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Abstract In the present work, a combined hurdle approach for fermented meat preservation was investigated. Challenge tests were performed in Chorizo sausage model using the maximum allowed NaNO 2 amount (150 mg/kg), a reduced amount (75 mg/kg) and no nitrite, with and without protective cultures inoculation. Cocktail strains of L. monocytogenes and Salmonella spp. were used as indicator strains. In a nitrite reduced sausage model, L. monocytogenes growing trend did not significantly change (p > 0.05) when compared with that containing higher nitrite concentration (150 mg/kg NaNO 2). The addition of L. plantarum PSC20 significantly lowered L. monocytogenes growth when compared with control batches without PCS20 (p < 0.05), obtaining 3.84 log cfu/g and 2.62 log cfu/g lower counts in the batches with 150 mg/kg NaNO 2 and 75 mg/kg NaNO 2 respectively. None of the protective cultures demonstrated in situ antagonistic activity against Salmonella spp. This work pointed out that the reduction of nitrites with the combined use of a protective culture could be a feasible approach to control L. monocytogenes growth in fermented meat foods. Highlights • L. plantarum PCS20 strain is an effective protective culture in fermented meat. • A reduced nitrite amount and a protective culture is a promising hurdle approach. • A complete nitrite elimination may not be effective against all meat pathogens. [ABSTRACT FROM AUTHOR]

The capability of ten commercial fibers of selectively stimulating the growth of four Bifidobacterium strains were studied with the purpose of developing a synbiotic product for infants. Two galacto-oligosaccharides (GOS), one fructo-oligosaccharide (sc-FOS), four inulins with different polymerization degree (DP), a gluco-oligosaccharide, an arabinogalactan and a hydrolyzed guar gum were used (10 gl −1 ). The prebiotic score was calculated comparing the capability of the fibers of stimulating the growth of bifidobacteria compared to infant pathogens. GOS, sc-FOS, low DP inulin (oligofructose) and the gluco-oligosaccharide could stimulate growth. However, the fibers showing the highest prebiotic score were oligofructose (Orafti ® HIS), sc-FOS (Actilight ® 950P) and the GOS Vivinal ® . Lyophilized strain survival in simulated gastro-intestinal conditions was also assayed to define suitable ways of administration. Survival in gastric juice at pH 2.5 was poor, whereas it was higher at pH 4, a value closer to newborn pH. Microencapsulation in a lipid matrix ensured strain survival also at pH 2.5. Survival to 1 gl −1 bile salts was acceptable. The results allowed to conclude that Bifidobacterium breve B632 strain, in a lyophilized or microencapsulated form, has the potential for use in synbiotic products targeted to infants coupled to a mixture of GOS and FOS or oligofructose. [ABSTRACT FROM AUTHOR]

The growing concern on the antibiotic resistance spreading among bacteria has stimulated the search for valuable alternatives from plant sources. This study dealt with the potential use of hemp (Cannabis sativa L.) seeds extract to inhibit the growth of selected pathogenic enterobacteria and the biofilm formation by Staphylococcus aureus , representing severe risks of food-borne illnesses. Effects on probiotic bacteria were also examined. A double-staining viability/mortality assay was used to examine potential S. aureus membrane damage. Our results highlighted a selective antimicrobial activity of C. sativa extract against pathogenic strains and no inhibitory effects on the growth of probiotic strains belonging to the Bifidobacterium and Lactobacillus genera. This selective inhibition is of outmost importance for the maintenance of healthy gut microbiota. The double-staining assay showed that the C. sativa extract was capable of inhibiting the biofilm producer S. aureus ATCC 35556 strain; this antibacterial action was only partially linked to membrane damage. Biofilm formation was inhibited as well; inhibition occurs at lower concentration with respect to planktonic cells (0.5 mg/ml vs 1 mg/ml, respectively). Therefore, hemp seeds extracts represent a new exploitable and valuable antimicrobial and antibiofilm agent for the food and nutraceutical industry as a possible alternative to antibiotics/antibacterial compounds. Image 1 • Cannabis sativa L. seeds showed antimicrobial and antibiofilm activity. • C. sativa L. seeds selectively inhibit the growth of potentially pathogenic strains. • C. sativa L. seeds did not exert antimicrobial activity against probiotic bacteria. • C. sativa L. seeds inhibit the biofilm formation by Staphylococcus aureus. [ABSTRACT FROM AUTHOR]