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This study was performed as a follow-up to a study from 2013, to assess the impact of management interventions on aflatoxin incidence and levels in commercial groundnut products in Malawi. Sixtyseven samples of commercial groundnut products were analyzed for aflatoxin using a fluorometric method. Total aflatoxin levels ranged from 1.5 to 1200 lg/kg in raw groundnuts and 83-820 lg/kg in groundnut flour from vendors. In branded groundnut flour and peanut butter from supermarkets, aflatoxin levels ranged from 13 to 670 lg/kg and 1.3 to 180 lg/kg, respectively. About 93, 88, 78 and 72% of the samples analyzed contained aflatoxin levels above regulatory limit used in Malawi (3 lg/kg), EU (4 lg/kg), most developing countries (10 lg/kg), and the USA (20 lg/kg), respectively. Despite much effort, aflatoxin levels remain persistently high in commercial groundnut. Considering the difficulty of achieving an efficient government regulation system due to resource constraint, the authors recommend the promotion of a socially responsible groundnut processing industry that has consumer welfare as its central feature.

Aflatoxin contamination and biodeterioration were examined in 302 samples of dry cowpeas and pigeon peas that were randomly purchased from 9 districts of the Southern Region of Malawi during July and November 2015. Further, the impact of flotation/washing on aflatoxin levels on the pulses was elucidated. Aflatoxin analyses involved immunoaffinity column (IAC) clean-up and HPLC quantification with fluorescence detection (FLD) while legume biodeterioration assessments were done by visual inspection. Aflatoxins were frequently detected in cowpea (24%, max., 66 μg/kg) and pigeon pea (22%, max., 80 μg/kg) samples that were collected in the month of July. Lower aflatoxin incidence of 15% in cowpeas (max., 470 μg/kg) and 14% in pigeon peas (max., 377 μg/kg) was recorded in the November collection. Overall, aflatoxin levels were significantly higher in the pulses that were collected in November. However, there were no significant differences in the total aflatoxin (aflatoxin B (AFB) + AFB + AFG + AFG) levels between the two types of pulses. Remarkably, in 76.2% of the aflatoxin positive cowpea and in 41.7% of the aflatoxin positive pigeon pea samples, aflatoxin G concentration exceeded aflatoxin B Insect damage percentage averaged at 18.1 ± 18.2% (mean ± SD) in the cowpeas and 16.1 ± 19.4% in pigeon peas. Mean discolouration percentage (number of pulses) of the cowpeas and pigeon peas was found to be at 6.7 ± 4.9 and 8.7 ± 6.2%, respectively. Washing and discarding the buoyant fraction was highly efficient in reducing aflatoxin levels; only 5.2 ± 11.1% of the initial aflatoxin level was found in the cleaned samples. In conclusion, cowpeas and pigeon peas sold on the local market in Malawi may constitute a hazard especially if floatation/washing step is skipped.

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