7 ways to preserve food
7 common ways to preserve food are:
- Curing and smoking
Preserving food by freezing
Freezing is the most widely used method of food preservation since it can be done easily at home by anyone and food is preserved for 3 to 12 months. Freezing is especially used for fruits, vegetables and meat products where the original taste and texture needs to be preserved.
Freezing food reduces the enzyme activity in food that causes spoilage. Freezing also crystallizes the water in the food so microorganisms cannot use it for growth.
Freezing itself does not significantly reduce the nutrient content of food. However blanching before freezing and defrosting will cause the loss of some nutrients, mainly water-soluble nutrients such as vitamin C.
Preserving food by dehydrating
Dehydrating is one of the oldest methods of food preservation. Dehydrating works by removing the water from food, thereby reducing the growth of microbes that cause spoilage. Dehydrated food has a long shelf-life and can be stored for up to 5 years under the proper conditions.
Food has been dehydrated by natural sun-drying for ages. Now there are electric dehydrators which can be used at homes. Food can also be dehydrated using an oven or a microwave.
Preserving food by pickling
Pickling is a method of preserving food by immersing in a solution of acidic brine or vinegar. Pickling adds a distinct flavour to food and pickles are used as side dishes and garnish in many cuisines.
Properly produced pickles can be stored for about a year. However, they must be refrigerated after being opened.
Some commonly pickled fruits and vegetables include mangoes, cucumber, limes and radishes.
Pickles have a high content of sodium due to all the salt added for pickling. So eating large portions of pickles is not recommended. Pickles are also not recommended for people with hypertension and cardiovascular diseases due to the high sodium content. However, pickles made with vinegar were found to be beneficial to people with diabetes.
Preserving food by fermentation
Fermentation is easily confused with pickling. The difference is that there is no addition of an acidic medium such as acidic brine or vinegar during fermentation. During fermentation, the carbohydrates in food are broken down into acids or alcohols by bacteria and yeast.
Fermentation preserves most of the nutrients and also produces probiotics. Probiotics are beneficial bacteria that help in maintaining gut health and improving immunity.
Some commonly fermented foods include cheese, yoghurt, sauerkraut, wine, beer and sourdough bread.
Preserving food by canning
Canning preserves food by killing the microorganisms that cause spoilage. Canning can be done at home using the correct equipment and proper sterilization of jars but it is time-consuming and needs practice.
Canned foods are shelf-stable for years and do not need refrigeration until they are opened. However, the heating process during canning reduces the nutrient content of food.
Canning is now done on a variety of commercial foods such as beans, corn, tomatoes, pineapple etc.
Preserving food by dry-salting
Dry-salting is simply the addition of salt to food. Dry-salting is related to pickling, but dry-salting can be done on foods without adding moisture by a brine or vinegar solution.
Salt is used as a preservative as it draws out water from the food thereby starving the microorganisms. Salt also kills some microbes by creating a pressure difference and rupturing their cell walls. Most bacteria cannot grow in an environment where the salt content is greater than 10%.
Dry-salting has the same disadvantages as pickling due to the high salt content used and must not be consumed in large portions. Dry-salting is mainly used in the fish and meat industry. Commonly dry-salted foods include beef jerky and salted dry fish.
Preserving food by curing and smoking
Smoking is a technique used to preserve food by dehydrating the food using smoke. Dehydrating and high temperatures will kill the microorganisms while smoke imparts a distinct flavour to the food.
Smoking food can be done at home and is also done on a large scale commercially. Fish and meat are among the most commonly smoked food products.
To preserve food for longer it is necessary to cure the food with salt before smoking. Cured and smoked meat can last for about a year. Cured and smoked meats have been linked to cancer in some studies so their consumption must be limited.
In this brief guide, we answered the question “7 ways to preserve food”. We discussed 7 methods of food preservation and looked at the benefits and implications of each method.
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