Ochratoxin A and citrinin loads in stored wheat grains: impact of grain dust and possible prediction using ergosterol measurement

Emmanuel Kossi Tangni (1) , Luc Pussemier (2)

1 Quality and Safety
2 Quality and Safety

Crop storage should be done under hygienic conditions for safe products, but sometimes grain dust settled from the previous storage may be left and incorporated to the following stored grains. This paper describes the results obtained using a lab model developed in order to assess the impact of grain dust incorporation for its direct contribution as a contaminant but also as an inoculum in stored grainwheat. Samples of settled grain dust (4) released from Belgian grain storages were collected and analyzed by HPLC for ergosterol, ochratoxin A (OTA) and citrinin (CIT) contents. For OTA and for ergosterol, there was a high degree of variability in concentrations found in the 4 dust samples (from 17.3 to 318 ng g-1 and from 39 to 823 ug g-1, respectively) whilst for CIT, the range was less important (from 137 to 344 ng g-1). Incorporation of grain dust in wheat grain storage contributes to the increase of the concentrations of mycotoxins in stored grain. Dust acts as a contaminant and as an inoculum. According to these two ways, patterns of mycotoxin generation vary with the nature of the mycotoxin, the mycotoxigenic potential of dust and the water activity moisture content of in wheat. OTA and CIT show a very versatile image when considering the amounts of toxins produced under the selected experimental conditions. The development of a robust tool to forecast the mycotoxigenicity of dust was based on the determination of ergosterol content as a general marker of fungal biomass. Present results suggest that this predictive tool could only be valid for predicting the contamination level of CIT and OTA at reasonable moisture content (14-20 %). Potential risk of having highly contaminated batches from stock to stock may thus occur and this paper discusses possible pathways leading to OTA and CIT contamination either under wet or dry storage conditions. We therefore, recommend taking precautionary measures not only by controlling and maintaining moisture at a reasonable level during storage of the raw materials but also by paying more attention to the cleaning of the stores before loading in the new harvests Key words: Cereals, Storage, Grain dusts, Fungal growth, Ergosterol, Mycotoxins

Mots clés: Life Sciences

Emmanuel Kossi Tangni, Luc Pussemier. Ochratoxin A and citrinin loads in stored wheat grains: impact of grain dust and possible prediction using ergosterol measurement. Food Additives and Contaminants, 2006, 23 (02), pp.181. ⟨10.1080/02652030500391911⟩. ⟨hal-00577565⟩