Eficacia y estabilidad del proceso de amonificación como tecnología de descontaminación de aflatoxina B1 en arroz (Oriza sativa) / Efficacy and stability of ammoniation process as aflatoxin B1 decontamination technology in rice

Rice, a cereal widely used in Venezuela for human and animal nutrition, is susceptible to aflatoxin contamination in the field and during storage. Therefore, the goal of this research was the evaluation of the efficacy and permanence of the ammoniation process through high pressure/high temperature (HP/HT) and atmospheric pressure/moderate temperature (AP/MT) conditions applied to rice samples artificially contaminated with aflatoxin B1. For this purpose a 2k design was drawn up considering the temperature, the rice moisture and the process time as variables. Under both sets of conditions, aflatoxin B1 concentration was reduced in a range of 90 per cent to 100 per cent. After in vitro stomach digestion simulation, toxin reversion ranged from 0 per cent to 19 per cent. In conclusion, the process efficacy and permanence were achieved through the use of high temperature and long process time for both sets of conditions (HP/HT and AP/MT), respectively.

[Determination of deoxynivalenol (DON) in wheat, barley and corn and its relationship with the levels of total molds, Fusarium spp., colonization percentage and water activity]. / Determinación de deoxinivalenol (DON) en trigo, cebada y maíz y su relación con los niveles de mohos totales, Fusarium spp., porcentaje de colonización y actividad de agua.

Fifty samples of cereals including 30 of wheat (10 of wheat hard red spring), 10 of wheat soft red winter and 10 of wheat durum ámber), 10 of barley and 10 of corn (5 of white corn and 5 of yellow corn) were analyzed to detect and determine by the TLC method, the quantity of deoxynivalenol levels, which is a toxic secondary metabolite produced by Fusarium species. The aw of samples and the internal and external micoflora and Fusarium spp. levels were also investigated. Results showed that the highest grade of infection (12-80%), and the highest count of total molds (3.9 Log UFC/g) were detected in wheat samples, while the highest levels of Fusarium spp. (2.3 Log UFC/g) were detected in white corn. Deoxynivalenol was found in the wheat and barley samples but not in corn. The wheat red winter soft samples showed the highest levels of deoxynivalenol (3.2 ug/g) which is over the limit levels accepted by the FDA. Correlation was not found among count of total molds, Fusarium spp., infestation grade, aw, and deoxynivalenol levels. These results suggest that it is necessary to exert measures to avoid and to control the importation of contaminated cereals with DON levels higher to those allowed.