In mice, the ld50 for staphylococcal enterotoxin is 1350 ng/kg, and the ld50 for shiga toxin is 250 ng/kg. which of the following statements is true? a) more organisms of staphylococcal bacteria must be ingested to cause infection, as compared to shigella bacteria. b) staphylococcal enterotoxin is the more lethal of the two toxins. c) shiga toxin is more lethal than staphylococcal enterotoxin. d) the parenteral route is the preferred portal entry for shigella bacteria.