The deterioration of food mostly caused by natural decay or contaminated with micro-organisms. There are various factors which are responsible for food spoilage such as bacteria, mould, yeast, moisture, light, temperature, and chemical reaction.
*Bacteria. They are the most abundant microorganisms found on the earth. Psychrotrophic bacteria can produce large amounts of extracellular hydrolytic enzymes, and the extent of recontamination of pasteurized fluid milk products with these bacteria is a major determinant of their shelf life.
*Protozoa. They are single-celled microorganisms that cause disease like food poisoning etc.
*Fungi. They are found in damp and warm places and grow on the dead and rotting matter. Fungal spoilage of dairy foods is manifested by the presence of a wide variety of metabolic by-products, causing off-odors and flavors, in addition to visible changes in color or texture. Yeasts often colonize foods with a high sugar or salt content and contribute to spoilage of maple syrup, pickles, and sauerkraut.
*Environmental factors such as temp., moisture, air and light. High temperature and relative humidity favor the development of post-harvest decay organisms. Different types of bacteria require different temperatures. Some need heat: 40 - 700°C; others, low temperatures:0 – 400 °C; but most bacteria prefer the interval 30 – 400 °C.
*Time. The quality of food remains at its peak for sometime soon after its harvest/slaughter and thereafter as time progress, the deterioration in the quality of the food also progress. The harvested/slaughtered food must be cleaned and cooled immediately. This delays the onset of deterioration of food quality but does not prevent it.
The rate of spoilage of many dairy foods is slowed by the application of one or more of the following treatments: reducing the pH by fermenting the lactose to lactic acid; adding acids or other approved preservatives; introducing desirable microflora that restricts the growth of undesirable microorganisms; adding sugar or salt to reduce the water activity (aw); removing water; packaging to limit available oxygen; and freezing.
Food spoilage major causes
