According to chapter 9 in fast food nation, how does manure get into the meat at slaughterhouses and hamburger grinders?
a. cooks fail to bring meat to a high enough temperature to kill pathogens.
b. manure is deliberately shoveled into piles of meat to increase the volume.
c. workers sometimes put meat that was dropped on the floor back into the production line.
d. visitors often fail to clean their shoes, and they spread infectious agents on the floor.