This is most likely because the heat used in cooking such foods is insufficient to produce germicidal results.
"Food Poisoning"
Edwin Oakes Jordan
It was not necessary to close the chimney, for the germicidal gas is heavier than air, and fills a room exactly as water fills a tank.
"Northern Diamonds"
Frank Lillie Pollock
The effect of these substances upon the velocity of the germicidal action of bleach solutions is in the same direction as the hydrolysing effect.
"Chlorination of Water"
Joseph Race