A. Vernile

Cloning, molecular characterization and expression analysis of two small heat shock genes isolated from wine Lactobacillus plantarum.

Aim:  Understanding the molecular response to stress tolerance of wine Lactobacillus plantarum.

Fresh-Cut Pineapple as a New Carrier of Probiotic Lactic Acid Bacteria

Due to the increasing interest for healthy foods, the feasibility of using fresh-cut fruits to vehicle probiotic microorganisms is arising scientific interest. With this aim, the survival of probiotic lactic acid bacteria, belonging to Lactobacillus plantarum and Lactobacillus fermentum species, was monitored on artificially inoculated pineapple pieces throughout storage. The main nutritional, physicochemical, and sensorial parameters of minimally processed pineapples were monitored. Finally, probiotic Lactobacillus were further investigated for their antagonistic effect against Listeria monocytogenes and Escherichia coli O157:H7 on pineapple plugs. Our results show that at eight days of storage, the concentration of L. plantarum and L. fermentum on pineapples pieces ranged between 7.3 and 6.3 log cfu g−1, respectively, without affecting the final quality of the fresh-cut pineapple. The antagonistic assays indicated that L. plantarum was able to inhibit the growth of both pathogens, while L. fermentum was effective only against L. monocytogenes. This study suggests that both L. plantarum and L. fermentum could be successfully applied during processing of fresh-cut pineapples, contributing at the same time to inducing a protective effect against relevant foodborne pathogens.

Occurrence of Giardia and Cryptosporidium in Italian water supplies

A total of 21 samples: raw water (RW) samples; water samples after coagulation with aluminium sulfate (clarified water: CW); and water after chlorination (treated water: TW) from a water purification plant that treats river surface water from the neighbourhood of Foggia (Italy), were analysed for the presence of Giardia cysts and Cryptosporidium oocysts. Bacteriological indicator of faecal contamination (total and faecal coliforms, faecal streptococci,), total bacterial count at 22 and 36°C and physicochemical parameters (turbidity, temperature, pH) were evaluated. Cryptosporidium oocysts were not found in any samples examined, while Giardia cysts were found only in RW samples, with the maximal concentration of 8 cysts/100 l. A positive correlation was found between the Giardia densities and quality parameters such as TC, FC and TBC at 22°C. Giardia levels in raw water samples correlated (p<0.05) with TC, FC and with temperature. No other water quality parameters was consistently correlated with cysts level.

Occurrence of Vibrio vulnificus in mussel farms from the Varano lagoon environment

Aims:  Monitoring the occurrence of the human pathogen Vibrio vulnificus in a mussel farm located in the lagoon of Varano (Italy).

PFGE: importance in food quality.

In late 19 century, great interest has arisen for food quality. This is referred as absence of pathogens in food (safety for consumers) and as nutritional quality of food (organoleptic characteristics). Pulsed-field gel electrophoresis (PFGE) is, among the molecular techniques developed in the last years, one of the most reliable, discriminative and reproducible technique. It can be used in clinical field for the identification of pathogens and the origin of outbreaks, and in food microbiology for the identification of pathogens (food borne disease surveillance) or of microorganisms responsible for the organoleptic characteristics of food. The present article shows some useful patents related to PFGE and importance in food quality.

PCR-based Quality Control of Listeria spp. and L. monocytogenes in Ready-To-Eat Salads Sold in Italy

A total of 48 samples of ready to-eat salads (RTE), containing different varieties of salads, of different brands sold in Italy, were purchased from several supermarkets, during period 2008 – 2009. This study was performed to determine whether microbial contamination, and in particular pathogenic bacteria, such as Listeria monocytogenes, were present in these food products. Samples were examined for mesophilic aerobic counts, yeasts and moulds, total and fecal coliforms, and presumptive Listeria monocytogenes counts. Results showed that, in general, the highest microorganism counts were associated with samples containing grated carrot (6.3 Log cfu g-1 of aerobic mesophilic microorganisms; 4.6 Log cfu g-1 of yeast and moulds; 2.8 Log cfu g-1 of total coliforms), while the lowest counts were, generally, associated with samples containing lettuce (2.8 Log cfu g-1 of aerobic mesophilic microorganisms; 2.3 Log cfu g-1 of yeast and moulds; 2.3 Log cfu g-1 of total coliforms). Of all the samples analyzed, only three (6 %) harboured L. monocytogenes.