Physicochemical and microbiological evaluation of corrientes artisanal cheese during ripening

Biodiversity of wild Lactococcus lactis and their geo-spatial relationship with the environment

Lactic acid bacteria are distributed in nature, isolating themselves from diverse ecosystems and presenting a wide metabolic biodiversity. In Corrientes (Argentina), artisanal cheeses and their specific environment are an important source of autochthonous lactic acid bacteria. The objective of this work was to establish associations between the phenotypic characteristics of strains of Lactococcus lactis subsp. lactis native from Corrientes with climatological data of the Province and the characteristics of the soil and the landscapes. Physiological and biochemical characterization data of Lactococcus lactis subsp. lactis isolated from the dairy environment and from different localities of Corrientes will be used. The strains were space-located through Google Earth, flood and drought events were evaluated using Standardized Precipitation Evapotranspiration Index, and soil composition data (A and Bt horizons) in the study areas were obtained from the experimental station National Institute of Agricultural Technology - Corrientes. A statistical analysis was applied to these results (Infostat Software, Di Rienzo et al. 2008). The resulting consists in three conglomerates, differentiating strains from soils coming from "flooded landscapes" and those from "sandy hills landscape". The analysis by main components highlighted the preference of strains from flooded landscapes by a saline-alkaline environment, affecting during periods of drought, and strains from sandy hills landscape by a low medium in salts and acid soil, directly during period of high humidity resulting from previous floods.

Potentially pathogenic bacteria isolated from Paipa cheese and its susceptibility profiles to antibiotics and biocides

The objective of this work was to evaluate the microbiological quality of cheese produced by formal and informal micro-enterprises in Paipa, Colombia, to isolate potentially pathogenic bacteria and to determine their prevalence and resistance to antimicrobials such as antibiotics and biocides. Sixteen micro-enterprises of the seventy existing in the region were sampled during 3 years. Viable concentrations of aerobic mesophiles, total and fecal coliforms, Salmonella sp., Listeria monocytogenes, Staphylococcus sp., yeasts, and molds were determined. Seventy-three bacterial isolates were identified by 16S rRNA gene sequencing. The susceptibility of the isolates to antibiotics and biocides was determined. The results indicated that between 98 and 100% of the cheese samples (n = 48 samples) of formal and informal micro-enterprises presented populations of total and fecal coliforms and Staphylococcus sp. above the limits established by Colombian regulations and varied according to the micro-enterprise. The results also indicated that 56% of Staphylococcus isolates were S. aureus. L. monocytogenes was positive in 38% of the samples. Salmonella sp. was not detected. The coliforms that prevailed were Escherichia coli (25%), Citrobacter freundii (14%), and Proteus mirabilis (8%). All L. monocytogenes were sensitive to ampicillin but resistant to erythromycin and trimethoprim-sulfamethoxazole. S. aureus isolates were susceptible to most antibiotics, except tetracycline and erythromycin (7% resistance). Likewise, 30% of coliforms (n = 36) were multidrug-resistant to antibiotics but susceptible to biocides.

Hygiene Quality and Consumer Safety of Traditional Short- and Long-Ripened Cheeses from Poland

The aim of this study was the assessment of the microbiological quality of three types of traditional cheeses which are produced from raw and pasteurized cow’s milk. Two types of cheeses were of the short-ripened type, and one cheese was long-ripened. A microbial examination was conducted for the presence of Salmonella spp. and Listeria monocytogenes microorganisms and the count of aerobic, psychrotrophic, lactic acid bacteria, and coliform bacteria, as well as Escherichia coli, Enterobacteriaceae, Enterococcus spp., Staphylococcus spp., and yeasts. The examined cheeses did not fulfill the microbial criteria for food safety (presence of L. monocytogenes) and process hygiene (exceeded allowable levels of E. coli and coagulase-positive Staphylococcus). The levels of coliform bacteria, E. coli, and Enterobacteriaceae and the presence of Enterococcus faecalis determined in the three examined cheese types indicated that insufficient hygiene procedures were used during the production process. The results of the study indicate that the examined cheeses did not fulfill the microbial criteria for food safety and process hygiene according to the legislation. It is necessary to introduce correction procedures as indicated in the current report.