HLA-DQ typing in the diagnostic algorithm of celiac disease.

Objective: celiac disease (CD) is an immune-mediated chronic inflammatory disease associated with HLA-DQ2 and DQ8 molecules. We evaluated the role of HLA in the CD diagnostic algorithm in order to contribute to the development of practical indications for the use of HLA typing. Material and methods: we selected 317 subjects typed for DR-DQ genes. CD was present in 123 patients, and 89 were included in the study; a control sample of 70 healthy individuals was recruited. Results: 64% of patients with CD carried DQ2 heterodimer (α5β2), 13.5% carried DQ8 heterodimer without DQ2, 21.4% only showed β2 chain and 1.1% were positive for DQ2 α5 chain. The only presence of α5 chain did not predispose to CD, while DQB1*02 allele resulted more frequent than in other reports, pointing out the intrinsic correlation between β2 chain and CD. In the case-control study we observed a progression of increased risk, ranging from 1:7 for HLA-DQ2 homozygous to 1:85 for DQ8 heterozygous subjects. Overall, 8,6% of first degree family members were affected, exclusively in presence of HLA-DQ2, -DQ8 or DQB1*02, and CD was significantly more frequent among siblings than parents. Finally, considering the different patterns of clinical presentation among the HLA-DQ risk classes identified we found no relationship between CD clinical presentation and HLA-DQ risk categories. Conclusions: our results strengthen the evidence that HLA-DQ status strongly influences the development of CD and demonstrate that knowledge of a patient's HLA-DQ genotype allows to establish clinically relevant genetic risk profiles

Food safety considerations in relation to Anisakis pegreffii in anchovies (Engraulis encrasicolus) and sardines (Sardina pilchardus) fished off the Ligurian Coast (Cinque Terre National Park, NW Mediterranean)

Aims: The purpose of this work was to verify whether E. coli is a good indicator of viral contamination in mussels and Adenovirus could represent a better alternative as indicator organism of viral presence to guarantee consumer health protection. Methods and Results: Eighty samples of mussels from La Spezia Gulf were analysed for E. coli, Salmonella, Adenovirus, Norovirus and hepatitis A virus with cultural and biomolecular tests. The results of bacterial parameters showed E. coli within the law’s limits and the absence of Salmonella. Twelve samples were positive for Adenovirus presence, one for Norovirus genogroup II and two for hepatitis A virus. None of these positive mussels was found to be contaminated with more than one virus at the same time. Conclusion: This study showed that there was not a direct correlation between the presence of human pathogenic viruses and bacterial indicators. Significance and Impact of the Study: Both E. coli and Adenovirus cannot be considered valid substitutes for the direct research of human pathogenic viruses in mussels. To improve consumer health protection, the European Commission will provide standardized methods for Norovirus and hepatitis A virus detection as soon as possible

HEAT TREATMENT FOR THE PRECOOCKED SHRIMPS PRODUCTION: VIBRIO PARAHAEMOLYTICUS RISK ANALYSIS

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Detection and Characterization of Histamine-Producing Strains of Photobacterium damselae subsp. damselae Isolated from Mullets

Photobacterium damselae subsp. damselae (Pdd) is considered to be an emerging pathogen of marine fish and has also been implicated in cases of histamine food poisoning. In this study, eight strains isolated from mullets of the genera Mugil and Liza captured in the Ligurian Sea were characterized, and a method to detect histamine-producing Pdd from fish samples was developed. The histamine-producing potential of the strains was evaluated in culture media (TSB+) using a histamine biosensor. Subsequently, two strains were used to contaminate mackerel fillets (4 or 40 CFU/g), simulating a cross-contamination on the selling fish stalls. Sample homogenates were enriched in TSB+. The cultures were then inoculated on thiosulfate-citrate-bile salts-sucrose agar (TCBS) and the dark green colonies were cultured on Niven agar. The violet isolates were characterized using specific biochemical and PCR based tests. All Pdd strains were histamine producers, yielding concentration varying from 167 and 8977 µg/mL in TSB+ cultures incubated at 30 °C for 24 h. Pdd colonies were detected from the inoculated mackerel samples and their histidine decarboxylase gene was amplified using species-specific primer pairs designed for this study. The results indicate that mullets can be source of Pdd and the fish retailers needs to evaluate the risk posed by cross-contamination on the selling fish stalls

Sensibilità di Campylobacter jejuni al nitrito di sodio nell’impasto di salsiccia fresca.

Sono stati contaminati con una concentrazione nota (105 ufc/g) di Campylobacter jejuni (ATCC n. 29428) dei campioni di impasto di salsiccia, addizionati con nitrito di sodio, alle concentrazioni di 100 e 150 ppm per verificare l’effetto inibente dell’additivo nei confronti del microrganismo. La sopravvivenza di quest’ultimo, nel tempo, in presenza e in assenza del sale, è stata valutata conservando il prodotto alle temperature di refrigerazione (4°C), di cantina (12°C) ed ambiente (20°C): per ciascuna temperatura sono stati esaminati cinque campioni. Il microrganismo è risultato in grado di sopravvivere nell’impasto di salsiccia, in tutte le condizioni ambientali considerate, in assenza di nitrito di sodio. L’addizione del sale all’impasto, inoltre, è risultato efficace nei confronti di C. jejuni già al dosaggio di 100 ppm (temperatura di cantina e temperatura ambiente). In tutte le prove, comunque, si è potuto osservare che l’aggiunta di 150 ppm di nitrito di sodio, specialmente nell’arco delle prime 48 ore, ha influito negativamente sulla sopravvivenza di C. jejuni in modo più evidente rispetto all’impiego di 100 ppm del sale