Stuff.co.nz: New Zealanders were surprised to learn that those forces for good in human health – lettuce and carrots – were identified as a common link in the outbreak of Yersinia infections that made at least 220 people sick and sent 70 to hospital in 2014. [T]he source of the New Zealand outbreak was never proven, and this was mainly because of the difficulty of tracing all the ingredients of a mixed salad.