Intrinsic and Extrinsic factors determines whether microbial growth will makes food stays longer or spoil quickly. Intrinsic factors such as PH, moisture content which is water availability, oxidation reduction potential, looks of the food, available nutrients, and microbial agent presence.
Also, Extrinsic factors such as temperature, relative humidity, gases present, and the amount of microorganisms present in the food.
Intrinsic Factors: low PH in foods helps in growing yeast and mold. If foods have neutral or alkaline PH such as meats, bacteria are more predominant in the Spoilage process, which can leads to the breakdown of protein in proteolytic and anaerobic which brings out bad smell of amine compound. Acid products like fruit, soft drinks and vinegar mostly don’t undergo bacteria Spoilage because of their high PH. Fruits normally undergo Spoilage by enzymatic and mechanical damage and sometimes by yeast and mold.
The availability of water helps the growth of microorganisms in foods. Spoilage can be controlled by simply drying the food to eliminate the Spoilage process. Water presence can be measured by activity of the water. Adding large quantities of salt or sugar can dehydrate and kill the microorganisms present in a foods because most organism can not grow in hypersonic condition.
Oxidation Reduction potential
Food Spoilage can be influenced by oxidation reduction potential.
If meat product like broth are well cooked it reduces the oxidation reduction potential. Hence electron loses its substrate it’s because of the oxidation reduction substrate. The loss or gain of the substrate means that oxidation reduction potential are at ease, when the elements loss or gain electron the substrate is said to be oxidized and it reduces when the substrate gains electron.
For microorganisms to grow well and function very well, water, sources of energy, source of nitrogen, vitamins, and growth that are related and minerals are needed by the microorganisms. Water is very important for most microbes although mold required lowest amount of water. In order to gain energy, food borne microorganisms may needs sugar, alcohol and amino acid. And some uses complete carbohydrates like starch, cellulose as source of energy. Most microorganisms required vitamin B in very low quantity and some natural foods do have an excess quantity for the organisms that are unable to synthesize their important requirements.