We Soak our Bottles and Tube Feeder
"We don't have to wash our bottles and tube feeder because we soak them every week."
This comment was meant to excuse the calf care person from washing bottles and tube feeder after every use. She "rinses" her equipment after each use in hot water during the week. At the end of the week all this stuff goes into this sink to "soak clean."
She uses enough household bleach to create a 500 parts per million(ppm) concentration of the sodium hypochlorite ingredient. See Bleach Dilution Table.
Two problems here:
1. Not washing after each use allows the build up of biofilms on the inside surfaces of both bottles and tube feeder. Once these begin to coat these surfaces the effectiveness of bleach for killing bacteria drops dramatically. If you can either see or remove with a fingernail the biofilm from a surface the chances of killing bacteria with soaking is not much over zero. For more than you want to know about biofilms click on this: Biofilm
2. The standard ppm for soaking (see bleach dilution table) is 2,000, not 500. This assumes that the equipment does not have a significant biofilm.
My best bet for solving her "persistent scours problem" in this sanitation situation? Just bite the bullet and wash all the equipment after every use. Click HERE for an effective washing protocol.