Some home-based food processing and preservation practices have been passed down through generations. Preservation refers to all actions humans take to stop or slow down spoilage by removing, killing or slowing down the micro-organisms that cause illnesses, or slowing down the natural chemical and enzymatic reactions that cause spoilage. Traditional preservation methods involve using high temperatures, low temperatures, dehydration (drying), high concentrations of salt or sugar, smoking, salting, fermenting and pickling.

Food processing differs from preservation in that it transforms foods from their raw state into a different form of food.

Traditional home-based food processing and preservation can help to maintain the nutritional value of food by preserving vitamins and minerals that are often lost during commercial manufacturing processes. These methods help to extend the shelf life of food and reduce food waste.

Home-based food processing and preservation also have economic benefits. Families can save money on groceries and reduce their dependence on store-bought products. This can be especially important in areas where fresh produce is expensive or difficult to obtain. Preserving food allows people to cope during food shortages that may have been caused by the seasonal unavailability of food and natural disasters like hurricanes and droughts. Having preserved food available at home therefore contributes to food security.

Here are some simple, traditional food preservation methods:

• Drying removes water from the food to slow down growth of germs and chemical-enzyme action.
• Salting makes water in food tissues unsuitable for germs/micro-organisms to grow in.
• Sweetening/candying, or preservation by sugar, removes water from food tissues, making it difficult for germs/micro-organisms to grow or survive.
• Chilling or refrigeration exposes food to temperatures between 0°C and 5°C and slows the growth of germs.
• Freezing — keeping food in temperatures below 0°C — completely stops the growth of germs.
• Heating – pasteurisation, blanching, and sterilisation.
• Smoking removes most of the moisture in food and is used to preserve meat, fish and seafood.
• Pickling increases the acidity or sourness of food and makes it difficult for germs to survive.
• Fermenting increases the acidity or sourness of food, which changes the taste and increases the nutrient quality.

Adapted from Naika, A. (2020). Preserve your own food. Promoting healthy eating through home food processing and preservation. Food and Agriculture Organization of the United Nations. https://www.fao.org/3/cb2113en/CB2113EN.pdf
Licence: CC BY-NC-SA 3.0 IGO

Activity

Go online and read the booklet Preserve Your Own Food: Promoting Healthy Eating through Home Food Processing and Preservation. It is a practical guide to simple methods and techniques for preserving food at home.

Naika, A. (2020). Preserve your own food. Promoting healthy eating through home food processing and preservation. Food and Agriculture Organization of the United Nations. https://www.fao.org/3/cb2113en/CB2113EN.pdf
Licence: CC BY-NC-SA 3.0 IGO

Activity

Now watch the video How to Store Raw Mango for Long Time by Pai’s Kitchen. It explains how to preserve mangos and provides recipes for making mango chutney as an appetisers or side dish.

Innovations in food processing and preservation

Here is a list of some innovations in food preservation and food processing that you can adapt for household use.

• Chemical preservatives such as sodium benzoate and benzoic acid are commonly used for preserving a wide range of foods as jellies, pickles, sauces and juices.
• Hot fill consists of applying a short blast of high heat (194–203°F or 90–95°C) to foods and their containers to kill all bacteria when the product is being packaged. This technique is used for drinks, juices and vinegar-based sauces.
• Cold fill consists of applying a short blast of extremely low temperatures to food packaging to sterilise the contents and avoids the use of preservatives, especially in dairy products.
• Reverse osmosis is a water purification technique to filter out contaminants and sediments like chlorine, salt and dirt from drinking water. It is used for many bottled water products.
• Liquid sterilisation is a technique in which the material is soaked in a sterile solution for a specified period of time and at a specified temperature.
• Retort processing involves sterilising, pasteurising or exposing a food and its packaging to high temperature to make both safe for human consumption. The retort pouch is a packaging material used instead of cans.
• Instant powder products are solid foods that are dried then pounded or pulverised to form light, tiny, loose particles that can be rehydrated.

Many of these innovative techniques require special equipment when they are used on a large scale, but there are techniques, tools and machines that you can use for household- or community-level food processing. There are machines for:

• steaming/blanching food
• peeling coconuts/disintegrating jelly/dicing and shredding/extracting coconut milk/shredding desiccated (dried) coconut
• solar and drum drying
• extracting cane sugar juice
• sterilising cans
• stripping the skin from seeds
• sealing plastic bags
• chopping, cutting, mixing and emulsifying a wide variety of food products
• heating, rolling and roasting peppercorns, nuts, beans and seeds
• peeling corn kernels
• dicing/shelling/milling/pulping/removing rinds for making pastes (such as curry)
• heat sterilising

Pakistan is one of the world’s largest producers of rice and wheat, and it processes cereals and pasta using high temperatures. Agri-processing is used for producing milk, flour, sugar, pulses and grains. It is also used in the fruit and vegetable subsector (particularly for making citrus and mangoes into jams, jellies, and marmalades etc.). Small- and medium-sized producers make edible oils which are processed into ghee and cooking oil.

In Malawi, small- and medium-sized food processors produce cereals from maize or corn. Farmers process sweet potato and soy and turn cassava into makaka, kanyakaska and kadonoska.

In Mozambique, the most important processed products are sugar, cashew nuts, soft drinks, tea, frozen shrimp, cornmeal, wheat flour and bread and cooking oil.

In Sri Lanka, thousands of smallholders plant tea to earn a living. Most Ceylon tea is produced according to artisanal and traditional methods compared to the mechanised cut, tear and curl method which is practised worldwide. (See “Tea production in Sri Lanka,” 2024, for more information.)

Reading

Tea production in Sri Lanka. (2024, 23 February). In Wikipedia. https://en.wikipedia.org/wiki/Tea_production_in_Sri_Lanka
Licence: CC BY 4.0 (https://en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License)