Abstract

The antifungal activity of the Polyhexamethylene-guanidine hydrochloride (PHMGH)-based disinfectant against fungi isolated from papaya fruit was evaluated. The aim of this work was to show that the PHMGH can be used as a disinfectant for papaya preservation. Thirty one strains of fungi were isolated as Mucor sp., Botrytis sp., Penicillium sp., Geotrichum sp., Aspergillus sp. and Colletotrichum sp. Mucor sp. was the most isolated with a frequency of 52.77% followed by Botrytis (47.22%), Aspergillus and Penicillium (8.33%), Colletotrichum (5.56%) then, Geotrichum (2.78%). The antifungal activity of the PHMGH was tested through the determination of the minimal inhibitory concentrations (MICs) and the minimal fungicidal concentrations (MFCs). All the strains tested were sensitive to the disinfectant. However, the activity of PHMGH varies according to the strain tested. The values of the MIC and the MFC were between <0.01 and 1.9 mg/ mL. Aspergillus sp. was the least susceptible fungi with a MIC and MFC of 1.9 mg/ mL whereas the most sensitive to PHMGH were the genera Botrytis and Colletotrichum with a MIC <0.01 mg/ mL. No matter the strains of fungi studied, the MIC and MFC values were equal. The PHMGH could therefore be considered as a fungicidal agent that could serve for the preservation of papaya fruit after harvesting.

Key words: Antifungal activity, minimum inhibitory concentrations (MICs), minimum fungicidal concentrations (MFCs), papaya preservation, polyhexamethylene-guanidine hydrochloride.