SummaryAn outbreak of ropy milk in bottled pastuerized milk was traced to Bact. aerogenes types I and IT and possibly Alkaligenes species gaining access through the filler bowl from some of the washed milk bottles. Most of the bottles were of low count by the standard rinse technique, but the majority were capable of producing rope when filled with sterile milk. The standard rinse technique seems inadequate for the detection of this kind of contamination.