a b s t r a c tThe purpose of this study was to evaluate the effects of the application of chitosan coating containing natamycin on the physicochemical and microbial properties of semi-hard cheese. Three cheese groups were prepared: samples without coating, samples coated with chitosan and with chitosan containing 0.50 mg mL À1 of natamycin, whose minimum inhibitory concentration was previously determinated on cheese surface. Microbiological analyses showed that natamycin coated samples presented a decrease on moulds/yeasts of 1.1 log (CFU g À1 ) compared to control after 27 days of storage. Addition of natamycin also affected O 2 and CO 2 permeability, increasing from 7.12 to 7.68 Â 10 À15 gÁ(Pa s m) À1 , and from 10.69 to 64.58 Â 10 À14 gÁ(Pa s m) À1 , respectively. The diffusion coefficient values of natamycin from the film to phosphate buffered saline solution and to the cheese were 3.60 Â 10 À10 and 1.29 Â 10 À12 cm 2 s À1 , respectively. This study demonstrated that chitosan-based coating/films can be used as release system containing natamycin to create an additional hurdle for moulds/yeasts in cheese thus contributing to extend its shelf-life.

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The aim of this study was to evaluate the potential of two probiotic preparations, containing live lactic acid bacteria (Lactococcus lactis CECT 539 and Lactobacillus casei CECT 4043) and their products of fermentation (organic acids and bacteriocins), as a replacement for antibiotics in stimulating health and growth of broiler chickens. The effects of the supplementation of both preparations (with proven probiotic effect in weaned piglets) and an antibiotic (avilamycin) on body weight gain (BWG), feed intake (FI), feed consumption efficiency (FCE), relative intestinal weight, and intestinal microbiota counts were studied in 1-day posthatch chickens. The experiments were conducted with medium-growth Sasso X44 chickens housed in cages and with nutritional stressed Ross 308 broiler distributed in pens. Consumption of the different diets did not affect significantly the final coliform counts in Sasso X44 chickens. However, counts of lactic acid bacteria and mesophilic microorganisms were higher in the animals receiving the two probiotic preparations (P < 0.05). In the second experiment, although no differences in BWG were observed between treatments, Ross 308 broilers receiving the probiotic Lactobacillus preparation exhibited the lowest FCE values and were considered the most efficient at converting feed into live weight.