Alessandro Giuffrida

Influence of slaughtering method on some aspects of quality of gilthead seabream and smoked rainbow trout.

The effects of several slaughter methods on the quality of fresh and smoked trout and fresh gilthead seabream were evaluated during storage at 2°C. Electrically stunned trout had slower ATP depletion of raw muscle and lower lipid oxidation in smoked product during storage. Gilthead seabream immersed in an ice slurry (IS group) after the harvest showed a more regular ATP depletion than in fish exposed to CO2. Nevertheless, in the case of the IS group, self-initiated behaviour, response to handling and breathing all ceased only after 15–20 min, whereas carbon dioxide-stunned fish appeared dead after 5 min. However, gilthead seabream group having slower ATP depletion also showed lower lipid oxidation of muscle during storage. In both species this could be due to the rapid conversion of xanthine dehydrogenase to xanthine oxidase induced by the rapid consumption of ATP. Xanthine oxidase, in the presence of redox iron and reintroduced oxygen, can produce hydrogen peroxide and, consequently, hydroxyl radicals.

Innovations in seafood preservation and storage.

The increasing amount of farmed fish cannot be easily absorbed by the market as only fresh fish. The production and promotion of value-added fresh and processed fish products, which could fulfil consumers’ present demands, may represent a solution to this problem. The aim of this paper is to review some of the most recent technologies, such as surface decontamination, use of “natural” additives and compounds, active packaging, used or experimented with to prolong shelf life, while ensuring the safety of fresh fish and fishery products.

Activity of Thymus vulgaris essential oil against Anisakis larvae

Anisakiasis is an important food-borne disease especially in countries with high fish consumption. The increase of cases of human disease and the virtual absence of effective treatments have prompted the research on new active compounds against Anisakis larvae. As well known, the disease is related to the consumption of raw or almost raw seafood products, but also marinated and/or salted fishery products, if the processing is insufficient to destroy nematode larvae can represent a risks for the consumers. In the light of the biocidal efficacy against different pathogens demonstrated for various essential oils, the aim of this work is to evaluate the effect of Thymus vulgaris essential oil (TEO) against anisakidae larvae. The TEO at 10% and 5% concentration in oil sunflower seeds, caused in vitro the death of all larvae within 14 h, with cuticle and intestinal wall damages. The results obtained showing a significant activity against Anisakis larvae, suggest further investigation on TEO as a larvicidal agent and on its potential use in the industrial marinating process.

Hygienic Evaluation of Marinated Sea Bass and Challenge Test for Listeria monocytogenes

Giuffrida, A., Ziino, G., Orlando, G. and Panebianco, A., 2007. Hygienic evaluation of marinated sea bass and challenge test for Listeria monocytogenes. Veterinary Research Communications, 31(Suppl. 1), 369–371

Antimicrobial activity of combined thyme and rosemary essential oils against Listeria monocytogens in Italian mortadella packaged in modified atmosphere: Thyme & Rosemary EOs vs L. monocytogenes

Abstract Listeria monocytogenes has been reported as a cause of illnesses related to the consumption raw and processed foods, contaminated during and/or after processing. The ability of L. monocytogenes to multiply at 4°C makes the occurrence in ready-to-eat (RTE) of particular concern. Nowadays, different strategies are applied in order to control pathogens in food products and in particular on the use of essential oils (EOs). The inhibitory effect of thyme and rosemary EOs (0.025% and 0.05%) was determined on a mix of three strains of L. monocytogenes in Italian mortadella packaged in modified atmosphere and stored at 4°C for 30 days. Thymol and p-cymene were the main components of thyme EO, while α-pinene, camphor and eucalyptol of rosemary EO. The use of combined rosemary and thyme EOs exhibited bacteriostatic activity against L. monocytogenes. After 30 days of storage L. monocytogenes charges in treated samples was lower of 2.29 log CFU/g in Group A and 2.79 log CFU/g in Group B compared with control samples. The sensory evaluation, showed the permanence of a strong odor related to EOs used. This work shows that the combined use of thyme and rosemary EOs could be used to control L. monocytogenes in mortadella.

Effect of Allyl Isothiocyanate against Anisakis Larvae during the Anchovy Marinating Process

Allyl isothiocyanate (AITC), is a natural compound found in plants belonging to the family Cruciferae and has strong antimicrobial activity and a biocidal activity against plants parasites. Anisakidosis is a zoonotic disease caused by the ingestion of larval nematodes in raw, almost raw, and marinated and/or salted seafood dishes. The aim of this work was to evaluate the effect of AITC against Anisakis larvae and to study its potential use during the marinating process. The effects of AITC against Anisakis larvae were tested in three experiment: in vitro with three liquid media, in semisolid media with a homogenate of anchovy muscle, and in a simulation of two kinds of anchovy fillets marinating processes. For all tests, the concentrations of AITC were 0, 0.01, 0.05, and 0.1%. Significant activity of AITC against Anisakis larvae was observed in liquid media, whereas in the semisolid media, AITC was effective only at higher concentrations. In anchovy fillets, prior treatment in phosphate buffer solution (1.5% NaCl, pH 6.8) with 0.1% AITC and then marination under standard conditions resulted in a high level of larval inactivation. AITC is a good candidate for further investigation as a biocidal agent against Anisakis larvae during the industrial marinating process.

Application of an interspecific competition model to predict the growth of Aeromonas hydrophila on fish surfaces during refrigerated storage

The growth of Aeromonas hydrophila and aerobic natural flora (APC) on gilthead seabream surfaces was evaluated during the refrigerated storage (21 days). The related growth curves were compared with those obtained by a conventional third order predictive model obtaining a low agreement between observed and predicted data (Root Mean Squared Error = 1.77 for Aeromonas hydrophila and 0.64 for APC). The Lotka-Volterra interspecific competition model was used in order to calculate the degree of interaction between the two bacterial populations (\beta_{Ah/APC} and \beta{APC/Ah}, respectively, the interspecific competition coefficients of APC on Aeromonas hydrophila and vice-versa). Afterwards, the Lotka-Volterra equations were applied as tertiary predictive model, taking into account, simultaneously, the environmental fluctuations and the bacterial interspecific competition. This approach allowed to obtain a best fitting to the observed mean growth curves with a Root Mean Squared Error of 0.09 for Aeromonas hydrophila and 0.28 for APC. Finally, authors carry out some considerations about the necessary use of competitive models in the context of the new trends in predictive microbiology.

Activity of R(+) limonene on the maximum growth rate of fish spoilage organisms and related effects on shelf-life prolongation of fresh gilthead sea bream fillets.

R(+)limonene (LMN) is the major aromatic compound in essential oils obtained from oranges, grapefruits, and lemons. The improvement of preservation techniques to reduce the growth and activity of spoilage microorganisms in foods is crucial to increase their shelf life and to reduce the losses due to spoilage. The aim of this work is to evaluate the effect of LMN on the shelf life of fish fillets. Its effectiveness was preliminarily investigated in vitro against 60 strains of Specific Spoilage Organisms (SSOs) and then on gilt-head sea bream fillets stored at 2±0.5°C for 15days under vacuum. LMN showed a good inhibitory effect against tested SSOs strains. On gilt-head sea bream fillets, LMN inhibited the growth SSOs effectively, and its use resulted in a shelf-life extension of ca. 6-9days of treated fillets, compared to the control samples. The LMN addition in Sparus aurata fillets giving a distinctive smell and like-lemon taste to fish fillets that resulted pleasant to panellists. Its use contributed to a considerable reduction of fish spoilage given that the fillets treated with LMN were still sensory acceptable after 15days of storage. LMN may be used as an effective antimicrobial system to reduce the microbial growth and to improve the shelf life of fresh gilt-head sea bream fillets.

Activity of R(+) limonene against Anisakis larvae

The aim of this work is to evaluate the activity of R(+) limonene of against Anisakidae larvae. Its effectiveness was tested in vitro. The results obtained showed a significant activity of the compound against Anisakis larvae, suggesting further investigation on its potential use in the industrial marinating process. In this regard, the use of R(+) limonene in seafood products could be interesting, also due the sensory attributes resulting from its use and its relatively safe status.

Effects of allyl isothiocyanate on the shelf-life of gilthead sea bream (Sparus aurata) fillets.

Muscolino D., Giarratana F., Beninati C., Ziino G., Giuffrida A., Panebianco A. (2016): Effects of allyl isothiocyanate on the shelf-life of gilthead sea bream (Sparus aurata) fillets. Czech J. Food. Sci., 34: 160–165. The effect of allyl isothiocyanate (AITC), a natural compound found in plants belonging to the family Cruciferae, on the shelf-life of fish fillets was evaluated. Preliminarily, the effectiveness of AITC was investigated in vitro against some strains of Specific Spoilage Organisms (SSOs). The inhibitory effect of AITC vapour was screened evaluating the bacterial growth in a jar. A strong inhibitory effect against the tested SSOs was observed. Successively, the shelf-life of gilthead sea bream fillets treated with AITC vapour and stored at 2°C was evaluated and compared with untreated samples. AITC inhibited the growth of SSOs effectively, and its use resulted in a shelf-life extension by ca. 8 days in treated fillets, compared to the control samples. The AITC addition in fillets yielded a distinct but pleasant flavour and contributed to a considerable reduction of fish spoilage.