Which did society most likely observe when government agencies began requiring pasteurization in food?

Society has probably noticed that the quality of food has increased while the stomach problems caused by them have decreased.

Explanation:

Before pasteurization the population of the cities suffered serious problems with the quality of the food and even with their intake. This is because pasteurization completely eliminates pathogenic microorganisms from food, which in addition to causing stomach problems, make foods unsuitable for consumption.

Once pasteurization was created and its results were proven, the government decided to force food manufacturers to be able to market their products only when they were pasteurized.

with this, society must have noticed that the quality of the food has increased, since they managed to spend more time without spoiling, in addition, the stomach problems caused by improper food had their occurrences decreased.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).