Is your salad safe to eat?

Ready-to-eat (RTE) leafy vegetables or mixed-ingredient salads are a popular part of the modern healthy diet. Contamination of these products with bacterial pathogens can occur during any step in the production chain and, since there is no step that kills pathogens during the production of RTE salads, a completely safe final product can never be guaranteed. In fact, almost 10% of RTE mixed-ingredient salads from Swedish retail outlets tested in this thesis were contaminated with foodborne pathogens or presumptive pathogens. Listeria monocytogenes was isolated from two out of 141 samples analysed. The other findings included detection of virulence genes present in pathogenic Yersinia enterocolitica and shiga toxin-producing Escherichia coli (STEC), but these could not be culturally confirmed. In growth trials, it was found that mixing RTE baby spinach with cooked chicken (representing a mixed-ingredient salad) strongly influenced growth of inoculated L. monocytogenes, pathogenic Y. enterocolitica and E. coli O157:H7 gfp+ during storage under temperature abuse (15 °C). Mixed-ingredient salad also supported growth of L. monocytogenes under storage conditions recommended for this product in Sweden (8 °C for three days). The estimated risk of listeriosis was 16-fold higher on consuming a mixed-ingredient salad stored at 8 °C at the end of shelf-life, or 200 000-fold higher when the salad was stored at 15 °C, compared with consumption on the day of inoculation. Hence, preventing temperature abuse during storage is of critical importance in mitigating the risk of foodborne listeriosis from these mixed-ingredient salads. The microbiota of RTE baby spinach and mixed-ingredient salad during the growth trials was studied by Illumina 16S rRNA amplicon sequencing. This molecular method revealed changes in the bacterial communities during storage at 8 or 15 °C and correlations were observed between viable counts of inoculated strains and abundances of some taxonomic orders. However, this method was not useful in identifying human pathogens in the salads, even when these were present in high numbers that can cause disease in humans

Food safety risk perceptions and mitigation techniques in the dumpster diving community in Sweden

An online questionnaire was used to investigate behaviors and habits relating to food retrieval by Swedish dumpster divers. Respondents were also asked to share information on their background, reasons for engaging in dumpster diving, and perceptions of potential bacterial hazards associated with the consumption of dis-carded foods. The questionnaire was mainly distributed to Swedish social media groups focusing on dumpster diving, and a total of 92 responses were received. The most common reason given for engaging in dumpster diving was to reduce food waste and associated negative environmental impacts (60%, n = 55). Many of the respondents (65%) had completed university education, and around three-quarters (73%) had some form of employment or were enrolled in studies. Half the respondents (52%, n = 48) perceived a risk of falling ill after consuming food obtained through dumpster diving, but very few (2%) reported they had been made ill by food they had picked up from dumpsters. Around one-fifth (22%) of the respondents did not know of any bac-teria that could cause foodborne infections or food poisoning. Salmonella was mentioned by 35% of the respon-dents, while Listeria was mentioned by 18%. The respondents reported employing various techniques to reduce the risk of encountering harmful microbiological agents, for example, rinsing their food retrievals or discarding food that appeared spoiled. These are novel findings on dumpster divers' perceptions of perceived health risks and the strategies they use to mitigate such risks with food obtained through dumpster diving

Den livsmedelshygieniska kvaliteten hos franska opastöriserade dessertostar

This study was performed to investigate the bacteriological quality of French cheeses made from raw milk. Fifty cheeses of this type were purchased from Swedish retail premises. The methods described by the Nordic Committee on Food Analysis (NMKL) were used to determine the number of Enterobacteriaceae, presumptive Escherichia coli, coagulase positive staphylococci and Listeria monocytogenes. In 32 cheeses (64%) the number of bacteria mentioned above exceeded the determined maximum value. Thirty samples (60%) showed high counts of Enterobacteriaceae. In seven samples (14%), a potentially hazardous amount of presumptive E. coli was found. Coagulase positive staphylococci were detected only in two samples while L. monocytogenes was not detected in any of the 50 raw milk cheeses. A logistic regression analysis suggested that cheeses with a high pH-value had an average higher content of analyzed bacteria than cheeses with a lower pH (p=0,033).Femtio franska opastöriserade dessertostar köptes i svenska butiker och analyserades enligt NMKL-metoderna avseende Enterobacteriaceae, presumtiva Escherichia coli, koagulaspositiva stafylokocker och Listeria monocytogenes. Då alla analysparametrar sammanställts bedömdes 32 av de 50 analyserade ostarna (64%) som otjänliga. 30 ostar (60%) innehöll ett för högt antal Enterobacteriaceae. Innehållet av presumtiva E. coli var för högt i sju ostar (14%). Dessa bedömdes som otjänliga och fyra stycken (8%) bedömdes som tjänliga med anmärkning avseende presumtiva E. coli. Två ostar (4%) bedömdes som otjänliga avseende koagulaspositiva stafylokocker. L. monocytogenes kunde inte påvisas i någon av de analyserade ostarna. Enligt en logistisk regressionsanalys löpte en ost med ett högre pH en statistiskt signifikant större risk att bedömas som otjänlig (p=0,033) än en ost med ett lägre pH

Is your lunch salad safe to eat? Occurrence of bacterial pathogens and potential for pathogen growth in pre-packed ready-to-eat mixed-ingredient salads

As part of a trend toward healthy convenience foods, ready-to-eat (RTE) mixed-ingredient salads have become popular products among consumers. A mixed-ingredient salad contains combinations of raw (e.g. leafy vegetables and tomatoes) and processed (e.g. chicken, salmon, ham, pasta and couscous) ingredients. Contamination of leafy vegetables can occur during any step in the production chain and, since there is no step that kills pathogens, a completely safe final product can never be guaranteed. Meat ingredients, for example poultry meat and ham, are generally heat-treated before preparation, but may be contaminated after this treatment, e.g. when diced or sliced. When several ingredients are mixed together, cross-contamination may occur. Preparation of mixed-ingredient salads requires human handling, which presents an additional risk of bacterial contamination. With high-protein ingredients, e.g. cooked meat, the mixed-ingredient salad represents an excellent substrate for bacterial growth. This article reviews current knowledge regarding human bacterial pathogen prevalence in mixed-ingredient salads and the potential for pathogen growth in this product during storage

Food safety risk perceptions and mitigation techniques in the dumpster diving community in Sweden

An online questionnaire was used to investigate behaviors and habits relating to food retrieval by Swedish dumpster divers. Respondents were also asked to share information on their background, reasons for engaging in dumpster diving, and perceptions of potential bacterial hazards associated with the consumption of discarded foods. The questionnaire was mainly distributed to Swedish social media groups focusing on dumpster diving, and a total of 92 responses were received. The most common reason given for engaging in dumpster diving was to reduce food waste and associated negative environmental impacts (60%, n = 55). Many of the respondents (65%) had completed university education, and around three-quarters (73%) had some form of employment or were enrolled in studies. Half the respondents (52%, n = 48) perceived a risk of falling ill after consuming food obtained through dumpster diving, but very few (2%) reported they had been made ill by food they had picked up from dumpsters. Around one-fifth (22%) of the respondents did not know of any bacteria that could cause foodborne infections or food poisoning. Salmonella was mentioned by 35% of the respondents, while Listeria was mentioned by 18%. The respondents reported employing various techniques to reduce the risk of encountering harmful microbiological agents, for example, rinsing their food retrievals or discarding food that appeared spoiled. These are novel findings on dumpster divers’ perceptions of perceived health risks and the strategies they use to mitigate such risks with food obtained through dumpster diving

Food safety challenges and One Health within Europe

This review discusses food safety aspects of importance from a One Health perspective, focusing on Europe. Using examples of food pathogen/food commodity combinations, spread of antimicrobial resistance in the food web and the risk of transmission of zoonotic pathogens in a circular system, it demonstrates how different perspectives are interconnected. The chosen examples all show the complexity of the food system and the necessity of using a One Health approach. Food safety resources should be allocated where they contribute most One Health benefits. Data on occurrence and disease burden and knowledge of source attribution are crucial in assessing costs and benefits of control measures. Future achievements in food safety, public health and welfare will largely be based on how well politicians, researchers, industry, national agencies and other stakeholders manage to collaborate using the One Health approach. It can be concluded that closer cooperation between different disciplines is necessary to avoid silo thinking when addressing important food safety challenges. The importance of this is often mentioned, but more proof of concept is needed by the research community

Water supply delivery failures-a scenario-based approach to assess economic losses and risk reduction options

Access to a reliable water supply is central for a well-functioning society. However, water supply systems are subject to a wide range of threats which may affect their ability to provide water to society. This paper presents a novel risk assessment approach that enables thorough analyses of economic losses and associated uncertainties under a range of water supply disruption scenarios. The purpose is to avoid sub-optimization when prioritizing between risk reduction measures, by integrating the full range of possible outcomes from low to high probability events. By combining risk analysis with cost-benefit analysis, additional information is provided on measures for leveraging investments in managing and reducing the risks. This enables the identification of the most economically profitable risk reduction alternatives and enables decision makers to build strategic capacity for operating in difficult and uncertain futures. The presented approach is exemplified on the island of Gotland, one of the most water scarce areas of Sweden. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Funding details: Svenska ForskningsrÃ¥det Formas, 942-2015-130; Funding text 1: This research was funded by the European Union's Horizon 2020 research and innovation program under the Marie Sk?odowska-Curie grant agreement No 754412; Region V?stra G?taland; and the Swedish Research Council Formas contract no 942-2015-130. This research was performed within the DRICKS center for drinking water research coordinated by the Chalmers University of Technology. The authors would like to thank Mikael Tiouls and Lars Westerlund, as well as all other workshop participants, at Region Gotland for contributing with Gotland-specific expertise on scenarios and societal effects.</p

Microbial communities and Food safety aspects of crickets (Acheta domestica) reared under controlled conditions

In an approach combining microbiological culture methods with high-throughput sequencing, this study investigated the microbial communities (bacteria, moulds and yeasts) in Swedish-produced edible crickets (Acheta domesticus) reared in a controlled environment. The effects of different feeds on microbial loads and populations in crickets were also studied. The crickets used were third-generation offspring from wild-caught individuals from Sweden, which are adapted to grow in a laboratory environment. The efficiency of rinsing to decrease microbial load was evaluated not obtaining a significant decrease of plating counts for total aerobic counts (TAC) and Enterobacteriaceae. Crickets were divided into three batches and fed different diets (control feed, early-cut red clover hay (ECH), late-cut fresh red clover (LCF)) for 62 days. Bacterial numbers (TAC and Enterobacteriaceae) on whole raw crickets ranged between 7 and 8 log cfu/g. Pre-rinsing in water did not reduce these levels (P=0.19). All batches tested negative for the food-borne bacteria Salmonella, Listeria monocytogenes, Bacillus cereus and Clostridium perfringens. The mean mould count for crickets fed control feed was 2.8 log cfu/g, while the values for crickets fed ECH and LCF were 4.2 and 4.5 log cfu/g, respectively. The dominant bacterial communities were Proteobacteria, Bacteroidetes and Firmicutes, with Firmicutes and Proteobacteria dominating in crickets fed control feed, Firmicutes dominating in crickets fed LCF and Proteobacteria dominating in crickets fed ECH. Aspergillus flavus, a fungus that is capable of producing mycotoxins, was detected in control feed and ECH reared crickets. More work is needed to identify specific food-borne pathogens in edible crickets and establish possible bacterial quality reference values, as an important step in developing microbial quality and safety parameters to ensure consumer safety