Thank you for your interest in Organic Housekeeping!
When our son was an infant, almost 22 years ago, we were having diaper rash trouble, our doctor told us to use vinegar water in the diaper pail, and then to put vinegar in the rinse water. The diaper rash disappeared. Vinegar not only kills bacteria, it also helps rinse detergent and soap residues out of the diapers. Vinegar has a very long history of use as an antibacterial agent: pickling is the process of using vinegar to preserve food by preventing bacterial growth.
Researchers are investigating the bactericidal effects of vinegar. Here's a short exerpt from an article the Journal of Food Protection:
J Food Prot, 1998 Aug, 61(8), 953 - 9
"Antibacterial action of vinegar against food-borne pathogenic bacteria including Escherichia coli O157:H7; Entani E et al.; The bacteriostatic and bactericidal actions of vinegar on food-borne pathogenic bacteria including enterohemorrhagic E . coli (EHEC) O157:H7 were examined. The growth of all strains evaluated was inhibited with a 0.1% concentration of acetic acid in the vinegar. This inhibition was generally increased in the presence of sodium chloride or glucose. There was almost no difference in sensitivity to the bacteriostatic action of vinegar among the strains of pathogenic E. coli. Vinegar had a bactericidal effect on food-borne pathogenic bacteria including EHEC O157:H7. This action against EHEC O157:H7 was synergically enhanced by sodium chloride but was attenuated with glucose. For EHEC strains (O157:H7, O26:H11, O111:HNM) the difference in the inactivation rate due to vinegar among strains used was small, although an enteropathogenic E. coli (EPEC) O111:K58:H- strain was more sensitive, being more quickly killed compared with EHEC strains. The inactivation rate due to vinegar was constant irrespective of inoculum size. However, it differed greatly depending on growth phase of the cells, where logarithmic growth phase cells were more sensitive and easily killed than stationary phase cells. The bactericidal activity of vinegar increased with the temperature. Various conditions for bactericidal effects on EHEC O157:H7 were examined by the multiparametric analysis of five factors: acetic acid concentration in the vinegar, sodium chloride concentration, temperature, incubation time, and viable cell number . The combined use of vinegar and sodium chloride, with use of an appropriate treatment temperature, was found to be markedly effective for the prevention of bacterial food poisoning."
A solution of 1 part white vinegar to two parts distilled water is recommended by many sources for cleaning home-medical equipment such as nebulizers, tracheotomy equipment, and c-pap equipment. This type of equipment must be free of bacteria so the patient does not contract a bacterial lung disease. Chlorine bleach would be a very, very dangerous thing to use on this type of equipment!
Please bear in mind that E. coli does not form spores and is not resistant to dessication; a dry E. coli is a dead E. coli. Killing the bacteria in the diaper pail and in the wash water simply makes the diaper handling safer for you during those stages. Once the diapers have been fully dried in the clothes dryer or on the clothesline, there will be no live E. coli bacteria on them.