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Ricotta cheese is a potential growth medium for a wide range of microorganisms. The aim of the current study was to investigate the efficacy of ultraviolet (UV-C) and near-ultraviolet–visible light (NUV–vis) in microbial decontamination of ricotta artificially inoculated with Pseudomonas fluorescens. Cheese samples were stored at 4 °C, and microbiological and sensory analyses were performed for 9 days. From the microbiological point of view, control samples became unacceptable after less than 5 days, whereas ricotta treated by both UV-C and NUV–vis light remained acceptable for more than 6 days. Similar effects of UV-C and NUV–vis light were also recorded in terms of sensory quality. The shelf life of the samples subjected to the treatments was thus extended by 50%, suggesting the potential application of UV-C and NUV–vis light for cheese decontamination.

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The aim of this paper was to study the potential technological and probiotic properties of bifidobacteria isolated from human feces. Bifidobacteria, naturally present in the dominant colonic microbiota, represent up to 25% of the cultivable faecal bacteria in adults and 80% in infants. Bifidobacteria have been shown to adhere and colonize in high numbers different types of cultured intestinal epithelial cells; moreover some authors reported that some strains are able to stabilize the intestinal microbiota during and after antibiotic therapy, modulate the immune system, protecting against chemically induced intestinal inflammation and reducing symptoms of colitis. Eight isolates of bifidobacteria were studied to assess their technological and probiotic traits; the technological characterization relied on the assessment of enzymatic activities (proteolytic and lipolytic activity), growth under various conditions (pH, temperature and addition of salt), acidifying ability and metabolism (arginine deamination, esculin, esculin hydrolysis and citrate metabolism). The study of the probiotic characteristics focused on the evaluation of the survival at low pH and with bile salts added, antibiotic resistance, and hydrophobic properties. As a result of this process, two promising strains were selected for further studies.