It would be better to avoid using zucchini, pumpkins and cucumbers if they taste bitter. Because the bitter substances can have unpleasant or life-threatening effects.
The members of the cucurbitaceae family include zucchini, pumpkins and cucumbers. All cucurbits can produce so-called cucurbitacines: bitter substances that have been bred out of the edible varieties. And for good reason, because cucurbitacines not only taste unpleasantly bitter and metallic, but also act as a cytotoxin.
Possible symptoms of cucurbitacin consumption
Anyone who consumes cucurbitacine must expect food poisoning (which may be severe). This is especially associated with gastrointestinal discomfort such as:
Such symptoms occur within a few hours of consumption (even small amounts). Depending on the dose, the reactions to cucurbitacins can also lead to life-threatening circulatory failure. This is especially true for children, the elderly and people who are already weakened, for example, by previous illnesses.
Fortunately, life-threatening cases rarely happen – presumably because the bitterness usually tastes so unpleasant that most people do not continue the dish on their own.
Danger from your own garden
The property for bitter substances is on a single gene in the cucurbits. In the edible, not bitter varieties this is inactive, but still present. This can be a risk if you plant zucchini, pumpkins and cucumbers yourself and also use your own seed. Then it may happen that there are some specimens among the fruits where …
… by spontaneous mutation the Bitterstoff gene was switched on again.
… there has been an unplanned fertilization with wild varieties that are not intended for consumption (e.g., ornamental squash).
… after a heat wave or dry season the bittern gene was switched on again as a stress reaction.