Sir

The Commentary “A mess of red pottage” by two of us1 exposed the export from Australia of seeds from toxic common vetch (Vicia sativa) as a cheap substitute for the edible red lentil (Lens culinaris). Despite curbs to this trade in the wake of our article, the problem has recurred.

Dietary cyanoalanine neurotoxins from vetch accumulate in the brains and livers of pigs, rats and poultry. Effects on sulphur metabolism result in urinary excretion of cystathionine and accumulation of the non-functional glutathione analogue γ-glutamyl-β-cyanoalanyl-glycine. E. G. Brown2 pointed out that the genetic predisposition towards favism in Mediterranean communities makes this doubly unfortunate, because common vetch contains the favism toxin vicine.

After our Commentary was published, India and Egypt banned, and Saudi Arabia restricted, imports of vetch. The Victorian Weekly Times published articles entitled “Scientists cripple vetch industry” and “Vetch now unfit for humans to eat”. The A$18 million (US$11.7 million) market collapsed.

But last year we were alerted by the Sri Lankan Health Department of the problem's re-emergence. Unlabelled bags of split red vetch (240 tonnes) had been exported from Adelaide via Johor in Malaysia to Colombo. On arrival, the container documentation had changed from “red split vetch” to “red split lentils”. This event was extensively reported in the Sri Lankan Daily News3, but was ignored by the international media.

In April 1999, a report on Australian ABC radio 4 gave details of the multi-thousand tonne vetch/lentil substitution racket. The export price (A$340-400 per tonne) leaves no doubt that the bulk is sold for human consumption. Exports (in tonnes) from South Australia for the first four months of 1999 include: split vetch to Yemen (22) and United Arab Emirates (194); and ‘whole vetch’ to Argentina (10), Bangladesh (989), Belgium (187), Germany (63), Italy (149), Japan (120), Mexico (40), The Netherlands (124), Pakistan (903), The Philippines (22), Portugal (106), South Africa (42) and Taiwan (86).

From these data, and the sale of unlabelled split red vetch in the markets of Pakistan and Bangladesh, we conclude that either it is being split in the importing country or it is being split in Australia and exported labelled as whole vetch.

When cooked (without leaching) in mistake for red lentils, 1,000 tonnes of vetch gives ten million 100-g platefuls, each containing 0.5 g of cyanoalanine toxins. The harmful effects of vetch consumption in animals are known, but the effects on humans are not. Most at risk are malnourished vegetarian societies with sulphur-deficient diets.

To protect a valuable and expanding lentil industry, the Australian government moved swiftly (7 April 1999) to declare both vetch and lentils as prescribed grains. This means that inspection and phytosanitary certification are mandatory before export. Unfortunately, the financial rewards to exporters and importers are still too high to eliminate this dishonest trade.