4 research outputs found
A survey of soft cheeses in Greek retail outlets highlights a low prevalence of Listeria spp.
Recently, the European Food Safety Authority proposed that each EU
member state should conduct a survey of Listeria monocytogenes in soft
cheeses for sale in retail outlets. Hence, retail samples of soft
cheeses in Greece (n = 137) were analyzed qualitatively and
quantitatively for both L. monocytogenes and other Listeria spp., as
well as for pH and a (w). None of the cheeses analyzed were found
positive for L. monocytogenes (0%; 95% confidence interval (CI) =
0.0-2.2%). Three samples (2.2%; 95% CI = 0.5-6.3%) were positive for
other Listeria spp., with populations ranging from < 5 to 4.5 x 10(2)
CFU g(-1). Although soft cheeses are regarded as foods that permit the
proliferation of L. monocytogenes, 15.4% of the whey cheeses tested had
pH values a parts per thousand currency sign4.4 and 29% of the interior
mold-ripened cheeses had a (w) values a parts per thousand currency
sign0.92. Such low pH values for whey cheeses are unexpected, based on
their manufacturing technology, and are associated with lower quality
and reduced shelf life. Nonetheless, in the present survey, the
percentage of whey cheeses in the Greek retail market exhibiting
unusually low pH values or testing positive for Listeria spp. was much
lower compared to the respective percentages reported from studies
conducted in the 1990s. The absence of L. monocytogenes in the tested
cheeses undoubtedly constitutes an encouraging result with respect to
the safety of soft cheeses in the Greek retail market. However, the
presence of other Listeria spp. in three of the tested samples implies
that L. monocytogenes would, most likely, also be present in the
food-processing or retail-handling environments of these products.
Therefore, cheese manufacturers and retail handlers should continue or
even intensify the application of all necessary measures with the aim of
preventing food contamination
Cave Cyanobacteria showing antibacterial activity
Cave Cyanobacteria - thriving in an ‘extreme’ environment with interesting species biodiversity - are supposed to be a potential source of bioactive compounds. Lipid extracts from pure cultures of two recently established Cyanobacteria from Greek caves, Toxopsis calypsus and Phormidium melanochroun, were used for antibacterial screening against human pathogenic bacteria (reference and clinical isolates). Antimicrobial Susceptibility testing for both taxa was carried out using the disc-diffusion (Kirby Bauer) method, while preliminary data applying the standard broth microdilution method for the determination of the Minimal Inhibitory Concentration (MIC) are given only for T. calypsus. Antibacterial activity was demonstrated against the Gram-positive clinical and reference bacteria, mostly pronounced in enterococci; no activity was observed against the Gram-negative bacteria. The above screening is the first record of antibacterial activity from lipid extracts of cave Cyanobacteria enhancing the importance of cave microbiota and the necessity for cave conservation
Cave Cyanobacteria showing antibacterial activity
Cave Cyanobacteria - thriving in an ‘extreme’ environment with interesting species biodiversity - are supposed to be a potential source of bioactive compounds. Lipid extracts from pure cultures of two recently established Cyanobacteria from Greek caves, Toxopsis calypsus and Phormidium melanochroun, were used for antibacterial screening against human pathogenic bacteria (reference and clinical isolates). Antimicrobial Susceptibility testing for both taxa was carried out using the disc-diffusion (Kirby Bauer) method, while preliminary data applying the standard broth microdilution method for the determination of the Minimal Inhibitory Concentration (MIC) are given only for T. calypsus. Antibacterial activity was demonstrated against the Gram-positive clinical and reference bacteria, mostly pronounced in enterococci; no activity was observed against the Gram-negative bacteria. The above screening is the first record of antibacterial activity from lipid extracts of cave Cyanobacteria enhancing the importance of cave microbiota and the necessity for cave conservation