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Despite its commercial value, the shelf-life of the Atlantic mackerel (Scomber scombrus) during refrigerated storage was poorly investigated. In this regard, the Quality Index Method (QIM) was proposed as a suitable scoring system for freshness and quality sensorial estimation of fishery products. This study aims to develop a deterministic mathematical model based on dynamic temperatures conditions and a suc-cessive statistical analysis of the results obtained. This model will be exploited to predict the shelf-life of the Atlantic mackerel based on specific storage temperatures. A total of 60 fresh fishes were subdivided into two groups and respectively stored in ice for 12 days at a constant temperature of 1±0.5°C (Group A) and a fluctuating temperature ranging between 1 and 7°C (Group B). Microbiological analysis and sensory evaluation through the QIM were performed on each fish at regular time inter-vals. A critical value of 6 Log cfu/g of spoilage bacteria (mainly psychotropic) associated with a significant decay of the sensorial characteristics was exceeded after 9 days of storage for Group A and 3 days for Group B. A reliable prediction of fish freshness was obtained by modelling the QIM as a function of the spoilage bacteria behaviour. A coefficient β of correlation was determined to convert the spoilage bacteria load into a Quality Index score. The adoption of mathematical predictive models to assess microbial behaviour under different environmental conditions is an interest-ing tool for food industries to maximize production and reduce waste.

It is widely accepted that human is exposed to microplastics through food consumption, however data occurrence in foodstuffs are still little and basically limited to seafood. In this study, the presence of microplastics was investigated in icefish (Neosalanx spp.) samples sourced from various mass-market retailers in Italy, supplied as frozen, glazed and vacuum-packed product. Icefish is a small freshwater fish widely imported in Europe from China as surrogate of other fish species subjected to commercial restriction, consumed whole after cooking in several culinary preparation. The samples (~10 g of icefish from each of the 40 packs tested) were digested using a solution of 10% potassium hydroxide and filtered through a 5 μm pore-size filter. Filters of the samples were observed under a stereomicroscope and the chemical composition of the items detected were analysed by FTIR spectroscopy. A total of 163 items were counted in 37 (92.5%) samples with a mean value of 0.42±0.28 items/g w.w. Fibers were the most detected morphotype and several plastic polymers, such as polypropylene, polyethylene, polyethylene terephthalate and polystyrene, were identified by FT-IR analysis. As store-bought samples, the sources of microplastics could be substantially related to contamination during food processing. However, an intravital exposure to microplastics present in the surroundings waters cannot be ruled out. More foodstuffs need to be investigated for microplastic presence. In this study, microplastic occurrence was reported in freshwater biota intended for human consumption sampled directly from supermarket contributing to the risk assessment of human exposure to microplastics via food consumption.

Background. Hyperostosis is a productive change characterized by an increase of the periosteal ossification combined to resorption of the bony tissue. It is common in several fish species. Its presence has been reported in the silver scabbardfish, Lepidopus caudatus (Euphrasen, 1788). The aim of the presently reported study is to improve the knowledge on the presence of hyperostotic pterygiophores in L. caudatus. Materials and methods. In total, 50 specimens of Lepidopus caudatus, captured off the coast of Messina (Sicily, Italy) were examined by radiography. Deformed pterygiophores were decalcified and processed for histopathological examination, and the sections obtained were stained with haematoxylin and eosin. Results. Forty (80%) of the 50 specimens examined showed skeletal deformities exclusively on the pterygiophores of the dorsal fin. In total, 433 deformities were observed. Histological examination showed slight expansion of the bone tissue, which was poor in cells and characterised by thin layers of compact bone tissue. Macroscopic, radiographic, and histological findings were consistent with diagnosis of hyperostosis. Conclusion. Hyperostosis of L. caudatus does not affect its consumption. However, it may be a complication for filleting techniques as the presence of hyperostosis along the longitudinal axis of teleosts does not allow a complete and repeatable filleting technique. This could increase the possibility of bacterial contamination, loss of muscle tissue, and imperfections in cutting and trimming.

Arca noae is one of four commercially exploited bivalves in the eastern Adriatic and it is a common dish in many Italian, Slovenian and Croatian regions, as both a raw and lightly cooked foodstuff. In this study, Arca noae samples collected along the Tyrrhenian coast near Patti (Sicily, Italy) were examined in order to assess their bacteriological characteristics and suitability for consumption. The total viable microrganisms (TVM), halophilc bacteria (HB), faecal coliforms, enterococci, Escherichia coli, Aeromonas hydrophila, Vibrio spp., and Salmonella spp. were determined. Presumptive Vibrio colonies were initially identified using biochemical tests, and strains identified as V. parahaemolyticus and V. alginolyticus were subsequently examined by PCR for the presence of different regulatory or virulence genes (toxR, toxRS, tl, trh, and tdh). In all samples, TVM and HB were very low ranging from 2.30 ± 0.35 to 3.52 ± 0.15 log cfu.g-1 and from 2.95 ± 0.22 to 3.65 ± 0.41 log cfu.g-1, respectively. Other bacteriological determinations were below the detection limits. The levels of Vibrio spp. contamination ranged from < 1.0 log cfu.g-1 (69.23% of samples) to 2.60 ± 0.31 log cfu.g-1. The qualitative method revealed the contamination of different potentially pathogenic Vibrio spp. in 86.41% of the samples. V. alginolyticus (55.56%) and V. parahaemolyticus (31.11%) were the most common species. All V. parahaemolyticus isolates were positive for the tl gene, while 78.57% were toxR(+), 14.21% toxRS(+), and only 7.14% toxR(+) toxRS(+). Among V. alginolyticus strains, 32% were toxR(+) and 4% toxR(+) toxRS(+). To our knowledge, this is the first report on the isolation of V. parahaemolyticus strains from A. noae bivalves collected along the Italian coasts. The results indicate that potentially pathogenic vibrios are frequently found in A. noae, despite the remaining low microbiological content, suggesting that routine examination of bivalve molluscs for these pathogenic agents is advisable.

In the present study, the chemical composition and the in vitro antimicrobial and antibiofilm activity of an ethanolic extract of propolis (EEP) from Tunisia against different ATCC and wild bacterial strains were evaluated. In situ antimicrobial activity and sensory influence of different EEP concentrations (0.5% and 1%), also in combination with 1% vinegar, were evaluated in chilled vacuum-packed salmon tartare. Furthermore, a challenge test was performed on salmon tartare experimentally contaminated with Listeria monocytogenes and treated with the different EEP formulations. The in vitro antimicrobial and antibiofilm activity was observed only against Gram-positive bacteria, such as L. monocytogenes and S. aureus, both ATCC and wild. Results of the in situ analyses revealed significant antimicrobial activity against aerobic colonies, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp. only when the EEP was used at 1% and in combination with 1% vinegar. The 1% EEP in combination with 1% vinegar was the most effective treatment also against L. monocytogenes, although 0.5% and 1% EEP used alone also showed antilisterial effects. After 7 days of storage, the sensory influence on odor, taste and color of salmon tartare was negligible for all EEP formulations. In this background, results obtained confirmed the antimicrobial efficacy of propolis which could be proposed as a suitable biopreservative to ensure safety and improve the quality of food.

The aim of the present study is to determine if Ahr ligands as PCB-126, a dioxin-like, might contribute to inhibition of the tumour suppressor p53 by promoting its degradation through proteasome-ubiquitin system (UPS). The findings show, in the presence of PCB-126, a significant increase in p53 immunoreactivity in fish compared to the control. Subsequently, there is a decrease in p53 immunoreactivity at 24h which is maintained even at 72h. There is also a slight decrease in ubiquitin immunoreactivity to 12h compared to the control and a marked decrease to 24 and 72h. It’s very important to underline as in this study we demonstrate a marked decrease in ubiquitin and p53 immunoreactivity at 24 and 72h. Our result emphasise the need to deeply the role of this receptor in UPS regulation as potential therapeutic target for cancer treatment

Three data sets concerning the behaviour of spoilage flora of fillets treated with natural preservative substances (NPS) were used to construct a new kind of mathematical predictive model. This model, unlike other ones, allows expressing the antibacterial effect of the NPS separately from the prediction of the growth rate. This approach, based on the introduction of a parameter into the predictive primary model, produced a good fitting of observed data and allowed characterising quantitatively the increase of shelf-life of fillets.

Summary A total of 217 Gilthead seabreams were subdivided in four groups, according to four different storage conditions. All fish were evaluated by both Quality Index Method (QIM) and microbiological analysis, sampling skin, gills and flesh, separately. A QIM score predictive system was set by modelling the growth of microflora of skin, gills and flesh and coupling these predictions to each related partial QIM score (QIMSkin, QIMGills, QIMFlesh). The expression of QIM score as a function of bacterial behaviour was carried out by the employment of two coefficients. The predicted mean bacterial concentrations corresponding to the QIM score at 14 days were always near to Log 8 CFU g−1 in the case of ‘S’ (skin) and ‘G’ (gills) series. Moreover, predicted QIM scores were in a good agreement with observed data, reproducing the observed mean time of rejection as well as the bacterial spoilage level (Log 8 CFU g−1), for all kinds of storage condition.

In this paper we review some results obtained within the context of the predictive microbiology, which is a specific field of the population dynamics. In particular we discuss three models, which exploit tools of statistical mechanics, for bacterial dynamics in food of animal origin. In the first model, the random fluctuating behaviour, experimentally measured, of the temperature is considered. In the second model stochastic differential equations are introduced to take into account the influence of physical and chemical variables, such as temperature, pH and activity water, subject to deterministic and random variations. The third model, which is an extended version of the second one, neglects the environmental fluctuations, and concentrates on the role of the interspecific bacterial interactions. The comparison between expected results and observed data indicates that the presence of noise sources and interspecific bacterial interactions improves the predictive features of the models analyzed.

During last years theoretical works shed new light and proposed new hypothesis on the mechanisms which regulate the time behaviour of biological populations in different natural systems. Despite of this, the role of environmental variables in ecological systems is still an open question. Filling this gap of knowledge is a crucial task for a deeper comprehension of the dynamics of biological populations in real ecosystems. In this work we study how the dynamics of food spoilage bacteria influences the sensory characteristics of fresh fish specimens. This topic is crucial for a better understanding of the role played by the bacterial growth on the organoleptic properties, and for the quality evaluation and risk assessment of food products. We therefore analyze the time behaviour, in fresh fish specimens, of sensory characteristics starting from the growth curves of two spoilage bacterial communities. The theoretical study, initially based on a deterministic model, exploits experimental temperature profiles. As a first step, a model of predictive microbiology is used to reproduce the experimental behaviour of the two bacterial populations. Afterwards, the theoretical bacterial growths are converted, through suitable differential equations, into "sensory" scores, based on the Quality Index Method (QIM), a scoring system for freshness and quality sensory estimation of fishery products. As a third step, the theoretical curves of QIM scores are compared with the experimental data obtained by sensory analysis. Finally, the differential equations for QIM scores are modified by adding terms of multiplicative white noise, which mimics the effects of uncertainty and variability in sensory analysis. A better agreement between experimental and theoretical QIM scores is observed, in some cases, in the presence of suitable values of noise intensity respect to the deterministic analysis., 25 pages, 12 figures, 1 table; to be published in Math. Model. Nat. Phenom