Alexey A. Burkin
All-Russia Research Institute of Veterinary Sanitation, Russia
Title: Optimal grain matrices for cyclopiazonic acid production by Penicillium griseofulvum
Submitted Date: 2021-05-17
Biography
Alexey A. Burkin, Ph.D., Principal Investigator of Mycotoxicology laboratory at All-Russian Research Institute for Veterinary Sanitation, Hygiene and Ecology (Moscow) from 1995. He is a specialist in the field of analytical immunochemistry and the author of more than 50 international scientific publications. His scientific work is devoted to monitoring of the mycotoxins in agricultural commodities and development of ELISA methods for mycotoxins, antibiotics and hormones determination.
Abstract
Cyclopiazonic acid (CPA) is a well-known mycotoxin with the dangerous ability to alter intracellular calcium flux in animals and a widely occurring contaminant of feed grasses and hay. Recently a 10-fold increase of the intensity of CPA biosynthesis by Penicillium griseofulvum Dierckx (= P. urticae Bainier) strains from mixed grass hay (Moscow region, 2013) on rice solid substrate in comparison to agar medium was revealed by the rapid screening procedure. The purpose of this study was to carry out the same test using the set of grain matrices. Each toxigenic strain was grown on watering polished rice (the control cultural matrice), oat flakes, corn and millet grits, barley and wheat groats in 15-ml vials in three replicates, and incubated for 7 days at 25°С without lightening. Fungal biomass samples were extracted with acetonitrile-water mixture (84:16 v/v) and CPA quantitation was made by ELISA with detection limit of 1.0 ng/ml. On rice toxin levels were equal to 10, 7 and 16 µg/g for the strains. Strain # 434/3 was inferior to the others in intensity of toxin biosynthesis on all substrates. On corn, millet and oat, the ratio of CPA amounts formed by # 201/4 and # 584/4 were reversed to those found on rice due to the mismatch of reactions of strains to the change of medium. The ratio of CPA level in the strains formed on barley and wheat were the same as on rice. The accumulation of toxin produced by both strains increased 1.5 times, and for # 434/3 it remained the same. On the wheat substrate, the intensity of production of all three strains increased 2.3, 2.0 and 1.75 times. Thus, according to the received data, wheat and barley could be considered as the most appropriate cereal substrates for laboratory assessment of producing potential of Penicillium griseofulvum.
Saba Kobakhidze
Division of Risk Assessment, Scientific-Research Center of Agriculture, Georgia.
Title: Positive Correlation between the Concentrations of Escherichia coli and Coliforms in Drinking Water Samples Collected Across Different Regions of Georgia
Submitted Date: 2021-02-09
Biography
Saba Kobakhidze has completed his Master Degree at the age of 27 years from the Tbilisi Medical State University. He is the senior Public Health specialist in the Risk Assessment Division of the Scientific-Research Center of Agriculture, conducting actively risk assessment in the areas of food safety. His PhD research is focused on the molecular epidemiology of some important foodborne pathogens. In addition, as a former specialist of the National Food Agency, he provides the G.Natadze Scientific-Research Institute of Sanitary, Hygiene and Medical Ecology with expertise in food safety testing and other practices
Abstract
Total coliforms and Escherichia coli are the important indicators of microbial contamination of drinking water worldwide. Public health risk assessment studies (Environ Sci Technol. 2015 Aug 18;49(16):10019-27), focusing on microbial contamination of drinking water, demonstrated the tendency of estimated risk reaching nearly zero, and vice versa, nearly tripling when changing the E. coli-to-total coliform ratios to their lower 2.5th versus 97.5th percentiles respectively. As part of the risk assessment study, in this regard, we determined and assessed the ratios of colony forming units (CFUs) of E. coli and total coliforms in tap water samples (a total of 250 samples) collected during 2017-2019 in Georgia. The non-parametric Spearman’s rho coefficient was applied to detect the correlation between the CFU counts of E. coli and those of total coliforms per each water sample (100 mL), with a probability of less than 0.05 considered as statistically significant. The above calculations were performed using SPSS (Version 23.0, Armonk, NY). These analyses revealed a statistically significant positive correlation between the CFU/100 mL counts of the above organisms (Spearman’s rho 0.733; p<0.001), indicating that the total coliforms concentration can be a predictive variable for up to 54% of the concentration variations of E. coli in drinking water. While for validation purposes a significantly larger number of samples need to be analyzed, the statistical data, obtained in this pilot study, can be useful for predictive modeling in quantitative microbial risk assessments associated with tap water contamination in Georgia.
