Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania.

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 microg kg(-1) (median = 363 microg kg(-1)) and in 15% exceeded 1000 microg kg(-1); the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 microg kg(-1) (median = 24 microg kg(-1)). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 microg kg(-1)). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies.

Evaluation of nutritive value and functional qualities of sorghum subjected to different traditional processing methods.

Sorghum (Sorghum bicolar L. Moench), a staple food in many parts of the world, is underutilised compared to its potential due to inherent problems. A study was conducted to evaluate the effect of different traditional processing methods on the nutritional and functional qualities of sorghum. The review of literature established the main causes of the low level of sorghum utilisation to be low nutritional and inferior organoleptic qualities. It was further established that traditional processing methods, such as germination and fermentation, can promote its utilisation. Three processing methods, namely germination (G), fermentation (F), and germination combined with fermentation (GF), were used to prepare feeds from two sorghum varieties, Tegemeo and Udo. Evaluation of the feed qualities in terms of acceptability, retention, feed efficiency ratio (FER) and protein efficiency ratio (PER), using weanling rats was carried out and compared to the untreated one which served as control. An element of functional properties was assessed in terms of diastatic power (DP). Regarding feed intake, there was no significant difference between the feeds. Body retention for Tegemeo variety was higher than that for Udo. FER ranged from 0.019 +/- 0.015 to 0.095 +/- 0.015, PER ranged from 0.113 +/- 0.089 to 0.703 +/- 0.111 and diastatic power from 15.99 +/- 1.20 to 114.58 +/- 0.95. In all the three cases, germinated feeds had the highest values and were therefore considered of higher nutritional value. It was therefore concluded that germination was superior to the other processing methods in improving the nutritional and functional qualities of sorghum.