Effect of modified atmosphere packaging at abuse temperature on the growth of Penicillium aurantiogriseum isolated from fresh filled pasta

The effect of reduced O2 and elevated CO2 modified atmospheres (MAP) and abuse temperature (15 °C) on the growth of Penicillium aurantiogriseum were evaluated. Measured colony diameter growth curves are fitted to estimate the growth rate (μ) and lag phase (L) of the fungus. The colony growth rate was modelled by Baranyi and Roberts (Int. J. Food Microbiol. 23 (1994) 277) function. A good correlation between the experimental data and the model prediction was obtained, the regression coefficients (r2) were 0.99. P. aurantiogriseum grew in atmospheres containing 30% and 50% CO2, but the growth rate decreased and lag phase increased compared with growth in air. No fungal growth was observed for up to 550 h of incubation at 15 °C when samples were packaged in atmospheres with CO2 concentrations higher than 70%. The growth rate and lag phase was modelled as function of CO2 concentrations using a polynomial model equation. The estimations of growth rate and lag phase were in excellent agreement to the experimental results (image; image; image). The time to reach a colony diameter of 3 mm was also calculated.