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- Cassi, Xavier Fernandez, et al.
(author)
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Microbial communities and Food safety aspects of crickets (Acheta domestica) reared under controlled conditions
- 2020
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In: Journal of insects as food and feed. - 2352-4588. ; 6, s. 429-440
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Cassi, Xavier Fernandez, et al.
(author)
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The house cricket (Acheta domesticus) as a novel food: a risk profile
- 2019
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In: Journal of insects as food and feed. - 2352-4588. ; 5, s. 137-157
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Research review (peer-reviewed)abstract
- Novel foods represent sustainable alternatives to traditional farming and conventional foodstuffs. The house cricket (Acheta domesticus) is considered as one of the most promising reared insects due to their attractive nutritional profile and lower feed conversion ratio compared to other animals. However, putative health hazards associated with consumption of crickets have previously not been investigated. The present study assesses the risks of A. domesticus reared in closed systems controlled by the implementation of hazard analysis and critical control points and good farming practices. Due to the novelty of the topic, data scarcity has been a limiting factor, hence comparative evidence from closely related species belonging to the order Orthoptera (e.g. grasshoppers, locusts, and other cricket species) have been included. The present risk profile identified as main hazards: (1) high total counts of aerobic bacteria; (2) presence of spore-forming bacteria post thermal processing; (3) accumulation of cadmium and other heavy metals; and (4) a possible increase of allergenic reactions due to exposure to insects and insect derived products. Important data gaps regarding edible crickets and their safety as novel foods have been highlighted in the future perspective section, representing aims for future research. Identified data gaps include: (1) farming conditions of the insects being studied; (2) data on the impact of thermal processing of the products prior to consumption; (3) fungal communities and mycotoxins-producing fungi in reared crickets; and (4) heavy metals not fully assessed (chromium, aluminium and arsenic) and other chemical hazards produced during processing (i.e. heterocyclic aromatic amines, acrylamide). The present risk profile explores food safety risks related to consumption of A. domesticus, thereby constituting an example of chemical and microbial hazards risk profiling on edible insects, covering rearing to consumption.
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| 3. |
- Fernandez-Cassi, Xavier, et al.
(author)
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Novel foods: a risk profile for the house cricket (Acheta domesticus)
- 2018
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In: EFSA Journal. - : Wiley. - 1831-4732. ; 16
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Journal article (peer-reviewed)abstract
- Novel foods could represent a sustainable alternative to traditional farming and conventional foodstuffs. Starting in 2018, Regulation (EU) 2283/2015 entered into force, laying down provisions for the approval of novel foods in Europe, including insects. This Approved Regulation establishes the requirements that enable Food Business Operators to bring new foods into the EU market, while ensuring high levels of food safety for European consumers. The present risk profile tackles the hazards for one of the most promising novel food insects, the house cricket (Achetadomesticus). The risk profile envisages a closed A.domesticus crickets rearing system, under Hazard Analysis and Critical Control Points (HACCP) and good farming practices (GFP), in contrast with open cricket farms. The methodology used involves screening the literature and identifying possible hazards, followed by adding relevant inclusion criteria for the evidence obtained. These criteria include animal health and food safety aspects, for the entire lifespan of crickets, based on the farm to fork One Health principle. When data were scarce, comparative evidence from close relatives of the Orthoptera genus was used (e.g. grasshoppers, locusts and other cricket species). Nevertheless, significant data gaps in animal health and food safety are present. Even if HACCP-type systems are implemented, the risk profile identifies the following considerable concerns: (1) high total aerobic bacterial counts; (2) survival of spore-forming bacteria following thermal processing; (3) allergenicity of insects and insect-derived products; and (4) the bioaccumulation of heavy metals (e.g. cadmium). Other hazards like parasites, fungi, viruses, prions, antimicrobial resistance and toxins are ranked as low risk. For some hazards, a need for additional evidence is highlighted. (c) 2018 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.
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| 4. |
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| 5. |
- Hjelmsø, Mathis Hjort, et al.
(author)
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Evaluation of Methods for the Concentration and Extraction of Viruses from Sewage in the Context of Metagenomic Sequencing.
- 2017
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:1
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Journal article (peer-reviewed)abstract
- Viral sewage metagenomics is a novel field of study used for surveillance, epidemiological studies, and evaluation of waste water treatment efficiency. In raw sewage human waste is mixed with household, industrial and drainage water, and virus particles are, therefore, only found in low concentrations. This necessitates a step of sample concentration to allow for sensitive virus detection. Additionally, viruses harbor a large diversity of both surface and genome structures, which makes universal viral genomic extraction difficult. Current studies have tackled these challenges in many different ways employing a wide range of viral concentration and extraction procedures. However, there is limited knowledge of the efficacy and inherent biases associated with these methods in respect to viral sewage metagenomics, hampering the development of this field. By the use of next generation sequencing this study aimed to evaluate the efficiency of four commonly applied viral concentrations techniques (precipitation with polyethylene glycol, organic flocculation with skim milk, monolithic adsorption filtration and glass wool filtration) and extraction methods (Nucleospin RNA XS, QIAamp Viral RNA Mini Kit, NucliSENS® miniMAG®, or PowerViral® Environmental RNA/DNA Isolation Kit) to determine the viriome in a sewage sample. We found a significant influence of concentration and extraction protocols on the detected viriome. The viral richness was largest in samples extracted with QIAamp Viral RNA Mini Kit or PowerViral® Environmental RNA/DNA Isolation Kit. Highest viral specificity were found in samples concentrated by precipitation with polyethylene glycol or extracted with Nucleospin RNA XS. Detection of viral pathogens depended on the method used. These results contribute to the understanding of method associated biases, within the field of viral sewage metagenomics, making evaluation of the current literature easier and helping with the design of future studies.
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| 6. |
- Rusiol, Marta, et al.
(author)
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Application of human and animal viral microbial source tracking tools in fresh and marine waters from five different geographical areas
- 2014
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In: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 59, s. 119-129
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Journal article (peer-reviewed)abstract
- Integrated river basin management planning to mitigate the impacts of economic, demographic and climate change is an important issue for the future protection of water resources. Identifying sources of microbial contamination via the emerging science of Microbial Source Tracking (MST) plays a key role in risk assessment and the design of remediation strategies. Following an 18-month surveillance program within the EU-FP7-funded VIROCLIME project, specific MST tools were used to assess human markers such as adenoviruses (HAdV) and JC polyomaviruses (JCPyV) and porcine and bovine markers such as porcine adenoviruses (PAdV) and bovine polyomaviruses (BPyV) via quantification with real-time PCR to analyze surface water collected from five sites within different climatic zones: the Negro River (Brazil), Glafkos River (Greece), Tisza River (Hungary), Llobregat River (Spain) and Umealven River (Sweden). The utility of the viral MST tools and the prevalence and abundance of specific human and animal viruses in the five river catchments and adjacent seawater, which is impacted by riverine contributions from the upstream catchments, were examined. In areas where no sanitation systems have been implemented, sewage can directly enter surface waters, and river water exhibited high viral loads; HAdV and JCPyV could be detected at mean concentrations of 10(5) and 10(4) Genome Copies/Liter (GC/L), respectively. In general, river water samples upstream of urban discharges presented lower human viral loads than downstream sampling sites, and those differences appeared to increase with urban populations but decrease in response to high river flow, as the elevated river water volume dilutes microbial loads. During dry seasons, river water flow decreases dramatically, and secondary effluents can represent the bulk of the riverine discharge. We also observed that ice cover that formed over the river during the winter in the studied areas in North Europe could preserve viral stability due to the low temperatures and/or the lack of solar inactivation. Porcine and bovine markers were detected where intensive livestock and agricultural activities were present; mean concentration values of 10(3) GC/L indicated that farms were sometimes unexpected and important sources of fecal contamination in water. During spring and summer, when livestock is outdoors and river flows are low, animal pollution increases due to diffuse contamination and direct voiding of feces onto the catchment surface. The field studies described here demonstrate the dynamics of fecal contamination in all catchments studied, and the data obtained is currently being used to develop dissemination models of fecal contamination in water with respect to future climate change scenarios. The results concerning human and animal targets presented in this study demonstrate the specificity and applicability Of the viral quantitative parameters developed to widely divergent geographical areas and their high interest as new indicators of human and animal fecal contamination in water and as MST tools.
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