South Australia
May 2, 2011
Tests on lentils from the 2010/2011 harvest, arranged by SARDI and funded by SAGIT have shown that they were free of mycotoxins posing no detectable safety risk as human food or stockfeed.
The South Australian lentil harvest in 2010/2011 was difficult due to rain, leading to concerns regarding grain quality at silo receival. Quality was compromised by a number of factors including weather staining, disease (Ascochyta and Botrytis) staining, unfilled grain and wrinkled seed coat. The rain events also raised concerns that the grain may have become infected with field moulds (e.g. Alternaria spp, Fusarium spp., Aspergillus spp.) which in turn could produce toxins in the grain that may affect stock and humans.
Lentils are graded for these quality traits at silos with a visual appraisal. However, subjective testing often cannot distinguish between field mould and the other traits that cause seed staining, making the accuracy of grading difficult.
This pilot survey of 28 SA lentil samples aimed to test for seed quality defects including the presence of hazardous mycotoxins in samples either rejected at receival or appearing to be severely affected based on visual examination. This approach was biased to ensure that seed samples where mycotoxins were most likely to be detected were selected.
The samples from 2010/2011 harvest all were found to be free of mycotoxins, posing no detectable risk as human food or stockfeed.
Of the potential toxin producing fungi, Fusarium species. were detected at varying levels on the grain but not Aspergillus species. Of thelentil crop pathogens, Ascochyta blight was detected on many samples, however, no Botrytis infection was detected.
From these results it was often difficult to distinguish between field mould, disease and weather damage on the seed - see Figures 1 & 2.
A more objective testing regime for lentils is required to distinguish between disease stained grain, wrinkled seed coat and weather stained grain. The Pulse Breeding Australia lentil program targets improving seed quality. A new project funded by GRDC is exploring the opportunity of using digital imaging analysis to objectively and rapidly characterise lentil quality attributes including down graded seed.
Fig 1. Field mould on lentil grain
Fig 2. Unfilled grain (Left), Ascochyta stain (Centre), disease and/or field mould (Right)
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