This discussion of contaminated breastmilk reminds me of a case a few years ago in our NICU of a mother with 26 week triplets whose babies all became infected with salmonella.  I believe it occurred a month or two after the babies were born.  Their blood and stool cultures were positive and they were isolated while an investigation was done.  Salmonella is not one of the usual hospital-acquired pathogens and it was a big red flag to Infection Control.  We did cultures of her breastmilk and none of the samples pumped at the NICU were positive.  Any positive samples were ones she had done at home.  Mother and father had stool and blood cultures done.  The infection control people even had us get a "clean catch" of breast milk after thorough cleansing and a prep of betadine to her breasts to make sure she didn't have it in her breasts(no S/S of mastitis)--and witnessed by an LC (She had made some odd comments noted by staff which made us think of ? Munchousen's).  Because the positive ones were done at home, we re-educated her on proper handwashing and cleaning/sterilization technique of pump parts, and asked to clean her kitchen area with bleach solution.  No further cultures were positive.  And her babies recovered nicely from salmonella, never getting very ill at all.  No other babies had positive cultures for salmonella.  Despite all of our "stuff" we did to check her and her breastmilk, this mother continued to provide her babies with milk until after discharge from the hospital.  Maureen Allen RN, BSN, IBCLC, Brigham and Women's Hospital, Boston, MA