Bongkrek

Bongkrek is a traditional Indonesian form of tempeh produced by fermenting coconut presscake or coconut milk residue with the mould Rhizopus oligosporus. It carries a notorious food-safety hazard: contamination with Pseudomonas cocovenenans (Burkholderia cocovenenans) can generate the heat-stable toxins bongkrekic acid and toxoflavin, causing frequently fatal food poisoning. Because the toxins survive cooking, prevention depends entirely on hygienic fermentation practice, use of pure starter cultures, and avoidance of the temperature and moisture conditions favouring the contaminant, making bongkrek a classic case study in fermented-food safety.