E-Coli Source Was Poor Hygiene?

E-Coli source needle in hay stack compass tracing back? Contamination source was poor hygiene at restaurant in Lübeck? Apparently at least 17 people infected with virile E-Coli had eaten there? Such a high number suspicious severe cases means huge contamination? Probably occurred somewhere anywhere from farm to fork? Source origin point cleaning, packaging, transport, at wholesalers, or any retailers... anywhere along supply food chain? Quite unprofessional then to point bugs on the run gun... at Spanish cucumbers or German bean sprouts... instead suspect source... contamination may have been poor hygiene either at a farm in transit, in a shop or food outlet?