Chiara Beninati

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.

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.

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.

ESBL-producing bacteria and MRSA isolated from poultry and turkey products imported from Italy.

Beninati C., Reich F., Muscolino D., Giarratana F., Panebianco A., Klein G., Atanassova V. (2015): ESBL-producing bacteria and MRSA isolated from poultry and turkey products imported from Italy. Czech J. Food Sci., 33: 97–102. ESBL and MRSA-producing bacteria in food-producing animals may contribute to increased incidences of infection in humans. This study was carried out on 38 samples obtained from 32 chickens and 6 turkey products purchased at retail outlets of Hannover (Germany) and imported from Italy. The samples included the thigh, breast fillet, gizzard, sausage, liver, heart, and roll, and were processed for the detection of ESBL producing E. coli and MRSA producing Staphylococcus aureus . Twenty-six chicken products (68.4%) of the total of poultry products analysed proved to be positive for E. coli and for phenotypical detection of ESBL. Six turkey products (100%) were positive for ESBL produc ing E. coli . Staphylococcus aureus was found in 4 chicken products (10.52%) that resulted positive in the detection of MRSA. Serratia spp. were reported in 4 samples that were also positive for ESBL. Thirty-three E. coli isolates from the poultry and turkey products were all resistant to at least one or more of the compounds tested. The highest resistance levels were observed, notably, against ampicillin and cefotaxim.

Hygienic-sanitary evaluation of sushi and sashimi sold in Messina and Catania, Italy

Sushi and sashimi are traditional Japanese food, mostly consisting of raw seafood alone or in combination with rice. Eating sushi and sashimi has become popular in many countries even outside Japan. This food is not free from health risks such as ingestion of pathogenic bacteria or parasite. The aim of this study was to investigate on hygienic-sanitary quality of sushi and sashimi sold in the cities of Messina and Catania, Southern Italy. Fifty samples (38 sushi and 12 sashimi) were analysed to determinate the aerobic mesophilic bacteria (AMB), psycrophilic bacteria (PB), Enterobacteriaceae, specific spoilage organisms (SSOs), Pseudomonas spp., coagulase-positive staphylococci, micrococci, Vibrio spp., Bacillus cereus, Salmonella spp. and Listeria monocytogenes. In sushi, AMB ranged from 5.00 to 8.18 log CFU/g, PB from 4.70 to 7.13 log CFU/g, Enterobacteriaceae from 1.41 to 6.67 log CFU/g, while SSOs and Pseudomonas spp. from 3.49 to 7.72 and from 3.36 to 8.00 log CFU/g, respectively. Micrococci ranged from 3.53 to 5.03 log CFU/g and coagulase positive staphylococci were found in 16 samples (2.00 to 3.60 log CFU/g). Bacillus cereus was found in 3 samples (1.70 to 4.00 log CFU/g), while Vibrio spp. was found in 15 of the sushi samples (1.70 to 3.70 log CFU/g). In sashimi, the AMB, PB and SSOs values were higher than 7.00 log CFU/g, Pseudomonas spp. and Enterobacteriaceae were from 6.00 to 8.00 log CFU/g, while Vibrio spp. were found in six samples with means of 2.00 log CFU/g. No Salmonella spp. and Listeria monocytogenes were detected in all sushi and sashimi samples.

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.

Preliminary investigation on the use of allyl isothiocyanate to increase the shelf-life of gilthead sea bream (Sparus aurata) fillets

The aim of this work is to evaluate the activity of allyl isothiocyanate (AITC) against fish spoilage bacteria (specific spoilage organisms; SSOs) as well as its possible use in gilthead sea bream (Sparus aurata) fillets to extend their shelf-life. In this regard, in vitro tests are carried out in order to evaluate the inhibitory activity of AITC and its vapours on several strains of SSOs. The AITC effect on the shelf-life of sea bream fillets was made by putting them in plastic trays hermetically closed with the addition AITC. Microbiological and sensorial evaluations were made on fish fillets during storage. Treated fillets maintained microbial populations at a significantly lower level compared with the control samples during storage, showing better sensorial characteristics. Therefore, the use of AITC’s vapours seems to be a new and interesting alternative way to increase fish product shelf-life.

Characterisation of yeasts isolated from 'Nduja of Spilinga

The ‘Nduja of Spilinga protected geographical indication (PGI) is a spreadable italian salami, obtained by using fat (50%), lean of pork (25%), chili pepper (25%) and NaCl, stuffed into natural pork casing. Its predominant flora is represented by yeasts, reaching at the end of seasoning values of 6 log CFU/g. Considering the need to enhance and protect traditional local products, it seemed interesting to carry out a characterisation of yeasts of the ‘Nduja of Spilinga PGI. A total of 127 strains of yeast isolated from samples of ‘Nduja of Spilinga PGI (79 strains from samples at different days of curing and 48 from samples of commerce) was subjected to morphological identification, hydrolysis of urea, lipolytic activity and identification with API 20C AUX, ID 32C and simplified identification systems. One hundred twenty three (96.8%) strains were attributable to the phylum Ascomycetes (urease-negative), the remaining 4 strains (3.2%) were Basidiomycetes (urease-positive). Debaryomyces hansenii and its anamorph shape, Candida famata, represented the most prevalent species (61.42 and 17.32% respectively), followed by Candida glabrata (8.66%), Pichia (Candida) guilliermondii (5.17%), Candida parapsilosis and Rhodotorula glutinis (1.57%). Candida catenulata, Criptococcus uniguttulatus, Rhodotorula minuta, Candida zeylanoides and Candida utilis were observed with 0.79%. The lipolytic activity was observed only in 10 strains of D. hansenii and in one of C. zeylanoides. Further investigation will contribute to the selection of indigenous strains that could be used for the creation of specific starter, useful to improve the process of characterisation of the ‘Nduja of Spilinga and also to guarantee its safety.