Control of Aspergillus carbonarius and Aspergillus niger growth using phenolic antioxidants

BARBERIS C.,; ASILI R.,; ASTORECA A.,; FERNÁNDEZ- JURI M.G.,; MAGNOLI C.E.,; DALCERO A.M.

Estambul, Rusia

Congreso; XII International IUPAC Symposium on Mycotoxins and Phycotoxins; 2007

Peanut is an important food commodity in Argentina. Colonization of peanuts by Aspergillus niger aggregate has often resulted in ochratoxin A accumulation. This study was carried out to determine the efficacy of phenolic antioxidants butylated hydroxyanisole (BHA) and propilparaben (PP) under different interacting water activity (aW) and temperature regimes on the lag phase and growth rate by A.carbonarius and A niger. In this experiment A. carbonarius (ANMG) (AC2034) and A. niger (AN1911) (ANM42) were used. Peanut meal extract agar (PMEA) was prepared at 2%. The aW of the medium was adjusted to 0.995, 0.98 and 0.93 with glycerol, BHA and PP at 1, 5, 10 and 20 mM were added to the basic medium. The plates were centrally needle-inoculated and incubated for 30 days at 25ºC. Radial growth rates (mm/dia) were calculated as the slope of the linear regression obtained from plotting the colony radius of the replicates against time. In the control treatments there was a parallelism between the increment of lag phase and the reduction of growth rate when aW decreased for all isolated. The antioxidants showed a further increase in the lag phase at higher concentrations. Interactions between aW and antioxidants reduced the growth rate of all the strains. At all aW levels, BHA at 20 mM and PP at 5mM completely inhibited growth. At 1mM and 0.995 or 0.98 aW, the antioxidants were relatively ineffective. The use of antioxidants could be a good strategy to diminish the entry of ochratoxin A into the human food chain.