What is it about using bleach that we think it is magic? Just toss some calf feeding equipment into a sink that is full of a strong bleach solution - "Presto" - all the bacteria are gone? No, it is not going to happen. 

These two sinks are full of nursing bottles, nipples, and tube feeder equipment. I was assured that this day-long soaking in a strong bleach solution every two weeks or so kept the equipment clean. 
Why am I doubtful about this method actually working well to reduce bacteria levels on equipment? In one word, "biofilm." One estimate compared the effectiveness of bleach in killing bacteria on a clean surface and a surface with a biofilm - the kill rate on biofilm protected surfaces was 1,000 times lower. 
From a positive perspective, if the equipment is already completely clean this chlorine solution will give an excellent kill rate for bacteria on the surfaces. Notice I said, "completely clean" meaning there is not a residual film of proteins and fats.
However, it is easy for a biofilm to develop on equipment if it is not cleaned completely after EVERY use. For example, washing feeding buckets every morning and then just rinsing them after the afternoon feeding will allow the biofilm to accumulate. If you are curious about biofilms you may want to read this resource - click HERE.
These biofilms are thin enough that we can't see or feel them. However, you can depend on them being present whenever there is a lapse in a regular and thorough cleaning protocol. For a review of a four-step cleaning protocol click HERE. This dairy did not use this four-step washing procedure -  they "rinsed" their equipment with hot water only and "soaked it clean" as shown above. 
On a follow up with the farm shown in the picture we were able to culture high levels of bacteria from both the nursing bottles and tube feeders AFTER they were "soaked clean."