Post Harvest Spoilage prevention of fruits and vegetables
Ashutosh Dubey and A.K. Verma
College of Basic Sciences and Humanities
G.B.Pant Univ. of Agri. & Tech. ,Pantnagar
Food spoilage may be defined as any change that renders food unfit for human consumption. Every change in food that causes it to lose its desired quality and eventually become inedible is called food spoilage or rotting. These changes may be caused by various factors, including, physical and chemical changes, such as the tearing of plant or animal tissues or the oxidation of certain constituents of food, may promote food spoilage. Foods obtained from plant or animal sources begin to spoil soon after harvest or slaughter. The enzymes contained in the cells of plant and animal tissues may be released as a result of any mechanical damage inflicted during post harvest handling. These enzymes begin to break down the cellular material. The chemical reactions catalyzed by the enzymes result in the degradation of food quality, such as the development of off-flavors, the deterioration of texture, and the loss of nutrients. The typical microorganisms that cause food spoilage are bacteria (e.g., Lactobacillus), yeasts (e.g., Saccharomyces), and molds (e.g., Rhizopus).
Causes of food spoilage
As soon as the fruits and vegetables are cut off from their natural nutrient supply, their quality begins to diminish. This is due to a natural process that starts as soon as the biological cycle is broken by harvesting. Once it is harvested, the agricultural product is edible for only a limited time, which can vary from a few days to weeks. The product then begins to spoil. We distinguish between various types of spoilage:
- Physical spoilage
- Physiological aging
- Spoilage due to insects or rodents
- Mechanical damage
- Chemical and enzyme spoilage
- Microbial spoilage
Physical spoilage is caused for example by dehydration. Physiological aging occurs as soon as the biological cycle is broken through harvesting. Neither process can be prevented, but they can be delayed by storing the agricultural products in a dry and draft-free area at as low a temperature as possible.
Insects and rodents can cause a lot of damage. Not only by eating the products, but also by passing on micro-organisms through their hairs and droppings. The affected parts of the plants are then especially susceptible to diseases.
Chemical and enzyme spoilage occurs especially when vegetables and fruit are damaged by falling or breaking. Such damage can release enzymes that trigger chemical reactions. Tomatoes become soft, for example, and apples and other types of fruit turn brown. The fruit can also become rancid. The same processes can also be triggered by insects: the fruit becomes damaged, which causes enzymes to be released. As soon as the peel of fruit is damaged by falling, crushing, cutting, peeling or cooking, the chance of spoilage increases considerably.
Prevention of Spoilage
To prevent harvested products from spoiling, they can be preserved: physiological aging and enzyme changes are then stopped or delayed and microorganisms are prevented from multiplying on the product. Enzymes can be deactivated by heating the fruit or vegetables. The same effect can be achieved by making the fruit or vegetables sour or by drying them. The peel of a fruit or vegetable provides natural protection against micro-organisms. To retain the desired quality of a product longer than if it were simply stored after harvesting, it must be preserved. To preserve food it must first be treated, with the goal of stopping physiological aging and enzyme changes and preventing the growth of micro-organisms
Recommended practices for preservation of fruits and vegetables
- Wash your hands thoroughly with hot water and soap before beginning to prepare food.
- Make sure that kitchen utensils and appliances are well cleaned and disinfected.
- Always store food in a clean place.
- Use herbs and spices as little as possible, because they are an important source of contamination.
- Use clean and pure salt only if the salt is not pure; heat it on a dry, metal sheet above the fire.
- Allow only clean drinking water to come in contact with fruits and vegetables.
- Never allow anyone who is sick or has open wounds to come in contact with food that is to be preserved.
Submitted by drashutoshdubey on Mon, 22/06/2009 - 17:32