How can I successfully isolate HUVEC from umbilical cords without using antibiotics?

At PromoCell; we get the umbilical cords from our tissue suppliers with no addition of buffers or media. This method prevents the microorganisms from being washed into the blood vessels. Before we start the cell preparation; the umbilical cord is also cut on both ends with a sterile scalpel to provide sterile intersections in addition to the sterile lumen. This method allows us to isolate sterile endothelial cells from umbilical vein and to plate them in antibiotics-free culture media.