Control of spoilage and ochratoxin A (OTA) production in moist grain for animal feed using tie biocontrol agent Pichia anomala

摘要

Pichia anomala has been found to reduce mould growth and ochratoxin A (OTA) production. The major hurdle in production of commercial biocontrol agents (BCAs) has been the lack of production of appropriate formulations. Of particular importance is theconservation of viability and ecological competence after application. With this in mind, studies were conducted to develop formulations of P. anomala which would have these attributes. Studies with fluidised bed-drying examined several additives for conservation of viability and showed that cotton seed flour + skimmed milk was the best treatment. Yeast cell osmoprotection was also employed. The biocontrol efficacy of formulated P. anomala cells was tested at the laboratory scale and results showed thatthey inhibited mould growth and OTA production. Formulation additives were found to have no adverse effect on mould growth and OTA production. Furthermore, modified yeast cells with increased levels of trehalose and arabitol gave similar efficacy as fresh cells. A subsequent pilot scale study, using malfunctioning airtight silos containing moist grain, showed that addition of fresh cells or formulated P. anomala cells both effectively controlled Penicillium roqueforti.