Human botulism is a severe disease caused by toxins called botulinum neurotoxins (BoNTs). They are mainly produced by bacteria of the species Clostridium (C.) botulinum in food and ingested with food. The disease usually leads to specific neurological disorders, e.g. visual disturbances, dry mouth, speech and swallowing disorders, and can be fatal. Animals can also fall ill if they ingest BoNTs with their feed. Among farm animals, cattle are primarily affected. Against this background, the German Federal Institute for Risk Assessment (BfR) has assessed the risk of contracting botulism in Germany from the consumption of milk and dairy products if milk from healthy cows is processed that originates from a farm with acute cases of botulism in the dairy herd. In the European Union, raw milk must come from animals that are in a good general state of health. They must not show any signs of disease that might result in the contamination of milk. However, on dairy farms with acute cases of botulism, large quantities of C. botulinum spores may be excreted in the faeces of healthy as well as sick cattle and get into the tank milk when the healthy cows are milked. However, dilution effects during transport and during processing in the dairy would considerably reduce the spore content. In addition, germination of the spores and the formation of BoNTs is not to be expected in dairy products that are stored refrigerated or frozen (e.g. pasteurised milk, milk ice cream), are highly acidified (sour milk products) or have a low water content (butter, milk powder). That’s why cases of botulism from the consumption of these dairy products are very unlikely. Furthermore, the spores of C. botulinum can be completely killed by heating to 121 degrees Celsius for at least three minutes or comparable heat treatment processes (e.g. sterilisation, ultra-high temperature). Ultra-high temperature (UHT) processing involves a short-time heating to a temperature of at least 135 degrees Celsius. Therefore, no cases of botulism are to be expected from the consumption of UHT treated milk and dairy products made from it. So far, no human cases of botulism associated with the consumption of milk and dairy products have been reported in Germany. Individual outbreaks and cases of botulism have occurred worldwide after the consumption of milk and dairy products. However, they were at least partly caused by subsequent contamination and/or faulty storage. Therefore, the BfR assesses the risk of contracting botulism in Germany from the consumption of milk and dairy products as very low. This assessment also applies if milk from healthy cows is processed that originates from a farm with acute cases of botulism in the dairy herd. To protect against botulism, consumers should not store raw milk unrefrigerated, even for the production of dairy products. Furthermore, to protect against food-borne infections, raw farm-gate milk should be boiled before consumption.
Date Published : 20 October 2022
Futher Information : https://www.bfr.bund.de/cm/349/acute-botulism-in-german-dairy-herds.pdf
