You opened the fridge for a quick bite and what’s that smell? You saw your favorite meal left over from the beginning of the week in a plastic container, but when you opened the container, a smell that whetted your appetite attacked your nose. Rotting or spoiling of food is a natural part of the life cycle of all foods. So why and how does this happen?
All food exposed to the elements will rot. Once a food in the form of vegetables, fruit or meat is harvested, it is torn from its life-giving source. In other words, the cells of an apple begin to die over time, if not from the moment you collect them.
Some foods, such as fruits and vegetables, have thick cell walls that keep them edible for days or even weeks. However, these cell walls begin to break down over time (because every living thing dies). When the degradation begins, the enzymes naturally found in the cells that allow the food to mature leak out. These proteins begin to destroy neighboring cells, including healthy ones, and this process results in the degradation of fat, vitamins, flavor and color in the food.
Since food does not have an immune system, bacteria and fungi begin to eat the food and multiply. While eating, they leave waste products that alter the texture and taste of food. In the process, you will feel that the fruit and vegetables become less solid. It also starts to change color, smell bad and taste bad. There are also purely chemical decay mechanisms that cause food to spoil. Just like fat oxidation, which makes food taste sour.
So what is driving this change in food? Primary culprits include air, humidity, light, temperature and microbial growth. When two or more of these culprits come together, it speeds up the degradation process.
Causes of food spoilage
1.Oxygen and water effect on food spoilage
When food is exposed to air, microorganisms can land on that food and begin to break it down for consumption. The presence of oxygen promotes the growth of microorganisms such as mold and yeast.
Oxidation occurs in food that comes into contact with air. Because the oxygen attacks the fat in the food. When oil oxidizes, it smells heavily. That’s because the process creates short-chain small carbon compounds. Using ascorbic acid or citric acid protects against oxidation.
Every food consists of a certain amount of water. Microorganisms need to degrade food for energy and growth. They use the water in the food for this chemical reaction process. If there is moisture around food, it can allow mold and other microorganisms to grow outside of the food.
2.Light and temperature effect on food spoilage
When a food is exposed to light, its outer layer begins to degrade through a process called photodegradation. Photodegradation can cause both discoloration and loss of flavor, vitamins and protein. Light damages chlorophyll, which gives food its color.
Temperature also plays a role in food decay. As the temperature increases, the chemical reaction that causes deterioration accelerates. A mere 10 degree increase in temperature can double the decay. Putting food in the refrigerator or freezer therefore slows down the decay process.
Food spoilage isn’t all that bad, though. It is a natural process that releases nutrients in food and seeds, allowing them to be reused by living organisms in the environment. This process is part of the cycle that allows your favorite foods to come back. Nobody wants to drink spoiled milk, but souring the milk is an important step in cheese making!
How to protect food from spoilage
Since most people today do not grow their own food, food has to last a long time after it is bought and eaten. Scientists have developed many methods over the years to combat the main causes of spoilage such as weather, chemical reaction and microorganism.
The reason why food comes in packaging is not just for appearance, but to protect the food from air and light. Again, keeping food cold or freezing is to slow down the chemical reaction. Finally, a preservative chemical is added to the food to fight the microorganism. These chemicals serve to inhibit the chemical reaction in which the microorganism breaks down the food for energy.