Entomological Investigation of the Main Entomatic Adversities for Terrestrial Gastropods Helix aspersa Müller (Mollusca Gastropoda Pulmonata): A Preliminary Study in Sardinian Heliciculture Farms.

In the years 2020-2022, a survey was carried out with the aim of controlling the entomofauna present in seven Sardinian snail farms. The sampling was carried out during the spring-summer and autumn-winter periods, corresponding to the production cycles of the Helix aspersa snails (Müller, 1774), the species most frequently bred in snail farms. The samples were taken from farms located in different areas of the region. For the predatory species found in most of the farms, 38% of the individuals were of the Silpha tristis Illiger, 1798 (Coleoptera: Silphidae) species, 32% were Ocypus olens Müller, 1764 (Coleoptera: Staphylinidae), and 24% were Carabus (Macrothorax) morbillosus constantinus Kraatz, 1899 (Coleoptera: Carabidae). The Lampyris sardiniae Geisthardt, 1987 (Coleoptera: Lampyridae) and Licinus punctatulus Fabricius, 1792 (Coleoptera: Carabidae) species were equally detected in 3% of the farms. In some farms, the predatory species S. tristis and C.morbillosus costantinus had caused the death of several snails. This preliminary study aimed to provide a first evaluation and description of the critical issues facing the snails present in seven Sardinian snail farms. First, a specific survey of the entomofauna during two observational periods (i.e., the spring-summer and autumn-winter periods) was conducted. Context-specific description and evaluation will allow providing valid information for Italian and European heliciculture farms to ensure the well-being of the mollusks. The presence of predatory species in snail farms is not easy to control, but some precautions could be useful to avoid massive colonization.

Evaluation of the microbiological and chemical aspects of autochthonous wild snails in Sardinia.

This study was conducted to acquire knowledge on the epidemiology and ecology of some zoonotic agents in snails. Chemical and microbiological analysis was carried out on 46 samples of snails belonging to the species of Helix aspersa and Helix (Eobania) vermiculata. The association between heavy metals and wild snails, a native consumer product in the Region of Sardinia, was determined. The molecular characterisation of Listeria monocytogenes virulence genes has shown a genetic profile that deserves more attention for the improvement of surveillance and risk prevention. Specimens of H. vermiculata showed higher concentrations of cadmium (M=0.80±0.56 mg/kg) than H. aspersa (M=0.61±0.17 mg /kg). A further objective was to determine whether the samples showed significant differences from the point of view of secretion characterisation, in terms of protein content, and to identify species-specific correlations and possible relationships with the environment. The presence of Salmonella enterica sub.sp houtenae (6,14: z4, z23) and Salmonella enterica subsp diarizonae (47: k: e, n, z15) (1 sample), Listeria monocytogenes (2 samples) with Molecular characterization of virulence genes together with the measurement of heavy metals in samples of wild snails has shown a health and hygiene profile that would deserve greater attention for the improvement of the surveillance and prevention of microbiological and chemical risk in such products which currently show a tendency towards increase in consumption.

Microbiological Findings in Ready-to-Eat and Precooked Food Distributed in Public Catering Halls in Cagliari Province, Italy.

During this research 159 samples of ready-to-eat and precooked food were examined for the detection of Salmonella spp., Listeria monocytogenes, Escherichia coli, coagulase-positive staphylococci and Enterobacteriaceae, bacterial count. All samples were negative for Salmonella spp. and Listeria monocytogenes; although a low count of coagulase-positive staphylococci (no. 5 samples) and E. coli (no. 3) was found. We proceeded with the identification of the isolates on every sample with high, moderate and low-count of Enterobacteriaceae, to better understand the microbial ecology. The Enterobacteriaceae species most frequently detected were Pantoea spp. (29.62%), Enterobacter cloacae (20.37%) and Serratia liquefaciens (12.96%); other different species of Enterobacteriaceae were detected with a <10% presence. Since there are no legal regulations indicating tolerance or limit values or this kind of microorganisms related to the samples, it would be appropriate, in the presence of high count of Enterobacteriaceae or by type of ready-to-eat and precooked food, to proceed with the identification of every microorganism.

Microbiological and Chemical Evaluation of Helix Spp. Snails from Local and Non-EU Markets, Utilised as Food in Sardinia.

With this study, 28 pools of snails of the genus Helix, respectively Helix aspersa (n=24) and Helix vermiculata (n=4) were analysed. They were taken from snail farming and stores. The snails were from Sardinia, other regions of Italy, and from abroad. All the samples were examined as pool looking for these microbiological target: Salmonella spp., Listeria monocytogenes, Escherichia coli O157, Clostridium perfringens, Norovirus and Hepatitis A Virus (HAV). In the same pools, the concentration of cadmium and lead by inductively coupled plasma mass spectrometry was also determined. The levels of these heavy metals were quite high, especially for cadmium. Two samples were positive for Salmonella spp., while no sample was positive for Escherichia coli O157, HAV and Norovirus. Two samples were positive for Clostridium perfringens and 8 for Listeria monocytogenes. The microrganisms related to Listeria monocytogenes were identified using biochemical techniques, then serotyped and gene sequenced by multiple loci sequence typing technique. Furthermore, antimicrobial restistence was tested on the same samples.