8.3.9 Unsafe temperature
An unsafe temperature for food storage is a major factor in food contamination. Many microorganisms need to multiply to a very large number before enough are present in food to cause disease in someone who eats it. However, if bacteria can have warm, moist conditions and an ample supply of nutrients, one bacterium can reproduce by dividing (on average) every half an hour and can produce 17 million bacteria in 12 hours! So, if you leave lightly contaminated food out overnight, it will be highly contaminated and infectious by the next day.
8.3.10 Poor personal hygiene