Cristian Bernardi

Prevalence and mean intensity of Anisakis simplex (sensu stricto) in European sea bass (Dicentrarchus labrax) from Northeast Atlantic Ocean

Viscera and muscle of a total of 40 wild 1-2kg European sea bass (Dicentrarchus labrax) from Northeast Atlantic (FAO area 27) were examined for Anisakidae larvae detection by digestion method. Extracted parasites were counted and mean intensity was calculated. Parasites were identified by genetic/molecular markers (allozymes and sequences analysis of the mtDNA cox2 gene) as belonging to the species Anisakis simplex (sensu stricto). In viscera, the main localisations of the larvae were under the gastric serosa, where several parasites alive and dead were found, and intestinal serosa. The visceral prevalence was 0.950 and the mean intensity was 96.39. The main localisation of A. simplex (s.s.) in edible parts was in belly muscles, with a prevalence of 0.425 and a mean intensity of 1.9. This is the first record on the prevalence and mean intensity of A. simplex (s.s.) in European sea bass muscle. This finding has an important consequence on epidemiology of anisakiasis and public health risk assessment.

Microbiological shelf life at different temperatures and fate of Listeria monocytogenes and Escherichia coli inoculated in unflavored and strawberry yogurts

Three different trials were performed on unflavored and strawberry yogurts produced in a small-scale dairy plant. In the first trial, the microbiological shelf life of the products was evaluated at 4, 8, and 20°C. At 4°C the product showed low total viable counts until the end of the trial (d 35=3.0±0.7 and 1.5±0.0 log cfu/g in unflavored and strawberry yogurt, respectively). The loads were lower in strawberry yogurt at 4°C compared with unflavored yogurt because of the antimicrobial activity exerted by potassium sorbate present in the fruit puree added. Yeasts were confirmed to be the specific spoilage agents of this product, reaching rapidly high loads with thermal abuse (5.9-7.4 log cfu/g at d 18). In the second trial, Escherichia coli and especially Listeria monocytogenes added at 2 concentrations (2 and 5 log cfu/g) showed a rapid decrease in both types thanks to the acidic conditions provided by the products, but L. monocytogenes was very resistant; its presence was always detected until the end of the period considered (d 68). In the third trial, no statistically significant differences were detected between wild and acid-adapted strains of L. monocytogenes added to the products, due to the quick adaptation that probably occurred after inoculation.

First Results of a Detection Sensor for the Monitoring of Laying Hens Reared in a Commercial Organic Egg Production Farm Based on the Use of Infrared Technology.

The development of a monitoring system to identify the presence of laying hens, in a closed room of a free-range commercial organic egg production farm, was the aim of this study. This monitoring system was based on the infrared (IR) technology and had, as final target, a possible reduction of atmospheric ammonia levels and bacterial load. Tests were carried out for three weeks and involved 7 ISA (Institut de Sélection Animale) brown laying hens. The first 5 days was used to set up the detection sensor, while the other 15 days were used to evaluate the accuracy of the resulting monitoring system, in terms of sensitivity and specificity. The setup procedure included the evaluation of different color background (CB) thresholds, used to discriminate the information contents of the thermographic images. At the end of this procedure, a CB threshold equal to an increase of 3 °C from the floor temperature was chosen, and a cutoff level of 196 colored pixels was identified as the threshold to use to classify a positive case. The results of field tests showed that the developed monitoring system reached a fine detection accuracy (sensitivity = 97.9% and specificity = 94.9%) and the IR technology proved to be a possible solution for the development of a detection sensor necessary to reach the scope of this study.

Former food products safety: microbiological quality and computer vision evaluation of packaging remnants contamination

ABSTRACT The use of alternative feed ingredients in farm animal’s diets can be an interesting choice from several standpoints, including safety. In this respect, this study investigated the safety features of selected former food products (FFPs) intended for animal nutrition produced in the framework of the IZS PLV 06/14 RC project by an FFP processing plant. Six FFP samples, both mash and pelleted, were analysed for the enumeration of total viable count (TVC) (ISO 4833), Enterobacteriaceae (ISO 21528-1), Escherichia coli (ISO 16649-1), coagulase-positive Staphylococci (CPS) (ISO 6888), presumptive Bacillus cereus and its spores (ISO 7932), sulphite-reducing Clostridia (ISO 7937), yeasts and moulds (ISO 21527-1), and the presence in 25 g of Salmonella spp. (ISO 6579). On the same samples, the presence of undesired ingredients, which can be identified as remnants of packaging materials, was evaluated by two different methods: stereomicroscopy according to published methods; and stereomicroscopy coupled with a computer vision system (IRIS Visual Analyzer VA400). All FFPs analysed were safe from a microbiological point of view. TVC was limited and Salmonella was always absent. When remnants of packaging materials were considered, the contamination level was below 0.08% (w/w). Of note, packaging remnants were found mainly from the 1-mm sieve mesh fractions. Finally, the innovative computer vision system demonstrated the possibility of rapid detection for the presence of packaging remnants in FFPs when combined with a stereomicroscope. In conclusion, the FFPs analysed in the present study can be considered safe, even though some improvements in FFP processing in the feeding plant can be useful in further reducing their microbial loads and impurity. Graphical Abstract

Prevalence and Mean Intensity of Anisakidae Parasite in Seafood Caught in the Mediterranean Sea Focusing on Fish Species at Risk of Being Raw-consumed. A Meta Analysis and Systematic Review.

Objective: To assess the prevalence and mean intensity of anisakids in seafood caught in the Mediterranean Sea, focusing on fish species at risk of being raw-consumed. Design: Systematic review and meta-analysis of studies published from 1960–2012. Study selection: Main criteria for the inclusion of studies were as follows: Findings of anisakid larvae, in both muscles and viscera; fish species for human consumption caught in the Mediterranean Sea; prevalence and mean intensity data for each species; and sample size equal to or more than 40 fishes. Results: Twelve studies were identified. Among these, four studies considered the following three fish species that are often consumed raw or preserved lightly, or not cooked thoroughly: anchovy, pilchard, and Atlantic mackerel. Data synthesis: All pooled analyses were based on the random-effect model. Anisakids prevalence in fish muscle was 0.64% (P < 0.0001), in viscera it was 1.34% (P < 0.0001), and overall prevalence was 0.95% (P < 0.0001). Mean intensity in muscle was 2.31 (P = 0.0083), in viscera it was 1.55 (P = 0.0174), and overall it was 1.81 (P < 0.0005). Heterogeneity indices (I2) were significantly high with the exception of viscera mean intensity. Conclusions: Anchovy, pilchard, and Atlantic mackerel have a low prevalence and mean intensity of anisakidae larvae in both viscera and muscles. Mean Intensity was also low.

Influence of Skin Packaging on Raw Beef Quality: A Review

A detailed revision of several aspects related to the application of skin packaging to raw beef was considered. Skin packaging, a relatively new technique derived from vacuum packaging, was developed with the aim of retailing small portions of fresh meat, minced meat, or meat preparations. Above all, the influence of this typology of packaging on the microbial population of raw meat was studied, with particular attention to total viable count, aerobic spoilage bacteria, anaerobic bacteria, Enterobacteriaceae, Brochothrix thermosphacta, and lactic acid bacteria. Moreover, the effect on acidification by LAB was also deepened. As colour is the main characteristic influencing purchase decisions at the point of sale, the effect of skin packaging on this parameter was evaluated for raw meat but also for cooked meat. Tenderness, juiciness, and the ability to hold liquid of raw meat when packed in skin conditions were also considered. Furthermore, odour and flavour were considered as sensorial parameters possibly affected by skin packaging. Finally, acceptability by consumer was also investigated. In the studies considered, results showed that skin packaging is advantageous in terms of maintenance of meat quality and for prolonging shelf-life, improving the stability of the products.

Functional characterization of Lactobacillus plantarum ITEM 17215: A potential biocontrol agent of fungi with plant growth promoting traits, able to enhance the nutritional value of cereal products

In this work, we explored the potential of 25 Lactobacillus plantarum strains isolated from cereals and milk-based products, testing characteristics related to antifungal activity and to nutritional quality. The tested strains demonstrated interesting beneficial traits, such as the ability to utilize fructo-oligosaccharides, prebiotic substances that help probiotic microorganisms to grow in the human gut, and to reduce phytate, an antinutrient present in cereal sector. Regarding mould inhibition, we highlighted the ability of the strains to inhibit Penicillium roqueforti, Mucor circinelloides and mycotoxinogenic moulds associated with cereal grains as Aspergillus flavus, A. niger, Fusarium verticillioides. Moreover, a moderate reduction of the bioavailability of aflatoxin AFB1 was detected. The selected L. plantarum strain ITEM 17215, showed a strong inhibitory ability towards fungal growth and was able to produce 1,2-dihydroxybenzene, benzoic acid, p-hydroxyphenyllactic acid and 3-phenyllactic acid. The latter compound, already described as efficient antifungal inhibitor, was the most abundant and its concentration was further increased by adding phenylalanine and phenylpyruvic acid in the growth medium. The metabolites produced by strain ITEM 17215 could also be related to the ability of the strain to induce cereal germination and promote plant growth. This aspect, not yet investigated in L. plantarum, could have interesting applications in the agro-food sector.

American lobsters (Homarus americanus) not surviving during air transport: evaluation of microbial spoilage

Eighteen American lobsters (Homarus americanus), dead during air transport, were analysed in order to evaluate the microbial population of meat, gills and gut: no specific studies have ever been conducted so far on the microbiological quality of American lobsters’ meats in terms of spoilage microbiota. The meat samples showed very limited total viable counts, in almost all the cases below the level of 6 Log CFU/g, while higher loads were found, as expected, in gut and gills, the most probable source of contamination. These data could justify the possibility to commercialise these not-surviving subjects, without quality concerns for the consumers. Most of the isolates resulted to be clustered with type strains of Pseudoalteromonas spp. (43.1%) and Photobacterium spp. (24.1%), and in particular to species related to the natural marine environment. The distribution of the genera showed a marked inhomogeneity among the samples. The majority of the isolates identified resulted to possess proteolytic (69.3%) and lipolytic ability (75.5%), suggesting their potential spoilage ability. The maintanance of good hygienical practices, especially during the production of ready-to-eat lobsters-based products, and a proper storage could limit the possible replication of these microorganisms.

Effect of ageing time in vacuum package on veal longissimus dorsi and biceps femoris physical and sensory traits

Study evaluated the effects of vacuum ageing (2, 4, 6, 8, 10, 12, 16 days) on veal loin (longissimus dorsi; LD) and silverside (biceps femoris; BF) physical and sensory characteristics. Ageing did not affect cooking loss, increased LD pH and L*, a* and b* in both muscles. Shear force (SF) decreased until day 6 in LD and day 10 in BF. Aroma, flavor and taste were not affected, while texture traits were improved. SF was negative correlated with tenderness and juiciness and positive correlated with BF fibrousness and stringy sensation. Ageing improved texture properties without altering other sensory traits.

Predicting growth of Listeria monocytogenes in fresh ricotta

Challenge tests with eight brands of fresh ricotta showed rapid growth of Listeria monocytogenes and significant variability in physical-chemical characteristics. Thus, two cardinal parameters models were developed for the growth of L. monocytogenes in ricotta including, respectively, terms for temperature (Model 1) and temperature and pH (Model 2). Also an extensive, existing growth model including the effect of organic acids (Model 3) was product recalibrated to predict growth of L. monocytogenes in ricotta. Interestingly, a lack of anti-listerial effect of organic acids in ricotta was observed in this study. The range of applicability of Models 1 and 2 in ricotta (characterized by absence of competitive microbiota) included storage at temperatures from 4.1 to 20.6 °C, pH from 5.5 to 6.6, moisture contents from 72% to 82%, NaCl from 0.38% to 0.60%, concentrations of acetic acid from 579 to 1559 ppm in the water phase, citric acid from 14,774 to 46,116 ppm in the water phase, and lactic acid from 0 to 4146 ppm in the water phase. Comparing observed and predicted maximum specific growth rates of L. monocytogenes in ricotta showed a bias-factor significantly above 1, for existing models developed for broth and these models were thus fail-safe with predicted growth being faster than observed, while typically below 1 for models developed for other food types. The models developed in the present study showed bias-factors of 1.10, 1.06 and 0.78, respectively, for Model 1, 2, and 3. In particular, Model 1 and 2 developed and successfully validated could allow an easy determination of safe shelf-life of ricotta and facilitated the reformulation the product with the aim to increase shelf-life or safety.