Edible Snail Research Articles

Therapeutic Potentials of Edible Freshwater-Snail Bellamya Bengalensis Extract against Arsenic-induced Rat Tissue Damage are Conferred by Antioxidative Mechanism and Attenuation of Pro-Inflammatory Response

Chronic arsenic exposure results in cancer. Some therapeutic agents show inadequate-potency/ side-effects in arsenic-toxicity treatment. The Bellamya bengalensis, an edible snail has long been used by rural people comprised of both ethnic and nonethnic groups as traditional medicine in several health-anomalies/ liver-disorders. In an attempt to investigate the possible protective and therapeutic effect against arsenic induced rat tissue damage are conferred by antioxidative mechanism and attenuation of pro-inflammatory response, the extract of B. bengalensis was tested in arsenic intoxicated rat model. Here, Bellamya bengalensis flesh-extract (BBE, 1 g/kg bw/day for 28days) was tested concomitantly in arsenic-intoxicated (0.6 ppm/kg bw/day for 28days) rat, in in-vitro rat liver slices (in Krebs-ringer buffer for 2 and 4 hours treatment with sodium arsenite alone or with BBE). In the rat, BBE strongly prevented arsenic-induced oxidative/necrotic damages to the intestinal epithelial tissue and liver-tissue/DNA by strengthening the antioxidant-system as shown in Non-protein soluble thiol (NPSH), Superoxide Dismutase(SOD) & catalase results which are clearly reflected in DNA-ladder/comet-assay/histo-architecture results. Arsenic alone decreased catalase and SOD activities in-vivo and in-vitro (H2O2/arsenite redox-stress to dialyzed-concentrated SOD) and also decreased antioxidative signaling molecules i.e. NPSH, serum nitric-oxide (NO) levels. At the same time, arsenic increased the tissue malondialdehyde resulting in DNA-breakage/liver-damage which except NO, were restrained by BBE that constitutes high-level of phosphorus/ascorbate/free-thiols. Moreover, an arsenic-induced increase in pro-inflammatory cytokine TNF-α was restored terminating an acute-phase-reaction. This study, for the first-time, shows the efficiencies of some organism/animal extract in hepatic and intestinal tissue challenged with a high level of arsenic with comparison to the natural level water contamination in West Bengal, India. Our present outcome may be utilized for the development of some protective/therapeutic component against arsenic toxicity from this aquatic organism. Further studies are necessary for more conclusive comments.

Fluorescence Imaging of Streptococcus pneumoniae with the Helix pomatia agglutinin (HPA) As a Potential, Rapid Diagnostic Tool.

Streptococcus pneumoniae is a common human pathogen and a major causal agent of life-threatening infections that can either be respiratory or non-respiratory. It is well known that the Helix pomatia (edible snail) agglutinin (HPA) lectin shows specificity for terminal αGalNAc residues present, among other locations, in the Forssman pentasaccharide (αGalNAc1→3βGalNAc1→3αGal1→4βGal1→4βGlc). Based on experiments involving choline-independent mutants and different growth conditions, we propose here that HPA recognizes the αGalNAc terminal residues of the cell wall teichoic and lipoteichoic acids of S. pneumoniae. In addition, experimental evidence showing that pneumococci can be specifically labeled with HPA when growing as planktonic cultures as well as in mixed biofilms of S. pneumoniae and Haemophilus influenzae has been obtained. It should be underlined that pneumococci were HPA-labeled despite of the presence of a capsule. Although some non-pneumococcal species also bind the agglutinin, HPA-binding combined with fluorescence microscopy constitutes a suitable tool for identifying S. pneumoniae and, if used in conjunction with Gram staining and/or other suitable technique like antigen detection, it may potentially facilitate a fast and accurate diagnosis of pneumococcal infections.

The Efficiency of Flotation Compared with Other Methods for Recovering Assemblages of Terrestrial and Aquatic Gastropods from Archaeological Deposits, with Reference to the Site of Pico Ramos (Basque Country, Spain)

ABSTRACTWe analysed assemblages of shells of land snails and small aquatic and wetland gastropods from a late Mesolithic-early Neolithic deposit in the cave of Pico Ramos (Basque Country). Shells were recovered by hand during excavation and all excavated deposit was processed by flotation, with a 250 μm mesh to recover floating material and a 1.0 mm mesh to recover the heavy fraction. The total assemblage comprised 5780 individuals (MNI) among 33 taxa, the sieved sub-assemblage having the highest proportions of these (2841 MNI in 31 taxa) and the hand-picked sub-assemblage the lowest (698 MNI in 11 taxa). Eleven taxa were absent from the flotation sub-assemblage, although the recovered MNI (2241; 39% of the total MNI) was high. The palaeoecological implications of the results are considered. Adult and large-sized juvenile shells of the edible land snail Cepaea nemoralis are abundant in the hand-picked sub-assemblage, but it is the absence of small-sized juvenile shells in the flotation and wet-sieved sub-assemblages that permits the inference that the species was collected for consumption. Wet sieving is therefore essential, both for interpreting hand-picked samples and in particular for the recovery of representative assemblages of land molluscs.

Structural analysis of a homogeneous polysaccharide from Achatina fulica

Edible snails have been widely used as a health food and medicine in many countries. In our study, a water-soluble polysaccharide (AF-1) was isolated and purified from Achatina fulica by papain enzymolysis, alcohol precipitation and strong anion exchange chromatography. Structureof the polysaccharide was analyzed and characterized by chemical and instrumental methods, such as Fourier transform infrared spectroscopy, high performance liquid chromatography, analysis of monosaccharide composition, methylation analysis, and nuclear magnetic resonance (NMR) spectroscopy (1H, 13C, COSY, TOCSY, NOESY, HSQC and HMBC). Chemical composition analysis indicated that AF-1 is composed of glucose (Glc) and its average molecular weight is 1710kDa. Structural analysis suggested that AF-1 is mainly consisted of a linear repeating backbone of (1→4) linked α-d-Glc p residues with one branch, α-d-Glc p, attached to the main chain by (1→6) glycosidic bonds at every five main-chain units. Further studies on biological activities of the polysaccharide are currently in progress.

Antibacterial Effect of Haemolymph Extracts of Edible Snail on Multi-drug Resistant Bacteria

Antibacterial Effect of Haemolymph Extracts of Edible Snail on Multi-drug Resistant Bacteria

Veterinary regulations for obtaining and processing edible snails

For many years Poland has been a highly recognized producer and supplier of Cornu aspersum (Cornu aspersum aspersum, Cornu aspersum maxima) and Helix pomatia snails in European markets. Exports include both live snails and snail-derived food products such as snail meat and eggs. Slime, used in pharmaceutical and cosmetic industries, is another economically significant snail-derived product. This paper presents standardized terminology for farm snails and outlines regulations concerning snail farming, trade, processing plants and snail meat obtained. The current results of microbiological studies of snail meat obtained in Poland are shown as well. The analysis conducted in this paper indicates the need to clarify legislation, especially with regard to snail farming, and to elaborate regulations on snail meat processing....

Specificity of Mechanisms of Memory Reconsolidation in Snails Trained for Rejection of Two Types of Food.

Specificity of behavioral and neuronal mechanisms of impairment of long-term memory reconsolidation was studied in edible snails trained for associative skill of rejection of two types of food: raw carrots (conditioned stimulus 1) and apple (conditioned stimulus 2). In 2 days after training, the snails received protein synthesis inhibitor cycloheximide and a reminder (conditioned stimulus 1 or 2). In 3 and 14 days after cycloheximide/reminder, we observed the absence of aversive responses to the conditioned stimulus used as the reminder and preserved responses to the conditioned stimulus not used as the reminder. Moreover, we observed specific suppression of synaptic responses of command neurons of snail defensive behavior induced by the conditioned stimulus used as the reminder after cycloheximide injection and preserved synaptic responses of neurons to the other conditioned stimulus. It was hypothesized that protein synthesis-dependent synapse-specific plasticity of command neurons can be a mechanism of selective preservation of conditioned food aversion memory in snails.

COMPARISON OF ALLERGENIC PROTEINS OF SEA SNAIL (CERITHIDEA OBTUSA) AND FRESHWATER SNAIL (POMACEA CANALICULATA)

In Malaysian and certain Asian countries, snail has high market demand and popular to the local people as food. However, snail is also frequently reported as one of the worst food allergens, dominated by severe symptoms such as asthma and anaphylactic shock. Thus, the aims of this study is to determine the allergenicity of two species of edible snails; the local sea snail, Cerithidea obtusa and the freshwater snail Pomacea canaliculata. Snail extracts were prepared from the snail flesh and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to determine their protein profiling. Allergenic proteins were detected by immunoblotting test using sera from 10 snail-allergic patients. The snails contain 31 to 34 protein fractions between 11 to >250 kDa. The prominent bands were seen at 33, 42, 74 and 250 kDa. Immunoblotting detected 15 and 16 allergenic proteins in C. obtusa and P. canaliculata, respectively. Three protein fractions at 30, 33 and 42 kDa were identified as the major allergens of C. obtusa, while six major allergens at 30, 33, 42, 74, 124 and 218 kDa were detected in P. canaliculata. Various minor allergens were also detected in both snails. This study indicated that numerous proteins of C. obtusa and P. canaliculata were allergenic. Thus, combined allergen extracts of both snails are essential to be included in diagnosis of snail allergy among local allergic patients.

Parasites of edible land snails in Edo State, Nigeria

Summary Land snails are sources of protein to man and are hosts to a number of parasites. It is imperative that the roles of the snail hosts and parasites are clearly defined. Before then however, the parasites of the different land snails collected in any locality should be identified. Land snails were collected in the wild in both dry and wet seasons. The internal organs and the faeces were examined for the presence of parasite. In the rainy season of 2015, a total of 272 snails were collected across four major towns (Benin, Uromi, Ekpoma and Auchi) in Edo State, Nigeria, while in the dry season, fewer snails (n=91) were handpicked. The snail species seen are: Achatina achatina (Linnaeus, 1758), Achatina fulica (Férussac, 1821), Acharchatina marginata (Swainson, 1982), Limicolaria aurora (Jay, 1839), L. flammea (Müller, 1774) and Limicolariopsis spp. The larvae of Strongyloides stercoralis were isolated from the various snail species with overall prevalence of 54.04 %. Snails positive with Alaria mesocercariae were L. aurora, L. flammea and Limicolariopsis spp. Additionally, few L. flammea were positive of the cercariae of Drocoelium dedriticum. Meanwhile, some samples of A. fulica harboured larvae of Angiostrongylus cantonesis, sporocysts of Fasciola gigantica and Schistosoma mansoni. Therefore, these edible snails could pose serious health hazard to man and animals by serving as a possible alternative parasite transmission route.

Effect of Praziquantel on the Tegument and Digestive Epithelium Ultrastructure of Brachylaima sp. Metacercariae Parasitizing the Edible Land Snail Cornu aspersum.

The edible land snail Cornu aspersum (Pulmonata: Stylommatophora) acts as second intermediate host in the cycle of Brachylaima sp. trematode, harboring free metacercariae in its kidney. The ingestion of undercooked infected snails by humans allows metacercariae to develop to adult stage in the intestine, causing brachylaimiasis. Praziquantel (PZQ) is the drug of choice to treat trematodiasis and it is effective against Brachylaima sp. metacercariae. The objective of this work was to assess, by transmission electron microscopy (TEM), the ultrastructural changes produced on the tegument and gastrodermis of the Brachylaima metacercariae recovered from C. aspersum treated with PZQ in comparison with untreated ones. Snails naturally infected by Brachylaima sp. metacercariae were treated by PZQ both individually and in groups. Metacercariae recovered from treated and control snails were processed for TEM. The tegument of untreated metacercariae was covered by a regular and thick glycocalyx. The syncytial epithelium contained abundant T2 secretory bodies appearing as membrane-bound biconcave disk-vesicles with high electron-dense and uniform content. The T2 secretory bodies located along the external area of the syncytium were mainly arranged at right angles to the apical plasma membrane. In treated metacercariae, the content of the T2 secretory bodies appeared altered, degenerating from high to low electron density, losing its uniform appearance and forming high electron-dense accumulations scattered around the periphery of the vesicle and separated by low electron-dense spaces. The presence of clusters was detectable in the central area. The characteristic arrangement of the T2 secretory bodies observed in untreated metacercariae was lost in treated ones. Vesicles near the apical area of the tegument no longer maintained their arrangement perpendicular to the apical plasma membrane. The characteristic arrangement of T2 secretory bodies and mitochondria was lost. The T2 secretory bodies were also found altered in the tegumental cell bodies, suggesting that the alterations started at the production stage. Mitochondria were severely degenerated and located in the apical area of the tegument. The digestive system displayed a strong contraction, which included the disappearance of the intracecal lumen.

A molecular survey of farmed and edible snails for the presence of human enteric viruses: Tracking of the possible environmental sources of microbial mollusc contamination

Snails have been grown or harvested for human consumption for centuries. Similarly to tissues or meat of other food animals, snail meat should be free from microbiological hazards including viruses. The aim of the study was to investigate the presence of human enteric viruses (hepatitis A and E virus, norovirus genogroup I, II and human adenovirus) in farmed and free-living snails intended for human consumption. In order to find the possible sources of snail contamination with viruses, the quality management system operating in the most widely-adopted snail farming system in Poland was reviewed. Additionally, the process hygiene criteria were checked through testing of snail meat and soil samples for bacterial contamination. Snails of genus Cornu and Helix were collected from two heliciculture farms and a purchase point. They were subjected to bacteriological (n = 180) and viral examination (n = 60). In the case of soil samples (n = 8) they were taken from different areas along the breeding cycle of the snails. For virus detection several real-time PCR protocols with an incorporated target-specific internal amplification control (IAC) were used. Determinations of the total aerobic bacteria count (TBC), number of Enterobacteriaceae (ENC) and enterococci (ECC) were performed using the international reference methods. Human enteric viruses were not detected in any of the tested snail samples. TBC for raw snail meat ranged from 5.1 up to 6.6 log cfu/g and ENC values did not exceed 4.8 log cfu/g. The ECC counts were below 2.0 log cfu/g. The overall microbiological status of snail meat indicated good hygiene and appropriate environmental conditions being maintained during snail breeding. TBC for soil samples was in the range of 6.0–7.7 log cfu/g indicating a low or moderate level of contamination. Only the soil samples from the plots used at the fattening stage were characterised by high ECC content increasing the risk of virus occurrence. In contrary to the sporadic finding of ECC, the ubiquitous presence of bacteria from the Enterobacteriaceae family in all types of soil samples was shown. A good microbial quality of snail meat resulted from the implemented GMP/GHP programmes and food safety management practices. This strategy appeared sufficient in reduction of microbiological risk and in prevention of virus contamination in snails. The study showed that the risk of foodborne virus infection due to consumption of snails and related products is considered negligible.

Effects of NO Donors and Inhibitors of NO Synthase and Guanylate Cyclase on the Acquisition of a Conditioned Defense Food Aversion Response in Edible Snails.

Experiments on edible snails revealed that NO synthase blockade with a nonspecific neuronal NO synthase inhibitor L-NAME before defense food aversion conditioning is followed by a decrease in the rate of learning. Exogenous NO donors, sodium nitroprusside and dinitrosyl iron complex, were shown to improve learning. Chronic administration of a specific soluble guanylate cyclase inhibitor ODQ also increased the rate of learning. Our results indicate that NO has a modulatory effect on the formation of a conditioned response in this type of learning.

Levels of Some Heavy Metals in African Giant Land Snail (<i>Archachatina marginata</i>) in Major Markets in Abeokuta, South West Nigeria

The level of heavy metals (Pb, Cu, Cd) as bio indicator of metal pollution in Abeokuta by analysing snails samples from major markets in Abeokuta. The level of heavy metals (Pb, Cu, Cd) were determined using Atomic absorption Spectrophotometer. Analysis of the results showed that the concentration of lead ranged from 4.15 mg/kg in Omida market to 7.93mg/kg in Lafenwa market. Similarly, Copper concentration ranged from 0.339mg/kg in Omida market to 0.719 mg/kg in Lafenwa market. The highest concentration of Cadmium was at Lafenwa market with a value of 0.06 mg/kg. Lafenwa market showed the highest concentration of the three metals and the trend of metal concentration was of the order Pb > Cu > Cd. The levels of contamination of the snail samples were lower than the recommended FAO/WHO levels. However, there is need for regular periodic checking of heavy metals level of edible snails available in open market to safe guard the health of the general public.

Encystment/excystment response and serotypic variation in the gastropod parasite Tetrahymena rostrata (Ciliophora, Tetrahymenidae)

Tetrahymena rostrata, which is characterized by a particular encystment-excystment cycle involving autogamy, has been recently found infecting the kidney of edible Helix aspersa snails under farming conditions. In this work, the effects of several factors on its encystment/excystment behaviour and the occurrence of different serotypes were investigated. The encystment/excystment response under starvation conditions was seriously affected by temperature. While a peak of encystment at 48 h followed by a progressive spontaneous excystment was observed at 18 and 25 °C, the encystment response was practically inhibited at 5 °C and clearly slowed down at 10 °C. At 30 °C, most of surviving ciliates remained encysted throughout the experiment, with spontaneous excystment being detected only after switching the temperature to 18 °C. Soil components also affected the encystment/excystment behaviour at 18 °C, with spontaneous excystment occurring in the presence of a sterile-filtered soil extract or mineral water but being strongly minimized with a non-filtered soil extract. Resting cysts formed in the latter extract exhibited a 3–4 times thicker and ultrastructurally more complex wall than that formed in mineral water and retained the excystment ability for about 4 weeks. Incomplete desiccation did not affect significantly the encystment response, while the mucus and kidney extracts from snails as well as a ciliate extract strongly stimulated a rapid excystment. Finally, two different serotypes infecting H. aspersa in heliciculture farms of Galicia (NW Spain) were identified, but no differences were observed between the encystment/excystment responses exhibited by two isolates belonging to each serotype.

Determination and characterization of vitamin B12 compounds in edible sea snails, ivory shell Babylonia japonica and turban shell Turdo Batillus cornutus

In this study, we characterized and quantified vitamin B12 compounds in popular edible snails Babylonia japonica and Turdo Batillus cornutus using a microbiological assay based on Lactobacillus delbrueckii subsp. lactis ATCC 7830. The meat and viscera of B. japonica contained 27.2 ± 9.1 and 92.8 ± 25.8 μg of vitamin B12 per 100 g, respectively. However, the meat and viscera of T. cornutus contained extremely low amounts of vitamin B12 (3.0 ± 1.5 and 15.1 ± 8.3 μg of vitamin B12 per 100 g, respectively). We identified the vitamin B12 compounds from the edible portions (meat and viscera) of B. japonica and T. cornutus using liquid chromatography–electrospray ionization/tandem mass spectrometry. We found that B. japonica contained substantial amounts of true vitamin B12, while pseudovitamin B12 was the predominant corrinoid in T. cornutus. These results indicate that the meat and viscera of B. japonica are excellent sources of vitamin B12 for humans.

Praziquantel efficacy against Brachylaima sp. metacercariae (Trematoda: Brachylaimidae) parasitizing the edible landsnail Cornu aspersum and its HPLC-MS/MS residue determination

Cornu aspersum is a terrestrial edible snail, often parasitized by Brachylaima (Trematoda) metacercariae. Ingestion of undercooked snails by humans allows metacercariae to develop to adult in the intestine causing brachylaimiasis (expected mortality rate 5–10%). The cosmopolitan character of the trematode and of its vector, enhanced in a future climate change scenario, and the absence of adequate sanitary controls of the snails in marketplaces clearly increase the risk of human brachylaimiasis. The treatment of farmed snails with praziquatel (PZQ) would be a tool to control this food-borne disease. The objectives of this study were: to report the prevalence of Brachylaima metacercariae parasitizing C. aspersum in marketplaces, to assess the efficacy and tolerance of PZQ in C. aspersum and to develop an HPLC-MS/MS analytical method to quantify PZQ residue in the edible snail (the acceptable daily intake of PZQ is 0.17 mg/kg bw in humans). Prevalence of parasitization of C. aspersum by Brachylaima metacercariae in public marketplaces reached the 80%. PZQ was orally administered to snails, mixed with the usual snail food. In dose determination assays three doses were individually tested (10 days): 1.2 mg PZQ/snail, 1.8 mg PZQ/snail (efficacy 97.3%, p < 0.001) and 2.4 mg PZQ/snail (efficacy 98.7%, p < 0.001). In dose confirmation tests (n = 200) the 2.4 mg PZQ/snail dose was group tested (10 snails/box, 7 days): 2 g of PZQ supplemented snail food were disposed daily in the treatment group boxes and 2 g of snail food (placebo) in the control boxes (efficacy 94.6%, p < 0.001; prevalence dropped from 68.7% in control group to 10.1% in treatment group, p < 0.001). Received dose was 220.2 mg PZQ/kg snail with shell. In the analytical method, linearity, lower limit of quantification (0.05 μg/ml), selectivity, carry over, accuracy, precision, dilution integrity, matrix effect and stability were tested. Sixty snails were treated (11 mg PZQ/g snail food) and analyzed. PZQ was detected and quantified (0.093 mg PZQ/g snail). PZQ treatment of C. aspersum is effective, well tolerated by the snail, affordable and easy to reproduce in snail farms.

Reproductive cycle and oviposition in Zidona dufresnei (Caenogastropoda: Volutidae) from northern Patagonia, Argentina

This study describes the reproductive cycle in the edible marine snail Zidona dufresnei in San Antonio Bay (Patagonia, Argentina), an unusual population that inhabits shallow waters. Histological techniques together with monthly field observations over a two-year period were used to describe the gametogenic cycle, the season of oviposition and the presence of egg capsules. Females were mature from August to April and there was proliferation of the germinal epithelium immediately after evacuation. Growth and resorption of oocytes were observed throughout the study period. Males were reproductively active throughout the year. The histological analysis is consistent with the observations in nature, in which females were recorded depositing egg capsules from late August to late April. The reproductive period seems to be closely related to water temperature and photoperiod. The relatively high seawater temperature in San Antonio Bay may be one of the relevant factors that contributes to the extended period of oviposition and gamete evacuation in Z. dufresnei.

Lectin-histochemical assessment of carbohydrate determinants in tumour cells of main histological types of gastric cancer

Aim. 69 cases of gastric cancer were investigated, among them 31 cases of diffuse type, 25 cases of intestinal and 13 mixed-type, using lectins of eight specificities: wheat germ, peanut, edible snail, common elder, laburnum tree, soybeans, lentils and mistletoe.Methods and results. Maximum frequency of the high lectin binding was found in the diffuse type for common elder (72.4%), edible snail and soybean lectins (67.7% each). Intestinal type of the gastric cancer was characterized by high rate of tumor cell binding to peanut lectins (52%) and wheat germ lectins (48%). In mixed type – with lectins of peanut and soybeans (53.8% each). Meanwhile lectins exhibiting high binding frequency are characterized by a more intensive binding in comparison with the normal mucosa in the same case. Cases of vascular invasion with tumour cells and without it were compared. In the intestinal type of the gastric cancer the maximum degree of staining difference was with edible snail and common elder lectins with the predominance in the group with invasion (26.4% and 20.2%, respectively). In the diffuse type of the gastric cancer, the highest frequency of intense binding was in the group with invasion with common elder (68%), edible snail (63%), laburnum tree (61.5%), and lentils lectins (57.8%). In the mixed type of the stomach cancer an intensive staining in the presence of vascular invasion was with peanut, soybean (53.8% each) and wheat germs lectins (42.2%).

Determination of fatty acids of phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol and phosphatidylserine from the cephalopedal and total body of edible snail Helix lucorum

Objective: The objective of the study was to examine the nutritive value of Helix lucorum meat and to create awareness about fatty acid composition of phospholipid subclasses of the total body and cephalopedal tissues of the snail. Methods: Thin layer chromatography plates contained lipid samples placed in the chromatography tank containing: chloroform/ethanol/water/triethylamine. The phospholipid subclasses were dissolved in about 5 ml of methanol and 5 drop of sulfuric acid. The mixture was refluxed for 2 h to form fatty acid methyl esters at 85 °C. Fatty acids were detected by Gas chromatography. Results: The most noteworthy result was the high level of C20:2ω6 in PE (10.49%-11.35%) and PC (17.33%-12.96%). Appreciable quantity of essential fatty acid C18:2ω6 was determined in PC (20.85%-17.46%) and PE (16.88%-17.53%) from both tissues. Precursor of eicosanoids, C20:4ω6 was found apparently high in PI, PS and PE of the total body. The highest level of ΣPUFA was 63.90% in PE from total body whereas the highest level of ΣSFA was 60.79% in PI from the cephalopedal. ΣMUFA level was pretty low in PI, PS and PE. Conclusion: The study is a guide for biochemical and nutritional value of edible snails and can be useful for further investigation on physiological and systematic studies of other species.

A Refinement of an International Standard Method (ISO/TS 15216–2:2013) to Allow Extraction and Concentration of Human Enteric Viruses from Tissues of Edible Snail Species

In the recent years, a revival in interest in snail meat consumption has promoted a rapid development of snail farming systems to cover an increasing consumer demand and to protect the free-living snail population. Snail meat, like other types of food intended for human consumption, should be free from any microbiological hazards before being placed on the market. Snail meat may contain bacteria, but little is known about the possibility of contamination with human enteric viruses. Therefore, to test snail tissues for viruses, a suitable virus detection method is needed. Up to now, many methods for virus extraction and concentration from molluscan shellfish have been published, but only one has been adopted as an international standard procedure. In this study, a refinement of an ISO method (ISO/TS 15216–2:2013) was conducted to make it suitable for processing of edible snail tissues. The digestive glands from three edible snail species (Helix pomatia, Cornu aspersum maxima, Cornu aspersum aspersum) were used as samples, and method performance was assessed on the basis of murine norovirus RNA detection in spiked samples using a one-step real-time reverse transcription-PCR. The mean percentage of virus recovery from tissues of C. a. maxima was 5.71 %, 0.31 % for C. a. aspersum and 1.28 % for edible snail. As demonstrated here, this method was successfully applied for virus detection in snail samples, and its use can be recommended in monitoring of snails for virus contamination.