Application of food preservatives on stored peanut pods to avoid grain fungal spoilage

PASSONE, M.A.; PONZIO, V.; NESCI, A.; BLUMA, R.; ETCHEVERRY, M.

Villa Carlos Paz, Córdoba, Argentina

Congreso; MYCO-GLOBE Advances in research on toxigenic fungi and mycotoxins in South America ensuring food and feed safety in a myco-globe context; 2006

Chulze, Dalcero, Resnik, Pacín

Impact of mixtures of food grade antioxidants (2(3)-tert butyl-4 hydroxyanisole-BHA, n-propyl p-hydroxybenzoato-PP and 2,6-di (tert-butyl)-p-cresol-BHT) on mycoflora from stored peanut pods was evaluated. Five experimental polyethylene big bags were used to store 200 kg of peanut pods from July to December 2004. Peanut pods were previously treated with a serial of antioxidants mixtures; BHA (10 mM); BHA-PP (10-10 mM); BHA-PP-BHT (10:5:10 mM) and BHA-PP-BHT (10:10:10 mM). A control big bag without antioxidants was made. Ten samples (250 g) were randomly collected at 30 days intervals using a sampling device. Temperature and humidity were monitored using a distance-reading thermometers and hygrometer. To determine fungal colonization on peanut pods, 50 g of milled pods were shaken with 450 ml of peptone / water and spread on dichloran / rose bengal / chloramphenicol (DRBC) and dichloran / glycerol 18% (DG18) media. The results were expressed as colony-forming units (CFUs) per g of peanut pods. The fungal genera were identified according to Pitt and Hocking (1997) and Samson et al. (2002). Mycological analyses of control samples showed predominance of Aspergillus spp., Penicillium spp. and Fusarium spp. populations. In minor grade, the genera isolated were Eurotium spp. Monascus spp., Mucor spp., Absidia spp., Rhizopus spp. and Alternaria spp. The general fungal count showed an increase from 1.1 x 103 to 1.2 x 105 UFC g-1, according temperature increased from 7.1 to 19.8°C, while the humidity to be maintained relatively constant, about of 8.2%. The samples treated showed count decreased (0.5 to 1 log) at two first sampling with BHA (10 mM), but the efficacy was not maintained during all storage period. Mixtures of BHA-PP (10:10 mM) significantly reduce general fungal growth (P=0.05) during three first months of storage. Only the genera Penicillium spp. and Aspergillus spp. showed count (103 CFU g-1). The best treatments were the mixtures BHA-PP-BHT (10:5:10 mM and 10:10:10 mM), which significantly reduced fungal contamination during the five months of storage. This study showed that the mixtures with BHA-PP-BHT were effective fungitoxicant during all storage period. These treatments avoid the growth of fungal propagules on the pods and could have practical value in the control of grain spoilage.   References Pitt, J.I. y Hocking, A.D. (ed.) (1997) Fungi and Food spoilage pp. 339-417. Samson, R.A., Hoekstra, E.S., Frisuad, J.C., Fitenborg, O. (2002) Introduction to food-and airborne fungi pp. 1-269.