EFFECTIVENESS OF CARBON DIOXIDE AND OZONE IN REDACTION OF PEANUT SEED INFECTION WITH ASPERGILLUS NIGER AND PRODUCTION OF OCHRATOXIN A IN LABORATORY CONDITION

Abstract

This study was conducted at the Plant Protection Department /College of Agriculture Engineering Science -University of Baghdad in 2016- 2017. The objective of the study was to investigate the efficiency of the CO2 and O3 gases in radial growth inhibition, dry biomass and Ochratoxin A reduction of the Aspergillus niger isolate under laboratory conditions in addition to evaluate the effective of both gases in the storage of peanut seeds with free fungi growth and ochratoxin A contaminated . Results revealed that exposing the isolate colony grown on PDA to CO2 and O3 at a concentration of 4 liter/minute for 60 minutes inhibited the redial growth rate by 28.33% and 20.0% respectively. Both gases reduced the dry biomass for fungus isolate grown on potato sucrose broth (PSB) at concentration (flue rate) of 4L/min for 60 minutes up to of 0.017 g which compared to 0.71 g for the control treatment when exposed to both gases for 60 min. No bright spot was shown when the fungi isolate grown on the yeast extract sucrose broth were exposed each to both gases at different concentrations and exposure time which indicate the effectiveness of the treatments in removing and degrading Ochratoxin A at the laboratory conditions, when compared to the standard Ochratoxin A spot. It is found that the treatment of 1 Kg of peanuts contaminated with 1 ml of the A.niger spore suspension at concentration of 175 × 107 spore/ml in a tightly plastic containers with CO2 and O3 separately at concentration of 1Lmin for 5 minutes and 4 Lmin for 60 minutes resulted in significant reduction by 87 – 98% for O3 and Co2 treatments respectively detected by HPLC compared to control treatment after two months of storage at incubator conditions (25±2°C). Key words: