Food preservation is the method of reducing food waste by making it last longer. This is done by preventing the growth of bacteria, slowing oxidation of fats or inhibit visual deterioration.
Food Preservation Methods – how to preserve food
Food preservation involves more than one method ranging from boiling to sugaring and sealing to salting, curing, smoking and more
Food Preservation Methods
There is a good number of food preservation methods: natural and modern ones. Some are quite good while others are harmful to human health
Curing is the process of drying and adding flavours to food especially meat and fish. It is done by adding salt, sugar or nitrate/nitrite and often followed by smoking. This process is sometimes called salting or sugar curing.
Salt helps to kill the bacteria by drawing water out of them through osmosis. As bad microorganisms are reduced, good ones occur that are fed by adding sugar (dextrose). By consuming sugar, good bacteria create an acidic environment that prohibits the growth of the bad virus. And when the smoking process add flavors and chemicals to the food while preventing further growth of bacteria. Nowadays people also use food dehydrators to dry food in short period of people when compared to smoking or sundry
Nitrate and Nitrite on the other hand not only helps kills more bacterial but also adds flavour and pink/red colour while preventing oxidation. It comes in the form of either potassium or sodium nitrate. In itself nitrate is not harmful but research shows that when food treated by nitrates such as bacons are exposed to high temperatures, it forms nitrosamines particles that are harmful to the consumers.
2. Cooling / Freezing
Cooling is the process of freezing food such as vegetables, fruits, and meat/ fish using refrigerators or iceboxes. This helps slow down bacteria growth, reproduction and food rot causing enzymes.
It is the best way of preserving food for long period of time. To store raw potatoes for long time however, place them in a cool dark place.
To make better use of freezer at home make sure to buy a vacuum sealer. This will help prevent your food from getting in contact with dry air and coldness that leads to freezer burn. And for the cooked food make sure to cool it first before putting them in a freezer.
Boiling is the method of food preservation in which the food such as milk is boiled at high temperature. This helps kill available microorganisms. Remember to store food leftovers in the fridge to prevent growth of new microbes or rotting.
4. Sugaring vs Pickling
Sugaring is a good way of preserving fruits same as pickling. It is achieved by heating the fruits with sugar to help kill microbes. Sugar kills the bacteria by dehydrating them through a process called plasmolysis. Sugaring is what we use for making jelly and jams or storing fruits such as pears, plums, and apples in an antimicrobial syrup.
Pickling on the other hand is the process of placing fruits in vinegar, brine, vegetable oil or alcohol.
Lye is the process of reducing food acidity and lowering ph by adding sodium hydroxide to make it more alkaline which is unsuitable environment for bacteria to grow.
Canning is the process of boiling food such as meat, beans, peas and others then store in a sterilized can. The cans are then sealed and boiled in hot water using a pressure cooker to remove remaining bacteria. The boiling time differ from one type of food to another. And after boiling some food such as vegetables and meat with no natural acids needs addition of acidic elements.
Jelling is a method of cooking food such as fruits, seafood, and meat in materials such as gelatine, maize flour, and agar which then solidifies to form a gel.
Jugging is a method of preserving meat by stewing it into a tightly covered casserole or earthware. Gravy, brine, red wine or animal own blood is added in this food preservation method.
Underground Storage vs Confit
Underground storage is a method of preserving food such as root vegetables, butter and rice by storing them under sand, mud, ashes, hot coals, dry-salt land, ice . Many root vegetables such as carrots, cassava, and yams can last longer when stored in a dark, cool or salt environment such as in storage clamp .
Confit on the other hand is the method of preserving meat by first cooking it in lard or tallow at 100 degree centigrade, after finishing cooking immerse it in the fat then store it under cold ground or cellar.
Fermentation is the process of using microorganisms to convert carbohydrates and sugar to alcohol, carbon dioxide and organic acids under anaerobic conditions. It is used for producing drinks such as cider, wine and beer. This process is also used in bread and yoghurt , cheese, olives and vinegar making and preservation.
It is advised to sterilize all the containers and equipment used for fermentation. This is to help prevent the growth of harmful bacteria.
Pasteurization is the modern way of preserving milk by heating it at high temperature around 70 degree centrigrade for 15 to 25 seconds to remove bacteria and then cool it very faster to around 3 degree centrigrade. The milk is then stored in sterilized bottles a. The method used is called ‘high temperature short time.
Vacuum packing vs sous vide cooking
Vacuum packaging is the way of preserving food such as vegetables, cured meat, smoked fish, cereals, nuts, cheese and crisps by removing oxygen in its plastic film package before sealing it. It can done automatically or manually using a vacuum sealer. This process not only helps remove air, making it hard for bacteria to grow but reduce the volume of the content.
Vacuum sealing is very important in storing frozen foods, it help reduce freezer burn. The freezer burn occurs when the food in freezer get in contact with dry air and cold environment, it dries up to form leather like appearance. The burns also alters the texture and food flavour.
Sous Vide cooking on the other hand is the way of cooking vacuum sealed foods. Check our detailed review of the best sous vide cooker machines.
Irradiation is the method of using beta particles and gamma rays ionizing radiation to kill microbes in spices, sauces, mustard, and ketchup,. It is also used to delay fruit ripening and spoilage.
Modified atmosphere is the process of changing the grains and salad crops atmosphere making it unsuitable for microbes to grow in. This includes reducing oxygen and rather add carbon dioxide. However, it is claimed that while adding carbon dioxide to grains makes them last longer up to 5 years, adding to vegetables make them loose vitamins.
Pascalization is the use of high pressure to preserve foods such as orange juice . High pressure helps kill microbes, and slowing food spoilage while maintaining flavour, texture, freshness, and nutrients.
Biopreservation is the use of natural or controlled production of lactic acid bacteria (LAB) to help increase food shell life, and reduce spoilage while inhibiting bacteria growth. When these controlled bacteria compete for the food they produce acids such as hydrogen peroxide, acetic and lactic acids that aid in food preservation.
Hurdle technology is the method of using multiple food preservation techniques o prevent microbes growth. These techniques include increasing acidity, lowering storage temperature, processing food at high temperatures, removing air, dehydrating and more.
What is the Importance of Food Preservation
Food preservation was and still quite important from stone ages to date. This is because if done properly it helps:
- Kill Microbes – Bad bacteria cause illness so food preservation methods help getting rid of these viruses
- Reduce spoilage – Raw vegetables, fruits, fish, and meat get spoiled fast if left to stay at room temperature. preserving them helps increase their shelf life
- Save money – Preservation helps save food from being spoiled and ended up thrown away. This saves you money from buying new food rather use leftovers or fresh preserved ones.
- Increase food availability- There is some foods that are seasonal, preserving them helps to have them throughout the years. They can also be transported and made available in countries or places with food scarcity.
- Saving seeds. Not only crops that are preserved but also seed for future use. Store the ones from the most resilient plants, store them in a place that is dark, cool, and dry in an airtight container. Before storing the seeds needs to dry out first then add desiccant or an oxygen absorber in the container to extend their life. Do not forget to add labels and storage dates so you can plant older seeds first. In the future before planting them in a farm, do a germination test first to see if they are still viable.
Dried beans, white rice, wheat, sugar, honey, oats and pastas need a dry, dark cool room to make them last long. This is is the best way to preserve them but you need to use things like foil pouches, pete bottles and cans to protect them from rats and other rodents and harmful insects.
Wants your carrots, potatoes, pumpkins, turnips, beets, onions, and cabbages, and other root vegetables to last long? What about your nuts, pears and apples and other fresh produce? Construct your own root cellar when building a house or outside the house or build one in your basement or buy a coolbot. A cellar is a large underground room with a clear entrance, it is a low-cost way of storing food. it offers a cool, moist condtion, a needed environment for your produce to last long. You need to cross-check your storage regularly and remove any spoiled food. Pay attention to how long each product is lasting so you can know what works better and how to improve.
- To make an underground root cellar make sure to dig a hole that is deep enough to have a cool, moist environment. Its door need to face north to avoid much heat and light getting in. Also it needs to be covered with 1 to 2 feet soil
- Make sure to provide air circulation as some produce produces gas that if left in might spoil other produce.
- Construct the cellar floor using gravels or packed earth rather than concrete to help maintain a cool temperature
- The place needs to be dark as putting light will cause the veggies to sprout. Make sure the cellar windows are covered well to prevent light from entering the cellar.
- For making storage shelves use the rot-resistant natural woods that have not been treated. These are good at transfrering heat and keeping the place cool when compared to the metal shelves.
- A high humidity between 80 and 95 percent helps keeps your food from drying out. Higher humidity than 95 percent will cause canning lids to rust therefore be sure to check for signs of rust
- Some crops store better than others, test out to see which ones work out better for you.
- Need not to wash your produce before storing them, just wipe off the soil. Pack your produce in little damp fresh leaves, sawdust, sand or straws before storing them in a cellar
- Layer out your produce, those that need very low storage temperature store them below
- For crops that smell or produce gases such as apples, blueberries, ripening bananas, grapes, green oninons, plums, plantains, potatoes, pears and morestore them far from others as they might cause others to rot or absorb smell
- Make sure to track your root cellar temperature and humidity
- Keep your cellar out of external heat and lights by avoiding accessing it frequently.
- For ventilation, put 2 vents, the top one for letting fresh air in and the bottom one for letting the gases produced out. Vents need to be angled to keep rain and debrit from entering the cellar, also its outside area need a mesh to prevent rodents from getting in
Note the root veggies that are to be stored in the cellar need to be the ones that is matured enough. And you need to cure them for 10 days in a dry, dark, cool place for their skin to dry before putting them in a cellar. This also helps to prevent crops from rotting.
Examples of Foods that Last For Years
The following are examples of food if kept well can stay up to 20 years or more without spoiling, they make a good source for survival food:
- White rice but not brown rice – White rice has low-fat content when compared to brown rice. It is this low-fat content that makes it last longer. You need to store it in an airtight container
- Honey – Its low water content and ability to dehydrate the bacteria makes it spoilage-proof. With time it can crystallize but still edible and can run its container in a hot water to soften it up
- Sugar – Storing it in an airtight or vacuum-sealed container far from heat and light helps it last longer. However, if the sugar comes in contact with the moisture will be spoiled and be a ground for bacteria growth
- Salt – Its ability to dehydrate bacteria makes it last longer when kept properly
- Vinegar – Its acidic nature with the ability to drain bacterial helps it stay longer
- Powdered milk and more