Food gradually undergo deterioration or spoilage from the time they are harvested, slaughtered or manufactured. Some foods spoiled rapidly; others keep for longer but limited periods. The usual storage life of some fruits, leafy vegetables, and animal foods is less than 1-2 days at 21°C.The underlying principle of all preservation techniques, whether carried out at home or commercially is to restrict food spoilage sot that food can be used safely in a palatable form at a later time .Preservation methods are designed to inhibit the growth of organisms, the removal of organisms and killing the organisms. Food preservation should also arrest the biochemical breakdown of tissues and the transformation of cell contents. This is achieved by heat, cold drying, fermentation, radiation, and chemicals. Food deterioration also is bought about by any one of these techniques.
To minimize pathogenic bacteria – food in long-term storage is at serious risk of spoilage due to bacteria
To keep food at its best quality – food deteriorates over time due to spoilage. In many cases, mild spoilage doesn’t make food unsafe to eat, but it significantly affects its taste, texture, and appearance. Proper food preservation can help retain some of these qualities, as well as the nutritional value of certain foods.
To save money – waste is costly, both at home and in a commercial setting. Ideally, you should avoid buying more than you can use.
Food preservation methods range from the simple process of chilling to more complex procedures such as canning. Many are creative options that help you mix things up at home or sell food in various forms of packaging. Others help you keep your inventory in a commercial kitchen for much longer, which means you reduce waste and increase profit.
Here, we can find out some methods of preservation
Chilling is an important activity in food processing. Foods are chilled to extend shelf life by reducing biochemical reactions and microbial activity. Temperature control is essential in order to prevent spoilage and food safety concerns during storage. Foods are chilled using mechanical and cryogenic refrigeration systems. Cryogenic refrigeration is spraying or immersing the food directly with liquid nitrogen or carbon dioxide (liquid or solid). This intimate contact with the food improves efficiency of cooling by reducing cooling time and increasing output. Liquid nitrogen is often used for freezing rather than for chilling.
Freezing is one of the oldest and most widely used methods of food preservation, which allows preservation of taste, texture, and nutritional value in foods better than any other method. The freezing process is a combination of the beneficial effects of low temperatures at which microorganisms cannot grow, chemical reactions are reduced, and cellular metabolic reactions are delayed.
Sugar is used in the canning and freezing of fruits to improve flavor and texture, and to preserve natural color and shape. Through osmosis, sugar replaces some of the water in the fruit. This natural process preserves the fruit's inherent color, texture and shape by preventing the fruit's remaining water from leaving its cellular structures. As a result, the fruit's texture is protected against weakening during freezing and canning. In addition, sugar, upon entering the cells, helps minimize oxidation, and prevents the fruit's firm texture from becoming mushy. Sugar also increases the shelf life of products. For example, a fruit canned in a light syrup might not last as long as one canned with a heavy syrup. The same goes for those canned using alternative sweeteners.
Salt draws water out of food and dehydrates it. All living things require water and cannot grow in the absence of it, including the bacteria which can cause food poisoning. In very high salt solutions, many microbes will rupture due to the difference in pressure between the outside and inside of the organism. High salt can also be toxic to internal processes of microbes, affecting DNA and enzymes.
Canning is the process of applying heat to food that’s sealed in a jar in order to destroy any microorganisms that can cause food spoilage. Proper canning techniques stop this spoilage by heating the food for a specific period of time and killing these unwanted microorganisms. During the canning process, air is driven from the jar and a vacuum is formed as the jar cools and seals.
When foods are heated in containers or by other methods to a temperature below the boiling point of water for a definite period, the process is known as pasteurization. This process serves two objectives: it destroys pathogenic organisms associated with the food and extends the product shelf life by decreasing the microbial population, and inactivating some enzymes. The choice of temperature and the time of pasteurization will be influenced by the consideration of the purpose of the process, and the chemical and physical composition of food.
Unleash Your Potential: Elevate Your Abilities with Our Assessments.
