Mould growth and mycotoxin production intraspecific variability: a study with Penicillium expansum isolates

DAIANA GARCIA; ANTONIO J. RAMOS; VICENTE SANCHIS; SONIA MARÍN

Congreso; International Congress of Postharvest Pathology; 2011

Mycotoxin contamination of food products is an important health hazard of a growing interest around the world. Penicillium expansum has been considered the main in patulin production in apples and pears. Generally, fruits are stored at suboptimal conditions for mould growth and this situation could influence on the intra-species variability in their growth capability and mycotoxin production. Generally, foods and feeds are stored at suboptimal conditions for mould growth. Different environmental factors, like temperature, activity water (aw), pH, etc., could influence on the variability intra-species in their growth capability and mycotoxin production, and this might be increased when marginal conditions exist. The aim of this research was to assess the impact of suboptimal environmental conditions on the intra-specific variability of P. expansum and patulin production using seventy nine isolates of this mould. Petri dishes with Apple Concentrate Agar Medium (ACAM) medium were inoculated centrally and two temperature conditions were tested: 20ºC as a temperature near to optimal and 1 ºC as a suboptimal temperature, normally used for fruit storage. For each condition, 10 Petri dishes were inoculated, and colony growth and patulin production was measured along time. ANOVA revealed significant differences among growth rate (μ) and lag phase (λ) within the seventy nine assayed isolates. Coefficients of variation revealed a wider dispersion of μ (mm/day) and λ (days) at 1ºC compared to 20ºC. There were significant differences (p