples from commercially farmed Atlantic salmon. The samples were taken regularly through a production cycle (autumn 2018 to autumn 2019) and followed major operational events such as transport and de-lousing. Results from the AI-model reviled dynamic behavior of the skin, reflecting spatial changes of skin tissues related to time in the sea, life stage and operational events. Our work illustrates how unbiased datasets from histological analysis open new possibilities for comparative studies of Atlantic salmon physiology. With time, a better understanding of tissue dynamics in relation to production and diseases may arise from automated tissue analyzes.submittedVersio
An Integrated Economic Sociology Approach to Market-as-Network: The Example of a Shared Business Environment between Norway and China
Get PDFThis study applies an economic sociology perspective in exploring the importance of cultural embeddedness of firm economic activities across borders. The qualitative empirical findings of this study show that market-as-network interrelationships will become increasingly important in forming resilient business networks. The findings are data driven and uses the seafood trade and its shared business environments between Norway and China as case example. The empirical findings of this study show that market-as-network, and actor-to-actor interrelationships will become increasingly important in forming resilient business networks. It also illustrates how economic sociology can provide a holistic framework of analysis in studying cultural embeddedness.publishedVersio