Why are food preservatives not required to inhibit the growth of bacteria in yoghurt?

Food preservatives are not required to inhibit the growth of bacteria in yogurt because the fermentation process itself relies on specific beneficial bacteria, such as Lactobacillus and Streptococcus, which create an acidic environment. This acidity inhibits the growth of pathogenic bacteria while allowing the desired cultures to thrive. Additionally, the low pH and high competition from these beneficial bacteria naturally help preserve the yogurt, making additional preservatives unnecessary.