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The chemical composition as well as the antioxidant and antimicrobial activities of two EtOH extracts of propolis (PEEs) from Slovenia were determined. EtOH was used as extracting solvent at 70 and 96%, providing the extracts PEE70 and PEE96, respectively. The extraction with 70% EtOH was more efficient than that with 96% EtOH, as the PEE70 was richer in total phenolic compounds than the PEE96. The Slovenian propolis was characterized by different phenolic acids and flavonoids. The PEE96 was slightly richer in three specific compounds, i.e., caffeic acid, ferulic acid, and luteolin, while all other substances detected showed higher contents in the PEE70. The PEE70 showed a stronger reducing power and ability to scavenge free radicals and metal ions than the PEE96. Both PEEs were in the main more effective against Gram-positive bacteria than against fungi and Gram-negative bacteria like Salmonella and Escherichia coli, with the exception of Campylobacter. The PEE96 decreased the intracellular oxidation in Saccharomyces cerevisiae in a dose-dependent manner. The antimicrobial activities and antioxidant properties were related to the total phenolic contents. The two PEEs have the potential for use as natural antimicrobial and antioxidant additives in foods.

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Repetitive element sequence-based PCR (rep-PCR) was used to generate DNA fingerprints for Listeria spp. Two primer sets (REP 1R-I REP 2-I and ERIC 1R ERIC 2) used in respectively REP- and ERIC-PCR revealed that bacteria of the genus Listeria possess short repetitive extragenic palindromic elements and enterobacterial repetitive intergenic consensus sequences. Specific band profiles obtained by ERIC-PCR enabled the identification of Listeria species. With both REP- and ERIC-PCR the L. monocytogenes serotypes 1/2a, 1/2b, 1/2c, 3b and 4b could be clearly distinguished from each other. Within the serotype 1/2a, REP-PCR showed a higher discriminative potential than ERIC-PCR and a comparable discriminative potential as RAPD combining 3-4 primers.

Listeria monocytogenes strains possess short repetitive extragenic palindromic (REP) elements and enterobacterial repetitive intergenic consensus (ERIC) sequences. We used repetitive element sequence-based PCR (rep-PCR) to evaluate the potential of REP and ERIC elements for typing L. monocytogenes strains isolated from humans, animals, and foods. On the basis of rep-PCR fingerprints, L. monocytogenes strains were divided into four major clusters matching origin of isolation. rep-PCR fingerprints of human and animal isolates were different from those of food isolates. Computer evaluation of rep-PCR fingerprints allowed discrimination among the tested serotypes 1/2a, 1/2b, 1/2c, 3b, and 4b within each major cluster. The index of discrimination calculated for 52 epidemiologically unrelated isolates of L. monocytogeneswas 0.98 for REP- and ERIC-PCR. Our results suggest that rep-PCR can provide an alternative method for L. monocytogenes typing.