Food preservation

 

      

🥫 Food Preservation — Simple Science and Everyday Methods

Introduction

Food preservation is the practice of keeping food safe from spoilage so it stays edible, nutritious, and tasty for longer. In everyday life, we preserve food to avoid waste, save money, and ensure a steady food supply.

In this article, you will learn:
✔ What food preservation is
✔ Why it is important
✔ Common traditional and modern methods
✔ Science behind preservation
✔ Practical examples

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🧠 What Is Food Preservation?

Food preservation means using techniques to slow down or stop the processes that cause food to spoil. Spoilage happens when microbes (like bacteria and fungi), chemical changes, or insects break down food.

Preservation helps keep food:
✔ Safe to eat
✔ Nutritious
✔ Fresh longer
✔ Good quality

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📌 Why Do We Preserve Food?

Food preservation is important because:

🍎 Prevents spoilage — slows microbial growth
💰 Reduces food waste — less thrown away
🌽 Ensures food availability — out of season and emergencies
🛡️ Protects against illness — unsafe food can cause sickness
🚗 Helps storage and transport — long journeys and markets

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🌡️ How Food Spoils

Food goes bad due to:

✴ Microorganisms

Bacteria, yeasts, and molds break down food, producing bad smell and taste.

✴ Enzymes

Natural enzymes continue to react after harvest, causing ripening and decay.

✴ Chemical Reactions

Oxidation changes color and flavor (like cut apples turning brown).

✴ Insects

Worms, flies, and pests eat stored grains and fruits.

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🍎 Major Food Preservation Methods

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🧊 1. Refrigeration and Freezing

Cold temperatures slow down microbial growth and enzyme activity.

✔ Refrigerator (4–5 °C) — slows spoilage
✔ Freezer (-18 °C or lower) — stops microbe growth

Examples:

• Store milk, vegetables, meat, and leftovers

• Freeze fruits for future use

✔ Pros: Keeps food fresh longer
✖ Cons: Requires electricity

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🧂 2. Salting and Curing

Salt draws water out of food, reducing moisture that microbes need to grow.

Example foods:

• Salted fish

• Salted meat

• Pickles

✔ Pros: Simple and effective
✖ Cons: Food becomes salty

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🍯 3. Sugaring

Sugar works like salt — it reduces water available for microbes.

Examples:

• Jams and jellies

• Fruit preserves

✔ Pros: Sweet and safe
✖ Cons: Adds sugar

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🍋 4. Acidification (Pickling)

Adding acids (like vinegar or lemon juice) lowers pH, making food microbe-unfriendly.

Examples:

• Pickled mango

• Lemon pickles

• Sauerkraut

✔ Pros: Adds flavor
✖ Cons: Can be sour

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🔥 5. Drying / Dehydration

Removing water prevents microbe growth. Food becomes lightweight and easy to store.

Examples:

• Dried fish

• Dried fruits

• Sun-dried grains and grains

✔ Pros: Long shelf life
✖ Cons: Requires good drying conditions

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🔥 6. Smoking

Smoke dries food and adds chemicals that slow microbial growth.

Example:
Smoked fish and smoked meat

✔ Pros: Adds flavor
✖ Cons: Not suitable for all foods

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🔬 7. Canning

Food is sealed in jars or cans and heated to kill microbes.

Examples:

• Canned fruits

• Canned vegetables

• Canned fish

✔ Pros: Long shelf life
✖ Cons: Requires proper technique to avoid contamination

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📊 Diagram: Methods of Food Preservation

Here’s a simple visual you can insert in your blog:

Use this diagram to help readers visually connect how each method works.

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🧠 How Preservation Works (Science)

Most preservation methods work through:

✔ Removing or reducing water

Microbes need water to grow.
Dried, salted, sugared foods have less water available.

✔ Changing pH

Acidic environments (pickles) prevent microbial growth.

✔ Heat sterilization

Canning uses high heat to kill microbes.

✔ Cold storage

Cold slows all microbial and enzymatic reactions.

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🌟 Practical Everyday Tips

✔ Store leftovers in the fridge within 2 hours.
✔ Wash and dry food before storing.
✔ Use airtight containers.
✔ Label food with dates.
✔ Freeze what you can’t eat soon.

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📌 Summary

Food preservation protects food from spoilage by using methods like:

🍲 Refrigeration
🧂 Salting
🍯 Sugaring
🍋 Pickling
🔥 Drying
🔥 Smoking
🧪 Canning

These methods help keep food safe, tasty, and available longer while reducing waste and saving money.                                       

  

GREEN HOUSE GASES

Greenhouse gases, their effects, and reduction measures.

Do you know what a greenhouse is?

These are places where intensive agriculture is done. The greenhouse is a shelter covered by a transparent or semi-transparent substance. Mostly glass or transparent plastic. Selected plants are growing inside it with intensive care, which is free from pests and harsh weather conditions. It has a favorable environment, and the plants are supplied with the needed nutrients.

When plants grow in a greenhouse, the gas exchange will be balanced. That is, plants absorb oxygen gas in their respiration and release carbon dioxide. In photosynthesis, plants absorb carbon dioxide and release oxygen. The heat can be absorbed by the glass covering and warm the inside. So, a greenhouse is a perfect place for growing plants. This absorbed heat by the air in the greenhouse cannot be radiated back to the environment. So, even in winter, a considerable warmness is prevailing inside the greenhouse.

Likewise, solar heat radiation heats the land and water. Some of them radiated back to the space. When there are some types of gases (namely greenhouse gases) in the atmosphere that are mostly released due to human activities, they can absorb some of the heat energy that is radiating back. So, extra warmth will be generated in the atmosphere. So, the temperature rises up.

According to the comparison between a greenhouse and the earth, we can see the similarities between them. So, the term greenhouse effect is used in explaining the global warming concept.

There are two types of greenhouse gases: natural gases and industrial gases. For natural gases, there are carbon dioxide, methane, nitrous oxide, and water vapor. Methane is naturally produced in marshy lands. But marshy lands are very important in controlling floods and providing a good habitat for various animals, including birds. On the other hand, cattle farming also contributes much to the methane percentage in the atmosphere.

As for industrial gases, chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC), and sulfur hexafluoride (SF₆).

Both types of the above gases trap heat energy. That is, these gases prevent the radiating back of heat energy to the space. So, the result is global warming.

The contribution to global warming is different in the above gases. The gas that contributes most is carbon dioxide. Secondly, the methane.

Now we can consider the bad effects of global warming. Due to rising temperatures, glaciers and ice caps in the Polar Regions start to melt. It will cause an increase in the water levels of oceans. Further, the volume of water masses will increase due to the expansion of water, which results in increased temperature. This will cause the drowning of coastal cities and lowland lands. Further, seawater will mix with brackish water in estuaries and fresh water in rivers. In this way, those ecosystems may be unfavorable for the dwellers in them.

Climate change is also a result of global warming. So, unexpected frequent storms, hurricanes, wildfires, heatwaves, and droughts are some of the climatic changes. Some animals are directly affected by these changes. In the last 2 decades, we experienced a large number of wildfires. When a wildfire occurs, an uncountable number of living beings will get destroyed. The damage done to the flora and fauna of those places cannot be estimated.

Following are the regions of the world that experienced mostly this situation in the last 2 decades.

Australia, Russia, Canada, USA, Amazon Forest.

In 1972, all the state leaders in the world gathered and discussed the ecological crisis and destruction of the environment. They have declared the 5^th of June as World Environment Day. Accordingly, so many activities are done to protect the environment.

The measures should be taken to reduce the production of greenhouse gases, hence global warming.

As a country and as citizens, we can do more to reduce global warming.

We know that we are burning fossil fuels in many ways to get our power supplies. For example, diesel powerhouses and coal powerhouses are used to get electricity. The vehicles are using petrol and diesel. These are the main methods of emitting carbon dioxide into the atmosphere. By reducing the power consumption and going to a simple lifestyle like our grandparents, we can help with this issue.

In our day-to-day lives, we can contribute much to reducing the emission of carbon dioxide. Some of them are here. If we use public vehicles instead of private, it helps to reduce fuel consumption. At home, we can reduce power consumption by using natural resources like sunlight, bulbs, and fresh air by replacing fans and air conditioners. We can reuse and reduce the consumption of plastic shopping bags, which are used daily in large amounts.

We can limit the consumption of processed food, which uses more energy in processing. Planting fruit trees and vegetables in our own gardens (if we have them) helps us to add more fresh things to our diet and is a better way to reduce carbon dioxide.

At the country-level, heads of the states can take many measures to reduce the addition of carbon dioxide to the environment. In tropical countries, they can go for renewable resources to produce electricity like solar power (light energy), wind power (kinetic energy), and hydropower (kinetic energy of flowing water). The kinetic energy of tidal waves can also be used to generate electricity. Some countries that have good technology use geothermal energy as their energy resource to produce electricity. Some of the countries are the US, New Zealand, the Philippines, and Mexico. These methods reduce fuel consumption. Windmills are mostly found in Denmark and use the kinetic energy of blowing wind to generate electricity. The freely obtainable renewable energy resources are very important for countries because non-renewable fossil fuel is very expensive these days.

It is a very easy and useful way of reducing carbon dioxide levels in the atmosphere: reforestation. Trees absorb carbon dioxide from the atmosphere for photosynthesis, which is a natural process, and the whole biosphere depends on that. Therefore, reforestation could be the best solution to reduce the extra carbon dioxide percentage in the atmosphere. (The normal carbon dioxide percentage of the atmosphere is 0.04%.). Trees can absorb carbon dioxide for photosynthesis and release oxygen.

Some large cities are completely dependent on renewable resources for their energy consumption. For example, Stockholm, Sweden. The concept of green cities is a good solution for a clean atmosphere. Many countries are practicing this for a sustainable lifestyle. For example, Stockholm in Sweden, Berlin in Germany, and Amsterdam in Netherlands.

 

National Sanctuaries in Sri Lanka

https://youtu.be/4-wNY-p9cDc 

You can watch how a Varanus (monitor) searches for food by clicking the link above.

                                         Famous Natural Sanctuaries in Sri Lanka

In Sri Lanka, there are so many valuable ecosystems with high biodiversity. The Sri Lankan government needs to protect these valuable resources. So, about five decades ago the natural sanctuaries concept was established. Accordingly, a large number of lands are named sanctuaries and protected by the Sri Lankan government with the aid of the  Department of forest conservation. There are other organizations including the Central Environment Authority, The wildlife and nature protection society, and Rain forest protectors of Sri Lanka to help in this purpose.

Some people in the country go against these rules and regulations and do illegal things like cutting trees, hunting animals, and clearing the land to cultivate Cannabis sativa (ganja or marijuana)which is prohibited to cultivate in Sri Lanka. Some of the forest field officers have sacrificed their lives when they tried to prevent these illegal hunting (by poachers) and other unlawful acts.

The government allows people to visit these places and see natural beauty and if they need, can do research about the flora and fauna found there. But in most of these sanctuaries, there are government offices and managers for the management of the sanctuary and they charge some entrance fees from visitors.

There are about 70 sanctuaries found in Sri Lanka and here I am mentioning only about the sanctuaries which are highly attracted by both native people and tourists.

Some of them are given below.

 Yala sanctuary, (Ruhunu national sanctuary), Wilpaththu National sanctuary, Galoya National sanctuary, Horton plains, Minneriya National sanctuary, Udawalava National sanctuary, Wasgomuva National sanctuary, Maduru Oya National sanctuary.  Bundala National sanctuary, Kumana National sanctuary,

The paths you can use to reach these places are given below.

To Yala sanctuary: From Colombo to Matara, then to thissa maharamaya, Then to Kirinda, and to Palatupana where you get the main entrance.

To Wilpaththu sanctuary: From Colombo to Negambo – Chilaw- Puttland and via Thimbiriweva to the sanctuary.

To Galoya sanctuary: From Colombo to Kandy- Mahiyanganaya –Ampaara – Inginiyagala

To Minneriya National sanctuary: From Colombo to Kurunaagala- Habarana – On the pathway from Habarana to Polonnaruva. The office is at Ambagaswava.

Horton plains: Colombo – Nuvaraeliya- Ambewela –Pattipola.

Udawalava National sanctuary: Palmadulla-Ambilipitiya-Thimbolkatiya- Via Thanamalvila

Wasgamuva National sanctuary: Mahanuvara- Vilgamuva

Bundala National sanctuary: Colombo- Gall- Mathara-Hambanthota- Kirinda

Kumana National sanctuary: East of Yala sanctuary

MaduruoyaNationalsanctuary: 

 Colombo-Polonnaruwa-Manampitiya.

There are tourist bungalows also if you are willing to stay a night or two.

 Some of the economic and aesthetic value of Yala sanctuary.

  This is one of the oldest national sanctuaries in Sri Lanka. It is much famous in Sri Lanka and overseas. Because there are many beautiful Srilankan elephants. There are many other large mammals also. Dotted deer, leopards, wild buffaloes, wild pigs, and monkeys are some of them.

                                

 

a herd of wild boars

                           They like to live in herds. In one herd there are maybe 10 to 15 individuals. Wild boars are with short tusks. They can attack people using these. They like to rest in puddles which can be seen here and there. They are omnivores. They eat young leaves, grass, small rodents and dig the soil to find yams and roots.

                        

Dotted deer, Males with antlers.

These ungulates are vegetarians and easy prey of leopards. They are also live in herds. They can run fast to escape from carnivores. These dots simulates the light patches which come due to the sunlight

 Elephants are the keystone species of the forest. They make paths in the forest by clearing the shrubs, and other animals use those as their footpaths. Further, they use their tusks to dig and find water bodies in drought season and all the other animals depend on that water. So, they do a major role in an ecosystem to keep its balance. They can walk miles and miles without getting exhausted. They change their habitats from time to time. They travel from one forest ecosystem to another, which are miles away from each other.

 Some poachers kill the elephants with long tusks to get their tusks. Ivory carving is done by using tusks and making different ornaments that are more expensive. In Sri Lanka tusks are used as a symbol of power and sovereignty.

Drinking water in a  puddle

 A single elephant

      So many puddles and many large water bodies can be seen here and there in the rainy season, but in drought season elephants have to go searching for water and dig for water. Then other animals also use that water. In this way, they rescue the other animals.

 Peacock, the king of the birds. Now we're lucky to have this magnificent bird in our villages also. The male bird has very long tail feathers. These feathers are decorated with a colorful design. When the sun shines they make a dance by spreading their long feathers of the tail. But the female birds do not have such beautiful tail feathers. Some people consider this bird as a vehicle of the god, Skandha Kumara.

There are a considerable number of peacocks in the sanctuary. They cannot fly high. Live mostly on the ground and rarely fly onto the small shrubs. These are omnivores and feed on fruits, grains, flower petals, small insects, and mollusks.

A Peacock  with the folded tail feather

   

A  pelican

                      There are other birds like pelicans, kingfishers, and cranes who are like to live in swampy areas near water masses. They feed on fish, aquatic reptiles, and amphibians. 

In Kumana and Bundala sanctuaries there are large flocks of migratory birds. From April to June, thousands of migratory birds visit Kumana. Kumana is a swampy area and is a breeding ground for different bird species.

One of the vehicles used to travel in Yala sanctuary. Visitors have to hire a vehicle or two according to the number of visitors. Sometimes the path is narrow and muddy. But the drivers are skillful and take you a smooth aesthetic ride. Happy rides in Sri Lankan sanctuaries.

     A jeep, use to carry visitors.