Microbial quality of raw and ready-to-eat mung bean sprouts produced in Italy

The aim of this study was to determine the microbial quality of mung bean sprouts produced in Italy. The presence of pathogenic microorganisms (Shiga toxin- producing Escherichia coli (STEC), Salmonella spp. and Listeria monocytogenes), total coliforms, and total viable counts (TVCs) were determined. The study covered five years of sprout production. The results demonstrated that no pathogenic microorganisms were present, and the microbial load was less than 6 log CFU/g. The mung bean sprouts currently produced in Italy were found to be acceptable for consumption. An additional aim was to determine the fate of different strains of STEC, L. monocytogenes and Salmonella spp. by intentionally inoculating mung bean seeds during sprouting and by using chlorinated water to reduce the concentration of these strains in seeds and sprouts. The data demonstrated that these strains increased over 5\u20136 log CFU/g within 3 days from inocula. The chlorinated washing solution reduced the concentration of the investigated strains in seeds and sprouts by approximately 3 and 7 log CFU/g, respectively. However, it was not possible to completely eliminate the pathogens from either the mung bean seeds or sprouts. Despite these encouraging results, the producer's attention to hygienic quality should not be reduced when attempting to produce safe-to-consume mung bean sprouts

Phage Inactivation of Listeria monocytogenes on San Daniele Dry-Cured Ham and Elimination of Biofilms from Equipment and Working Environments

The anti-listerial activity of generally recognized as safe (GRAS) bacteriophage Listex P100 (phage P100) was demonstrated in broths and on the surface of slices of dry-cured ham against 5 strains or serotypes (i.e., Scott A, 1/2a, 1/2b, and 4b) of Listeria monocytogenes. In a broth model system, phage P100 at a concentration equal to or greater than 7 log PFU/mL completely inhibited 2 log CFU/cm2 or 3 log CFU/cm2 of L. monocytogenes growth at 30 \ub0C. The temperature (4, 10, 20 \ub0C) seemed to influence P100 activity; the best results were obtained at 4 \ub0C. On dry-cured ham slices, a P100 concentration ranging from 5 to 8 log PFU/cm2 was required to obtain a significant reduction in L. monocytogenes. At 4, 10, and 20 \ub0C, an inoculum of 8 log PFU/cm2 was required to completely eliminate 2 log L. monocytogenes/cm2 and to reach the absence in 25 g product according to USA food law. Conversely, it was impossible to completely eradicate L. monocytogenes with an inoculum of approximately of 3.0 and 4.0 log CFU/cm2 and with a P100 inoculum ranging from 1 to 7 log PFU/cm2. P100 remained stable on dry-cured ham slices over a 14-day storage period, with only a marginal loss of 0.2 log PFU/cm2 from an initial phage treatment of approximately 8 log PFU/cm2. Moreover, phage P100 eliminated free L. monocytogenes cells and biofilms on the machinery surfaces used for dry-cured ham production. These findings demonstrate that the GRAS bacteriophage Listex P100 at level of 8 log PFU/cm2 is listericidal and useful for reducing the L. monocytogenes concentration or eradicating the bacteria from dry-cured ham

Use of bacteriocin-producer Lactobacillus sakei for fermented sausages production

The aim of this paper was the technological characterization of a Lactobacillus sakei strain able to produce the bacteriocin sakacin P. Experiments were conducted in vitro, using MRS-based medium, and in vivo, when the strain was inoculated as starter culture in real sausage fermentation

Shelf-life evaluation of sliced cold-smoked rainbow trout (Oncorhynchus mykiss) under vacuum (PV) and modified atmosphere packaging (MAP)

Cold smoked trout (Oncorhynchus mykiss) is a traditional product from the San Daniele del Friuli area (Italy), usually packaged under vacuum, and its shelf life is 60 days. Aim of this study was to evaluate the influence of two different packaging systems (Vacuum packaging-VP and Modified atmosphere packaging-MAP) on the microbial, physico-chemical and sensorial changes of sliced cold smoked rainbow trout during storage. MAP packaged sample showed lower microbial loads than VP packaged sample throughout storage. Microbial count of VP packaged sample exceeded the limit of 6 log CFU/g after 60 days of storage. The total volatile base-nitrogen (TVB-N) values increased over time in both treatments, reaching values close to the limit of 40 mg N/100 g after 45 days. Also TBARS values did not were up to 10 nmol/g in both VP and MAP. The shelf life of 60 days seems to be too long, particularly for the VP samples. A panel composed of 12 nonprofessional assessors perceived significant differences in the sensorial characteristic of the samples, and concluded that the sensorial quality of MAP packaged products were better than the VP ones (P<0.05). \ua9 Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey in cooperation with Japan International Cooperation Agency (JICA), Japan

Application of PCR-DGGE for the identification of lactic acid bacteria in acitve dry wine yeasts

In this work a Polymerase Chain Reaction (PCR)-Denaturing Gradient Gel Electrophoresis (DGGE) protocol was used to identify the Lactic Acid Bacteria (LAB) contaminants in enological active dry yeasts routinely used in the wine production. The method is based on the PCR amplification of a DNA fragment from the region V1 of 16S rDNA gene followed by a DGGE technique. The main contaminant wasLactobacillus spp. andPediococcus spp

Biocontrol of ochratoxigenic moulds (Aspergillus ochraceus and Penicillium nordicum) by Debaryomyces hansenii and Saccharomycopsis fibuligera during speck production

Speck is a meat product obtained from the deboned leg of pork that is salted, smoked and seasoned for four to six months. During speck seasoning, Eurotium rubrum and Penicillium solitum grow on the surface and collaborate with other moulds and tissue enzymes to produce the typical aroma. Both of these strains usually predominate over other moulds. However, moulds producing ochratoxins, such as Aspergillus ochraceus and Penicillium nordicum, can also co-grow on speck and produce ochratoxin A (OTA). Consequently, speck could represent a potential health risk for consumers. Because A. ochraceus and P. nordicum could represent a problem for artisanal speck production, the aim of this study was to inhibit these mould strains using Debaryomyces hansenii and Saccharomycopsis fibuligera. Six D. hansenii and six S. fibuligera strains were tested in vitro to inhibit A. ochraceus and P. nordicum. The D. hansenii DIAL 1 and S. fibuligera DIAL 3 strains demonstrated the highest inhibitory activity and were selected for in vivo tests. The strains were co-inoculated on fresh meat cuts for speck production with both of the OTA-producing moulds prior to drying and seasoning. At the end of seasoning (six months), OTA was not detected in the speck treated with both yeast strains. Because the yeasts did not adversely affect the speck odour or flavour, the strains are proposed as starters for the inhibition of ochratoxigenic moulds

Preliminary analysis of the lipase gene (gehM) expression of Staphylococcus xylosus in vitro and during fermentation of naturally fermented sausages (in situ.

Coagulase-negative catalase-positive cocci (CNCPC) play a very important role during the fermentation of sausages. In particular, they are involved in the aroma formation of the final product, because they release lipases that are able to free short-chain fatty acids that are contributing to the sensory characteristics of the fermented sausage. Few studies have been undertaken to elucidate the regulation of lipase gene expression in Staphylococcus xylosus by substrate molecules or products of lipolysis. The aim of this study was to analyze the gehM gene expression of S. xylosus DSMZ 6179 in vitro with growth media containing different concentrations of lipids and in situ during the maturation of fermented sausages. The results obtained suggest that a concentration that increases in triglycerides in the growth medium suppresses the expression of the lipase gene

CALIBRAZIONE AGGREGATA DI MODELLI MRIO PER LA SIMULAZIONE DELLA DOMANDA MERCI A SCALA NAZIONALE

In this work, the Multi Regional Input-Output (MRIO) model was calibrated using aggregate datasets and applied to assess ex ante the economic impacts due to the implementation of new transportation infrastructures. The models were calibrated using all data available from national and regional statistical sources. The paper also reports an application to the appraisal of new infrastructures in Italy. Two scenarios were assessed: short and long-medium periods

Processing fresh mussels (M. galloprovincialis) by sous vide technology: effect on the microbiological characteristics

Sous-vide cook-chilled (SVCC) is used to describe food that has been vacuum-packed and given mild heat treatment under controlled conditions of time and temperature and subsequently rapidly cooled and stored at chilled conditions until heated before serving (Rhodehamel, 1992; Hansen et al., 1995). Limited studies reported the application of this process in aquacultural products (Espinosa et al., 2016; Shakila et al., 2009), such as trout fillets (Gonzalez-Fandos et al., 2004), 2009) and carp (Can, 2011) and there are no reports on the opportunities to apply such process to molluscs. The aim of the present research was to test the effect of the application of the SVCC technique on fresh mussel microbiological characteristics. Commercial Mediterranean mussels (M. galloprovincialis) were individually inoculated with 100 \ub5l suspension of Pseudomonas spp.(107 UFC/mL), packaged in a Oriented Polyamide/Polypropylene (OPA/PP, Orved S.p.A., Musile di Piave, VE, Italy) pouch and heat-sealed before being submitted to heat treatment in a steam oven (Lanoix Ali S.p.A., Treviso, Italy). After treatment, mussel pouches were immediately chilled at 3\ub0C. Six different time temperature combinations (75/85/95 \ub0C for 10 and 30 min), were tested in triplicate (3 specimens/group) and compared to raw and inoculated mussels. Total aerobic bacterial count (TBC), lactic acid bacteria (LAB), anaerobic sulphite-reducing clostridia, Pseudomonas spp. and pH were determined. All time/temperature combinations resulted in a substantial reduction of the Pseudomonas spp. population (<1 log CFU/g) both in raw (4.9 log CFU/g) and experimentally inoculated (5.7 log CFU/g) mussels. The homogenate pH values (6.22) resulted not affected by the heat treatment. Such results were confirmed on natural bacterial load of mussel. A TBC reduction (2.4 log and 3,5 log, respectively) was registered after treatment at 85 \ub0C both for 10 and 30 min, while the highest reduction (4.8 log) was observed at 95 \ub0C for 10 min confirming the efficacy of sous vide cook treatments even for fresh mussels. The technological and sensorial traits, as well the stability of these products both under refrigeration and thermal abuse conditions during storage need to be evaluated

Monitoring of a starter culture for fermented sausages by molecular methods

The ability of a commercial starter culture to perform a sausage fermentation was evaluated by culture -dependent and -independent methods. The starter culture, as well as the sausage during fermentation, was sampled and strains of lactic acid bacteria (LAB) and coagulase negative cocci (CNC) were isolated