We have a fairly simple operation where we blend 4-6 powder raw materials to create a protein powder.
The only machine we use is a ribbon blender.
We combine the raw materials in a specific order and run the machine for preset times after each material is added. At completion, we acquire a representative sample & send off for lab analysis for aerobic plate count, ecoli, yeast & mold. All are consistently <10 with the exception of APC. Which vary greatly sometimes over 100.
My cleaning & sanitzation consists of scrubbing blender with detergent after use. Then sanitizing with steam then quat prior to use. We ATP swap test the blender before use & see very low results, often below ten or around ten RLU. All utensils & table surfaces are sterilized with quat. floor is mopped prior. The outer layer of the bags of whey powder are peeled away before touching the blender.
I have received large variations in test that were on batches that we run back to back. I would think these would have almost the same results. I realize that my raw material plate count will effect my final prouct plate count.
I can't think of anything that would be causing contamination. However I do not have a vast understanding of the aerobic plate count.
Im asking for some direction in where/how to learn more about this so I might be able to adjust any methods that are not working.
I was thinking that my A/C system may be causing an issue.