Experimentating with pruno leads to 8 cases of botulism in Utah

The first case of food-related botulism recorded in the medical literature occurred in Germany in 1735 and was traced to uncooked fermented blood sausage. Food safety history guru (and pretty decent margarita recipe developer) Carl Custer pointed out in an IAFP workshop that botulism concerns (and regulatory responses) go back further than that. prunosweatshirtIn the 10th century, Emperor Leo VI of Byzantium prohibited the manufacture of blood sausage because of repeated illnesses leaving folks paralyzed and dying not too long after exposure. Botulism (derived from botulus, the latin word for sausage) is a pretty nasty old-world illness. Clostridium botulinum spores are fairly common in soil and can germinate and outgrow into vegetative cells in anaerobic, low acid conditions. A byproduct of the cells’ multiplication is the toxin.

Mrs. Kalisz, my family studies teacher warned of the dangers of botulism by showing a bulging can of beans. She didn’t mention anything about partially-fermented sausages, under processed home-canned food, packaged seafood, foil-wrapped baked potatoes – or a homemade prison alcohol called pruno.

To make pruno, a sugar source (like fruit acquired from a prison lunch) is put into in a bottle or bag, the naturally occurring yeast should convert the carbs into alcohol – creating some low-cost wine. If the sugar source is acidic fruit the low pH will suppress the germination of C. bot spores. If a potato (also full of carbs) is added by the amateur microbiologist it can raise the pH enough to allow for outgrowth. According to a paper published by Williams and colleagues in the Annals of Emergency Medicine, this is likely what happened in a 2011 botulism outbreak traced to a Utah prison.

Twelve prisoners consumed pruno, a homemade alcoholic beverage made from a mixture of ingredients in prison environments. Four drank pruno made without potato and did not Screen Shot 2013-12-14 at 4.07.42 PMdevelop botulism. Eight drank pruno made with potato, became symptomatic, and were hospitalized. The prune recipe involved in this outbreak (see right) was provided by patient 4, who reportedly had cooked this recipe approximately 20 times previously without a potato. The prisoner’s rationale behind using a potato was that he thought it would “accelerate fermentation,” and he was “experimenting.”

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About Ben Chapman

Dr. Ben Chapman is a professor and food safety extension specialist at North Carolina State University. As a teenager, a Saturday afternoon viewing of the classic cable movie, Outbreak, sparked his interest in pathogens and public health. With the goal of less foodborne illness, his group designs, implements, and evaluates food safety strategies, messages, and media from farm-to-fork. Through reality-based research, Chapman investigates behaviors and creates interventions aimed at amateur and professional food handlers, managers, and organizational decision-makers; the gate keepers of safe food. Ben co-hosts a biweekly podcast called Food Safety Talk and tries to further engage folks online through Instagram, Twitter, Facebook, YouTube and, maybe not surprisingly, Pinterest. Follow on Twitter @benjaminchapman.