HIGH-LEVELS OF GLYCOALKALOIDS IN THE ESTABLISHED SWEDISH POTATO VARIETY MAGNUM-BONUM

In 1986, potentially toxic levels of the glycoalkaloids alpha-solanine and alpha-chaconine were unexpectedly found in tubers of the established Swedish consumer potato variety Magnum Bonum, leading to the imposition of a conditional sales ban on such potatoes. The combined amounts of alpha-solanine and alpha-chaconine in more than 300 commercial lots of Magnum Bonum potatoes analysed as a consequence of the ban ranged from 61 to 665 mg kg(-1) fresh weight with an average of 254 mg kg(-1). Sixty-six percent of the samples exceeded a temporary maximum residue limit of 200 mg kg(-1), 8% were above 400 mg kg(-1). Peeling did not significantly remove the glycoalkaloids in tubers with a high content. The occasional glycoalkaloid elevation was initially attributed to the unusually cold and rainy conditions during the late part of the season in 1986, but subsequent investigations have failed to confirm this hypothesis. Varietal characteristics are likely to have been involved since most other common Swedish varieties seemed to have had normal glycoalkaloid levels in 1986. There were no indications of serious or widespread adverse health effects in consumers due to the high glycoalkaloid levels, although there was circumstantial evidence that a few cases of temporary gastrointestinal disturbances were caused by consumption of Magnum Bonum potatoes with glycoalkaloid concentrations in the range 310-1000 mg kg(-1).