Sea Food quality and safety
Molecular Typing of Vibrio parahaemolyticus Strains Isolated from Mollusks in the North Adriatic Sea
Autori: Rahman M.S., Carraro R., Cardazzo B., Carraro L., Meneguolo D.B., Martino M.E., Andreani N.A., Bordin P., Mioni R., Barco L., Novelli E., Balzan S., Fasolato L. (2017)
Riferimenti: Foodborne Pathogens and Disease, 14 (8), pp. 454-464. DOI: 10.1089/fpd.2016.2263
Summary: Background:Vibrio parahaemolyticus is an emerging foodborne pathogen in the Mediterranean, usually associated with shellfish consumption. The increase in the number of outbreaks in Europe is primarily associated with the global warming of the ocean that has a great impact on the spread and genetic selection of waterborne pathogens. The primary role of Italy in Europe's mollusk production, together with the fact that cases of infections with V. parahaemolyticus are not always notified to the European community, highlighted the necessity of acquiring new information about the epidemiological involvement of shellfish products.
Objective: The aim of the study was to provide useful insights into the first steps of the Risk Assessment associated with V. parahaemolyticus through the molecular characterization of isolates from commercialized mollusks.
Materials and Methods: A total of 102 strains identified as V. parahaemolyticus were investigated as part of a larger sampling (1-year survey) from several shellfish species collected from the Venice lagoon and the North Adriatic sea. All strains were characterized by multilocus sequence typing and tested for the presence of virulence genes (trh and tdh). The study of sampling/environmental factors and epidemiological analyses was performed to describe the behaviors of the different genetic populations.
Results: The population structure analysis highlighted three genetic clusters that could be subject to temperature selection during cold (≤15°C) and warm (>16°C) seasons. Moreover, other factors, such as molluscan species (clams/mussels), probably played a role in the distribution of genetic clusters. Although few strains carried the virulence factors (n = 6 trh+), epidemiological links with clinical isolates and a local dissemination of some sequence types were underlined.
Conclusion: This work provides a useful background on the genotype spread as a first step in the Hazard Identification in light of future climate changes.
Link: https://www.liebertpub.com/doi/abs/10.1089/fpd.2016.2263
Using a concentrate of phenols obtained from olive vegetation water to preserve chilled food: Two case studies
Autori: Fasolato L., Cardazzo B., Balzan S., Carraro L., Andreani N. A., Taticchi A., Novelli E.
Riferimenti: ITALIAN JOURNAL OF FOOD SAFETY, vol. 5, p. 81-85, ISSN: 2239-7132, doi: 10.4081/ijfs.2016.5651
Summary: Phenols are plant metabolites characterised by several interesting bioactive properties such as antioxidant and bactericidal activities. In this study the application of a phenols concentrate (PC) from olive vegetation water to two different fresh products – gilt-head seabream (Sparus aurata) and chicken breast – was described. Products were treated in a bath of PC (22 g/L; chicken breast) or sprayed with two different solutions (L1:0.75 and L2:1.5 mg/mL; seabream) and then stored under refrigeration conditions. The shelf life was monitored through microbiological analyses – quality index method for seabream and a specific sensory index for raw breast. The secondary products of lipid-peroxidation of the chicken breast were determined using the thiobarbituric acid reactive substances (TBARs) test on cooked samples. Multivariate statistical techniques were adopted to investigate the impact of phenols and microbiological data were fitted by DMfit software. In seabream, the levels of PC did not highlight any significant difference on microbiological and sensory features. DMfit models suggested an effect only on H2S producing bacteria with an increased lag phase compared to the control samples (C: 87 h vs L2: 136 h). The results on chicken breast showed that the PC bath clearly modified the growth of Pseudomonas and Enterobacteriaceae. The phenol dipping was effective in limiting lipid-peroxidation (TBARs) after cooking. Treated samples disclosed an increase of shelf life of 2 days. These could be considered as preliminary findings suggesting the use of this concentrate as preservative in some fresh products.
Link: https://www.pagepressjournals.org/index.php/ijfs/article/view/5651
Occurrence and molecular characterisation of Vibrio parahaemolyticus in crustaceans commercialised in Venice area, Italy
Autori: Caburlotto G., Suffredini E., Toson M., Fasolato L., Antonetti P., Zambon M., Manfrin A.
Riferimenti: INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY, vol. 220, ISSN: 0168-1605, doi:10.1016/j.ijfoodmicro.2015.12.007
Summary: Infections due to the pathogenic human vibrios, Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus, are mainly associated with consumption of raw or partially cooked bivalve molluscs. At present, little is known about the presence of Vibrio species in crustaceans and the risk of vibriosis associated with the consumption of these products. The aim of the present study was to evaluate the prevalence and concentration of the main pathogenic Vibrio spp. in samples of crustaceans (n = 143) commonly eaten in Italy, taking into account the effects of different variables such as crustacean species, storage conditions and geographic origin. Subsequently, the potential pathogenicity of V. parahaemolyticus strains isolated from crustaceans (n = 88) was investigated, considering the classic virulence factors (tdh and trh genes) and four genes coding for relevant proteins of the type III secretion systems 2 (T3SS2α and T3SS2β). In this study, the presence of V. cholerae and V. vulnificus was never detected, whereas 40 samples (28%) were positive for V. parahaemolyticus with an overall prevalence of 41% in refrigerated products and 8% in frozen products. The highest prevalence and average contamination levels were detected in Crangon crangon (prevalence 58% and median value 3400 MPN/g) and in products from the northern Adriatic Sea (35%), with the samples from the northern Venetian Lagoon reaching a median value of 1375 MPN/g. While genetic analysis confirmed absence of the tdh gene, three of the isolates contained the trh gene and, simultaneously, the T3SS2β genes. Moreover three possibly clonal tdh-negative/trh-negative isolates carried the T3SS2α apparatus. The detection of both T3SS2α and T3SS2β apparatuses in V. parahaemolyticus strains isolated from crustaceans emphasised the importance of considering new genetic markers associated with virulence besides the classical factors. Moreover this study represents the first report dealing with Vibrio spp. in crustaceans in Italy, and it may provide useful information for the development of sanitary surveillance plans to prevent the risk of vibriosis in seafood consumers.
Link: https://www.sciencedirect.com/science/article/pii/S0168160515301872?via%3Dihub
Minimum bactericidal concentration of phenols extracted from oil vegetation water on spoilers, starters and food-borne bacteria
Autori: Fasolato, L., Cardazzo, B., Balzan, S., Carraro, L., Taticchi, A., Montemurro, F., Novelli, E.
Riferimenti: Italian Journal of Food Safety, 2015 May 28; 4 (2): 4519
Summary: The aim of the study was to assess the in vitro effect of phenols extracted from oil vegetation water (PEOW) on several food-borne strains. Antibacterial activity of PEOW was based on the minimum bactericidal concentration (MBC) on microtitre assay. The taxa tested were: Staphylococcus (n. 5), Listeria (n. 4), Escherichia (n. 2), Salmonella (n. 1), Pseudomonas (n. 3), Lactobacillus (n. 2) and Pediococcus (n. 1). S. aureus and L. monocytogens showed the lowest level of resistance to PEOW (MBC=1.5-3 mg/mL). In contrast, the Gram negative strains (e.g. S. Typhimurium and Pseudomonas spp.) were in some cases unaffected by the tested doses and the MBCs ranged between 6 to 12 mg/mL. Starter cultures were dramatically reduced on growth (e.g. Staphylococcus xylosus; 0.75 mg/mL MBC). The thresholds for pathogenic strains could be considered for further applications of PEOW in food models (e.g. shelf life or challenge test studies).
Understanding the association of Escherichia coli with diverse macroalgae in the lagoon of Venice
Autori: Quero, G. M; Fasolato, L.; Vignaroli, C.; Luna, G. M.
Riferimenti: Scientific Reports volume 5, Article number: 10969 (2015)
Summary: Recent studies provided evidence that the macroalga Cladopohora in lakes hosts associated Escherichia coli, with consequences on the environmental and human health. We expanded these investigations to other macroalgae (Ulva spp., Sargassum muticum and Undaria pinnatifida) widespread in the lagoon of Venice (Italy). Attached E. coli were abundant, accounting up to 3,250 CFU gram−1 of alga. Macroalgal-associated isolates belonged to all E. coli phylogroups, including pathogenic ones, and to Escherichia cryptic clades. Attached E. coli showed potential to grow even at in situ temperature on macroalgal extracts as only source of carbon and nutrients, and ability to produce biofilm in vitro. The genotypic diversity of the attached isolates was high, with significant differences between algae and the overlying water. Our evidences suggest that attached populations consist of both resident and transient strains, likely resulting from the heterogeneous input of fecal bacteria from the city. We report that cosmopolitan and invasive macroalgae may serve as source of E. coli, including pathogenic genotypes, and that this habitat can potentially support their growth. Considering the global diffusion of the macroalgae here studied, this phenomenon is likely occurring in other coastal cities worldwide and deserves further investigations from either the sanitary and ecological perspectives.
Data Fusion for Food Authentication: Fresh/Frozen–Thawed Discrimination in West African Goatfish (Pseudupeneus prayensis) Fillets
Autori: Ottavian M.; Fasolato L.; Serva L; Facco P.; Barolo M.
Riferimenti: Food and Bioprocess Technology April 2014, Volume 7, Issue 4, pp 1025–1036
Summary: The substitution of fresh fish with frozen–thawed fish is a typical fraud that not only damages consumers from an economical point of view, but also causes safety issues. Furthermore, fish authentication is important for correct product labeling, as promoted by recent regulatory actions. In this paper, we present the results of the authentication of fresh west African goatfish (Pseudupeneus prayensis) fillets using different analytical technologies, namely a portable visible/near-infrared spectrometer, a compact digital camera, and a texture analyzer. First, the classification performance of the abovementioned analytical technologies is evaluated and compared. Then, it is shown how the fusion of different technologies can be effectively used to improve the classification accuracy. Particularly, spectra and color features extracted from digital images returned a classification accuracy of 100 and 98.5 %, respectively, when considered separately. However, the classification accuracy fell to 80 % when considering measurements taken with a 24-h delay. Data fusion, instead, allowed a classification accuracy of 100 % also after 24 h. Hence, the combination of a spectrometer and a digital camera is very promising for cost-effective on-line/at-line applications, as both sensors are rapid, non-invasive, and do not require sample preparation. Furthermore, since more than 200 samples were collected over a prolonged period of time (1 year), the classification models encompassed some sources of variability (seasonality effects and size) that are not usually accounted for in similar studies.
Link: https://link.springer.com/article/10.1007/s11947-013-1157-x
Vibrio Trends in the Ecology of the Venice Lagoon
Autori: M. S. Rahman;M. E. Martino;B. Cardazzo;P. Facco;P. Bordin;R. Mioni;E. Novelli;L. Fasolato
Riferimenti: Applied and Environmental Microbiology, April 2014, Volume 80 Number 8, p. 2372–2380
Summary: Vibrio is a very diverse genus that is responsible for different human and animal diseases. The accurate identification of Vibrio at the species level is important to assess the risks related to public health and diseases caused by aquatic organisms. The ecology of Vibrio spp., together with their genetic background, represents an important key for species discrimination and evolution. Thus, analyses of population structure and ecology association are necessary for reliable characterization of bacteria and to investigate whether bacterial species are going through adaptation processes. In this study, a population of Vibrionaceae was isolated from shellfish of the Venice lagoon and analyzed in depth to study its structure and distribution in the environment. A multilocus sequence analysis (MLSA) was developed on the basis of four housekeeping genes. Both molecular and biochemical approaches were used for species characterization, and the results were compared to assess the consistency of the two methods. In addition, strain ecology and the association between genetic information and environment were investigated through statistical models. The phylogenetic and population analyses achieved good species clustering, while biochemical identification was demonstrated to be imprecise. In addition, this study provided a fine-scale overview of the distribution of Vibrio spp. in the Venice lagoon, and the results highlighted a preferential association of the species toward specific ecological variables. These findings support the use of MLSA for taxonomic studies and demonstrate the need to consider environmental information to obtain broader and more accurate bacterial characterization.
Tracking the blue: A MLST approach to characterise the Pseudomonas fluorescens group
Autori: Andreani NA; Martino ME; Fasolato L.; Carraro L.; Montemurro F.; Mioni R.; Bordin P.; Cardazzo. B
Riferimenti: Food Microbiology Volume 39, May 2014, Pages 116-126
Summary: The Pseudomonas fluorescens group comprises several closely related species that are involved in food contamination and spoilage. Specifically, the interest in P. fluorescens as a spoiler of dairy products increased after the cases of “blue mozzarella” that occurred in Italy in 2010.
A Multilocus Sequence Typing (MLST) scheme was developed and applied to characterise 136 isolates (reference strains and food borne isolates) at strain level, to reveal the genetic relationships among them and to disclose any possible genetic clustering of phenotypic markers involved in food spoilage (protease, lipase, lecithinase activities and pigmented or fluorescent molecule production). The production of dark blue diffusible pigment was evaluated on several bacterial culture media and directly on mozzarella cheese.
The MLST scheme provided precise genotyping at the strain level, and the population analyses of the concatenated sequences allowed major taxa to be defined. This approach was revealed to be suitable for tracking the strains according to their origin, such as dairy plants or food matrices. The genetic analysis revealed the presence of a connection between the blue pigment production and a specific phylogenetic cluster. The development of the online database specific to the P. fluorescens group (http://pubmlst.org/pfluorescens) will facilitate the application of the scheme and the sharing of the data.
Link: https://www.sciencedirect.com/science/article/pii/S0740002013002335?via%3Dihub
Molecular Typing of Vibrio parahaemolyticus Strains Isolated from Mollusks in the North Adriatic Sea
Autori: Rahman M.S., Carraro R., Cardazzo B., Carraro L., Meneguolo D.B., Martino M.E., Andreani N.A., Bordin P., Mioni R., Barco L., Novelli E., Balzan S., Fasolato L.
Riferimenti: Foodborne Pathogens and Disease, 14 (8), pp. 454-464. DOI: 10.1089/fpd.2016.2263
Summary: Background:Vibrio parahaemolyticus is an emerging foodborne pathogen in the Mediterranean, usually associated with shellfish consumption. The increase in the number of outbreaks in Europe is primarily associated with the global warming of the ocean that has a great impact on the spread and genetic selection of waterborne pathogens. The primary role of Italy in Europe's mollusk production, together with the fact that cases of infections with V. parahaemolyticus are not always notified to the European community, highlighted the necessity of acquiring new information about the epidemiological involvement of shellfish products.
Objective: The aim of the study was to provide useful insights into the first steps of the Risk Assessment associated with V. parahaemolyticus through the molecular characterization of isolates from commercialized mollusks.
Materials and Methods: A total of 102 strains identified as V. parahaemolyticus were investigated as part of a larger sampling (1-year survey) from several shellfish species collected from the Venice lagoon and the North Adriatic sea. All strains were characterized by multilocus sequence typing and tested for the presence of virulence genes (trh and tdh). The study of sampling/environmental factors and epidemiological analyses was performed to describe the behaviors of the different genetic populations.
Results: The population structure analysis highlighted three genetic clusters that could be subject to temperature selection during cold (≤15°C) and warm (>16°C) seasons. Moreover, other factors, such as molluscan species (clams/mussels), probably played a role in the distribution of genetic clusters. Although few strains carried the virulence factors (n = 6 trh+), epidemiological links with clinical isolates and a local dissemination of some sequence types were underlined.
Conclusion: This work provides a useful background on the genotype spread as a first step in the Hazard Identification in light of future climate changes.
Link: https://www.liebertpub.com/doi/abs/10.1089/fpd.2016.2263
Molecular Typing of Vibrio parahaemolyticus Strains Isolated from Mollusks in the North Adriatic Sea
Autori: Rahman M.S., Carraro R., Cardazzo B., Carraro L., Meneguolo D.B., Martino M.E., Andreani N.A., Bordin P., Mioni R., Barco L., Novelli E., Balzan S., Fasolato L.
Riferimenti: Foodborne Pathogens and Disease, 14 (8), pp. 454-464. DOI: 10.1089/fpd.2016.2263
Summary: Background:Vibrio parahaemolyticus is an emerging foodborne pathogen in the Mediterranean, usually associated with shellfish consumption. The increase in the number of outbreaks in Europe is primarily associated with the global warming of the ocean that has a great impact on the spread and genetic selection of waterborne pathogens. The primary role of Italy in Europe's mollusk production, together with the fact that cases of infections with V. parahaemolyticus are not always notified to the European community, highlighted the necessity of acquiring new information about the epidemiological involvement of shellfish products.
Objective: The aim of the study was to provide useful insights into the first steps of the Risk Assessment associated with V. parahaemolyticus through the molecular characterization of isolates from commercialized mollusks.
Materials and Methods: A total of 102 strains identified as V. parahaemolyticus were investigated as part of a larger sampling (1-year survey) from several shellfish species collected from the Venice lagoon and the North Adriatic sea. All strains were characterized by multilocus sequence typing and tested for the presence of virulence genes (trh and tdh). The study of sampling/environmental factors and epidemiological analyses was performed to describe the behaviors of the different genetic populations.
Results: The population structure analysis highlighted three genetic clusters that could be subject to temperature selection during cold (≤15°C) and warm (>16°C) seasons. Moreover, other factors, such as molluscan species (clams/mussels), probably played a role in the distribution of genetic clusters. Although few strains carried the virulence factors (n = 6 trh+), epidemiological links with clinical isolates and a local dissemination of some sequence types were underlined.
Conclusion: This work provides a useful background on the genotype spread as a first step in the Hazard Identification in light of future climate changes.
Link: https://www.liebertpub.com/doi/abs/10.1089/fpd.2016.2263
Using a concentrate of phenols obtained from olive vegetation water to preserve chilled food: Two case studies
Autori: Fasolato L., Cardazzo B., Balzan S., Carraro L., Andreani N. A., Taticchi A., Novelli E.
Riferimenti: ITALIAN JOURNAL OF FOOD SAFETY, vol. 5, p. 81-85, ISSN: 2239-7132, doi: 10.4081/ijfs.2016.5651
Summary: Phenols are plant metabolites characterised by several interesting bioactive properties such as antioxidant and bactericidal activities. In this study the application of a phenols concentrate (PC) from olive vegetation water to two different fresh products – gilt-head seabream (Sparus aurata) and chicken breast – was described. Products were treated in a bath of PC (22 g/L; chicken breast) or sprayed with two different solutions (L1:0.75 and L2:1.5 mg/mL; seabream) and then stored under refrigeration conditions. The shelf life was monitored through microbiological analyses – quality index method for seabream and a specific sensory index for raw breast. The secondary products of lipid-peroxidation of the chicken breast were determined using the thiobarbituric acid reactive substances (TBARs) test on cooked samples. Multivariate statistical techniques were adopted to investigate the impact of phenols and microbiological data were fitted by DMfit software. In seabream, the levels of PC did not highlight any significant difference on microbiological and sensory features. DMfit models suggested an effect only on H2S producing bacteria with an increased lag phase compared to the control samples (C: 87 h vs L2: 136 h). The results on chicken breast showed that the PC bath clearly modified the growth of Pseudomonas and Enterobacteriaceae. The phenol dipping was effective in limiting lipid-peroxidation (TBARs) after cooking. Treated samples disclosed an increase of shelf life of 2 days. These could be considered as preliminary findings suggesting the use of this concentrate as preservative in some fresh products.
Link: https://www.pagepressjournals.org/index.php/ijfs/article/view/5651
Tracing seafood at high spatial resolution using NGS-generated data and machine learning: Comparing microbiome versus SNPs
Autori: Milan M, Maroso F, Dalla Rovere G, Carraro L, Ferraresso S, Patarnello T, Bargelloni L, Cardazzo B, Fariselli P.
Riferimenti: Food Chemistry. Volume 286, 15 July 2019, Pages 413-420
Summary: Developing reliable tools to trace food origin represents a major goal for producers and control authorities. Here, we test the hypothesis whether NGS-generated data could provide a reliable tool to ensure seafood traceability. As a test case, we used the Manila clam Ruditapes philippinarum, a bivalve mollusk of high commercial interest with worldwide distribution, collected in the Venice lagoon sites subjected to prohibition of clam harvesting because of chemical contamination as well as in authorized clam harvesting areas. The results obtained demonstrated that the geographic origin of Manila clam may be more accurately determined basing on microbiome data than single nucleotide polymorphisms. In particular, combining microbiome data with machine-learning techniques, we provide the experimental evidence that it is possible to trace the clam place of origin at high spatial resolution. Considering its low cost and portability, NGS-analysis of microbiome data might represent a cost-effective, high-resolution tool for reliable food traceability.
Link: https://www.sciencedirect.com/science/article/pii/S0308814619303516
