Prestorage heat treatment reduces pathogenicity of Penicillium expansum in apple fruit

Abstract

Penicillium expansum is one of the main postharvest pathogens of apples in Israel. Heating apple fruit inoculated with P. expansum for 96 h at 38°C completely inhibited decay development. Fruit held for 24 h at 42°C or 12 h at 46°C had significantly reduced decay after an additional 14 days incubation at 20°C, compared with unheated inoculated control fruit. Mycelial growth and percentage spore germination in vitro were inversely proportional to length of time of exposure to various temperatures. The ET50 for spore germination was 42, 34 and 20 h at 38, 42 and 46°C, respectively, while the ET50 for mycelial growth was 48, 44 and 36 h at those temperatures. When Penicillium spores were incubated on crude extract prepared from the peel of apple fruits held 4 days at 38°C, germ tube elongation was significantly reduced, while the walls of the tubes were thicker, compared with germ tubes from spores incubated on crude extract prepared from peel of non‐heated fruit. The evidence presented here supports the hypothesis that the effect of heating on the decay of apples caused by P. expansum is not only the result of direct inhibition of fungal germination and growth by high temperature, but is also partly due to the formation of an inhibitory substance in the heated peel.

Synthesis, spectroscopic characterization, thermal stability and biological studies of mixed ligand complexes of gemifloxacin drug and 2,2′-bipyridine with some transition metals

“…The nutrient agar medium used for antibacterial study was 0.5 % peptone, 0.1 % beef extract, 0.2 % yeast extract, 0.5 % NaCl, and 1.5 % agar-agar. For antifungal study, Czapek Dox medium (3 % sucrose, 0.3 % NaNO 3 , 0.1 % K 2 HPO 4 , 0.05 % KCl, 0.001 % FeSO 4 , and 2 % agar-agar) was prepared [18], then cooled to 47°C and seeded with the tested microorganism. The actvity index equal inhibition diameter zone by test compound divided by inhibition diameter zone by standard (GMFX).…”

Synthesis and characterization and antibacterial activity of some new transition metal complexes with ciprofloxacin-imine

“…The tested microorganisms isolates were isolated from Egyptian soil and identified according to the standard mycological and bacteriological keys for identification of fungi and bacteria as stock cultures in the microbiology laboratory, Faculty of Science, Zagazig University. The nutrient agar medium for antibacterial was (0.5% peptone, 0.1% beef extract, 0.2% yeast extract, 0.5% NaCl and 1.5% Agar-Agar) and CZAPEKS Dox medium for antifungal (3% sucrose, 0.3% NaNO 3 , 0.1% K 2 HPO 4 , 0.05% KCl, 0.001% FeSO 4 , 2% AgarAgar) was prepared [21] and then cooled to 47…”

Spectroscopic, structural, thermal and antimicrobial studies of 4,6-bis (4-chlorophenyl)- 2-oxo-1,2-dihydropyridine-3-carbonitrile with some transition metals

“…The tested microorganisms isolates were isolated from Egyptian soil and identified according to the standard mycological and bacteriological keys for identification of fungi and bacteria as stock cultures in the microbiology laboratory, Faculty of Science, Zagazig University. The nutrient agar medium for antibacterial was (0.5% peptone, 0.1% beef extract, 0.2% yeast extract, 0.5% NaCl and 1.5% agar-agar) and Czapek Dox media for antifungal (3% sucrose, 0.3% NaNO 3 , 0.1% K 2 HPO 4 , 0.05% KCl, 0.001% FeSO 4 , 2% agar-agar) was prepared [9] and then cooled to 47…”