A new in vitro method to detect growth and ochratoxin A-producing ability of multiple fungal species commonly found in food commodities.
The aim of the study was to develop a new screening method to detect growth and ochratoxin A (OTA) production by multiple fungi growing in a small quantity of culture media, using microtiter plates. Eight ochratoxigenic species were included in the study. The strains were inoculated in sterile 96-well flat-bottom microtiter plates containing Yeast Extract Sucrose broth and Czapek Yeast Extract broth and incubated at 25 °C. Growth was daily monitored by absorbance measurements for 4 days and extended to 7 and 10 days for Penicillium spp. The entire experiment was repeated twice on different days. On each sampling time, five of the seven replicate wells inoculated for each strain and culture media were randomly selected and the content of each well was removed, extracted and injected into the HPLC. No statistically significant differences were observed for absorbance and OTA values, neither between replicates nor between experiments. Quantifiable OTA levels were detected after 48 h of incubation in Aspergillus alliaceus, Aspergillus carbonarius and Aspergillus niger, after 72 h in Aspergillus flocculosus, Aspergillus steynii and Aspergillus westerdijkiae and after 7 days in Penicillium nordicum and Penicillium verrucosum. The method offers the necessary tools for a rapid detection of growth and OTA production avoiding the use of plate cultures and can be very useful when many fungal isolates need to be screened.
['Abarca|M L|ML|', 'Bragulat|M R|MR|', 'Cabañes|F J|FJ|']
D001230:Aspergillus D002851:Chromatography, High Pressure Liquid D005516:Food Microbiology D008828:Microbiological Techniques D016533:Mycological Typing Techniques D009793:Ochratoxins D010407:Penicillium
Screening method Ochratoxin A Penicillium Aspergillus Growth detection Inoculum standardization OTA-producing ability Spectrophotometric measurement of growth