Minimum infective dose of shigella is :

Ans: B (10-100) "It has been shown that 106 pathogenic vibrios administered to fasting normochlorhydric volunteers, without food or buffer, did not produce infection, while the same dose along with food or sodium bicarbonate caused dinical cholera in 80-100 % of them"- Ananthanarayan 9th/307"Shigella cause bacillary dysentery. Infection occurs by ingestion. The minimum infective dose is low- as few as 10-100 bacilli are capable of initiating the disease, probably because they survive gastric acidity better than other enterobacteria"- Ananthanarayan 9th/287"Enteric fever(salmonella): In human volunteer experiments, the ID 50(infective dose) was found to be about 103 to 106 bacilli - Ananthanarayan 9th/295