The various actions of micro-organisms result in the loss of edibility or nutritive value of food. By canning, pickling or drying, the life span of some foods can be increased. Studies have revealed that many of the chemical food additives contain harmful substances. Therefore, it is better to opt for food preservatives that occur naturally, which are free of toxins. Read on to know more about the commonly used natural preservatives.
The nutrients that give us energy and help us maintain good health also cause our food to spoil. There are innumerable micro-organisms in the atmosphere that derive their nutrition from these nutrients by breaking them into simpler forms. As these minute life forms start disintegrating the nutrients, they set off the process of food spoilage. With the knowledge of the role that micro-organisms play in spoiling food, a number of methods of food preservation have been developed by man. All these methods work by altering conditions like temperature, availability of water or oxygen in the food, or in the environment in which the food is stored. Changing or altering these factors hinders the growth of these minute organisms, and hence prevents food spoilage.
How Food Are Wasted?
Ways to Reduce Food Waste
1. Think before you shop – more than a third of us go shopping without a list.
- Check what you have at home before you shop.
- Make a list – it saves time and money.
- Shop with meals in mind – you’ll end up throwing less away.
2. Use or lose your food – 60% of us end up throwing away food because it’s passed its ‘use-by’ date.
- Plan your meals with the ‘use-by’ date in mind – it will save you money.
- Know your fridge – keep an eye on what’s inside. Be mindful of the perishable food you have and plan meals to fit in with their ‘use-by’ dates. This will prevent unnecessary waste.
3. Befriend your fridge – 70% of our fridges are set at too high a temperature.
- Store food according to the instructions on pack – leaving food out of the fridge can cut the life of foods like milk, cooked meats and salad by up to 100%.
- Keep your fridge between 1-5°C – this helps you get the best from your food. If your fridge doesn’t indicate actual temperature, think about investing in a fridge thermometer.
4. Love your leftovers – more than half of households say they throw away food because they’ve cooked too much.
- Using leftovers to make delicious meals is a smart way to ensure you eat everything you buy.
- Recipe for leftover turkey: Turkey biryani with red onion and coriander.
- Recipe for left over sausages: Orecchiette pasta with a quick and easy creamy sauce.
- Recipe for left over cheese: Potted stilton with port
5. Feed your garden – on average over 70% of household waste is landfilled each year. Composting reduces the amount of rubbish you put out for collection and creates a free, nutritious fertiliser that will help make your garden more beautiful.
- Compost your kitchen and garden waste. Everything from uncooked vegetable scraps to fruit peelings, teabags, coffee grounds, eggshells and small amounts of paper and soft cardboard can be home composted.
Methods for Preserving Food
Food preserving is a method of storing both raw and cooked food for an extended time by using food preservatives. Food packaging on the other hand, protects food and provides information regarding the packaged food. Food preservatives are substances added to food products to prevent decomposition due to adverse chemical change or microbial action. The main objective behind using food preservatives is to preserve the appearance, texture, flavor, edibility and nutritive value of the foods and also to prevent from food poisoning.
Food preservatives can be either natural or man-made substances. Based on their action, they are broadly classified into three. They are antimicrobial preservatives, antioxidant preservatives and another third type preservatives, which target enzymes in the food itself. Antimicrobial preservatives inhibit the growth of microbes such as bacteria and fungi, whereas antioxidant preservatives inhibit the oxidation of fats, lipids and other food ingredients. The third type of preservatives blocks the natural ripening and aging of the foodstuffs after harvest. In addition to using preservatives, there are other healthy ways of preserving food, for example, processes such as drying, salting, smoking, pickling and freezing can also preserve foods.
Drying: This is one of the oldest methods of food preservation. This process acts by reducing the moisture content in the food which in turn arrests bacterial growth. Drying is largely used for preserving meat. However, fruits and vegetables can also be preserved by this method. The additional advantage of drying is that it reduces the size and weight of the food product, therefore making it more portable. Sun drying, oven drying, and drying with the help of a dehydrator are the various ways used to reduce the water content of food.
Freezing: Micro-organisms require a certain level of temperature for their survival. Freezing foods lowers the temperature to levels that make the environment unsuitable for microbial growth. This is the principle on which home refrigerators work. Cold stores are used to preserve large amounts of food stuff for a longer period of time, so that they can be used during a natural calamity or national emergency. The only drawback of this food preserving technique is its dependence on electricity.
Canning: In this process, the food is first processed and then sealed in airtight containers. While the micro-organisms are killed by processing the food, their entry and proliferation is restricted by canning it in an airtight environment. The various methods used to process the food before it is canned are pasteurization, boiling, freezing or vacuum treatment.
Vacuum Treatment: In this method food is stored in airtight containers that strips bacteria of the oxygen that helps it carry on with its metabolism. Hence, the growth of these micro-organisms is arrested and food is preserved. Nuts are usually preserved by this method.
Sugaring: Sugaring is used to preserve fruits like apples, apricots and plums in sugary syrup that dehydrates the foods. The skin of certain fruits are cooked in sugar till they crystallize and then they are stored in a dry environment.
Salting: Salt is a natural food preservative that draws out moisture from the food as well as from the cells of the micro-organisms that may be present in it. Lack of moisture kills these organisms and hence prevents food spoilage. Salt is commonly used as a preservative in meat products.
Pickling: Cucumber, beef, peppers and some vegetables may be preserved by pickling. This technique involves dipping the food in some liquid chemical that prevents the growth of micro-organisms but still maintains edibility of the food. The preserving liquids used are vinegar, brine, alcohol and some other oils. This process is known as chemical pickling. The other way of pickling is by fermentation. In fermentation pickling, the preservation agent is produced by the food itself during the process of fermentation.