Biocontrol Agents Increase the Specific Rate of Patulin Production by Penicillium expansum but Decrease the Disease and Total Patulin Contamination of Apples

Synthetic fungicides are commonly employed for the control of postharvest diseases of fruits. However, due to health concerns about the use of these chemicals, alternative control methods including biocontrol based on antagonistic yeasts are gaining in popularity. In this study, we investigated the effects of two biocontrol yeasts, strain 3617 and strain LS11, on blue mold and patulin (PAT) contamination caused by strains PY and FS7 in artificially inoculated Fuji apples stored at 20°C for 9 days. To correlate the development of the strains in yeast-treated and untreated apples with PAT production, we quantified their biomass in the infected fruits using a recently published quantitative real-time polymerase chain reaction method based on specific primers for patF, a gene from that is involved in PAT biosynthesis. Both yeasts significantly reduced the disease incidence caused by the two strains of up to 5-7 days of incubation, and lowered their biomass and the progression of symptoms up to 9 days. Interestingly, both yeasts strains increased the rate of PAT production (expressed as ng patulin/μg fungal DNA) by the two pathogenic strains. Nevertheless, both biocontrol agents reduced the total PAT contamination, especially in the case of strain FS7, the higher PAT producer of the two tested strains. Comparing between the yeast strains, LS11 was more effective than 3617 for the control of .