Citrobacter freundii lives in pigs' guts and is also potentially lethal. If manure is pasteurised, or if you properly cook contaminated food, then the organism is killed. The problem is to guarantee that this is done. Oversights do occur. Two outbreaks of E coli 0157 in the US were traced to organic strawberries and lettuce.
Organic farmers use sulphur as a weak pesticide.
But sulphur contains lead, a known danger. What is not known is how much of the lead is transferred to the food we eat. Similarly, organic farmers are allowed to spray crops with bacterial spores to act as a general-purpose insecticide. But earlier this year these spores were found to cause serious, often fatal, lung infections in mice, and to infect wounds and damage human cells in culture. Some people suggest that this technique should be curtailed until further investigations are carried out.