An extension of the coconut cream agar method to screen Penicillium citrinum isolates for citrinin production

A simple and rapid screening method was developed for the detection of citrinin in fungal cultures using Coconut Cream Agar (CCA) described previously for detecting aflatoxin and ochratoxin A. Fifteen isolates of Penicillium citrinum were inoculated onto CCA and incubated at 25 and 30°C for 10 days. All isolates produced a distinct yellow green fluorescence on CCA when the reverse side of the agar plates were viewed under long wavelength UV light. Detection was optimal at 25°C after four to 5 days of incubation. Isolates positive by the CCA method also tested positive for citrinin production by the TLC agar plug method after growth on CCA, Czapek yeast extract agar and yeast extract sucrose agar. Control cultures were negative by both methods, indicating that the CCA Petri dish method was suitable for screening cultures for citrinin production. Significance and Impact of the Study Citrinin is a nephrotoxic mycotoxin produced by several species belonging to the genera Aspergillus, Penicillium and Monascus. A simple and rapid screening method was developed for screening citrinin in fungal cultures using Coconut Cream Agar (CCA) described previously. This method provides a direct indication of the presence of citrinin after four to 5 days incubation at 25°C. The method has been tested using fifteen isolates of P. citrinum and appears to be suitable for large scale screening of cultures for citrinin production. Significance and Impact of the Study: Citrinin is a nephrotoxic mycotoxin produced by several species belonging to the genera Aspergillus, Penicillium and Monascus. A simple and rapid screening method was developed for screening citrinin in fungal cultures using Coconut Cream Agar (CCA) described previously. This method provides a direct indication of the presence of citrinin after four to 5 days incubation at 25°C. The method has been tested using fifteen isolates of P. citrinum and appears to be suitable for large scale screening of cultures for citrinin production.