Spoilage test

There are several methods to detect food spoilage.

pH indicators

Acidity increases as the food spoils; thus, acidity can be quantified to measure food quality. Food becomes more acid as the microbes' metabolism by-product increases. The pH level of food can be measured using pH electrodes/meters or titration.

Aerobic plate count

The purpose of aerobic plate count is to determine the number of microorganisms in a product. The suitable colony counting range is 25-250. The spiral plate method is the official plate count method used in the USA.