Control of Penicillium martensii Development and Penicillic Acid Production by Atmospheric Gases and Temperatures

The effects of various gaseous environments and temperatures on development ofPenicillium martensii NRRL 3612 and production of penicillic acid (PA) were determined. Accumulation of PA in mold-inoculated corn was measured following incubation under air; 20% CO2 , 20% O2 , 60% N2 ; 40% CO2 , 20% O2 , 40% N2 ; and 60% CO2 , 20% O2 , 20% N2 . Although reduced temperature initially inhibited PA production, at the end of the trial the largest quantity of PA (120 μg/g of corn) was found in air-incubated corn at the lowest test temperature (5 C). Atmospheres enriched with 60% CO2 reduced PA accumulation below a detectable level at 5 and 10 C after a 4-week incubation period. Spore germination tests were carried out in a liquid growth medium incubated for 16 hr under several test conditions. Germ tube outgrowth at 30 C ranged from 36% in air to 2% in 60% CO2 , whereas no germination was observed in CO2 -enriched gases at 10 C. When spore respiration rates were measured in air and O2 in a liquid growth medium, complete removal of CO2 from the reaction atmosphere did not reduce O2 uptake.