The imperative of food preservation

One of the critical issues to be addressed towards meeting the ever increasing demands of food security is that of preservation. Several researches have shown that in many countries where there are no good roads, stable electric power supply, adequate water and application of relevant technology to support preservation there is a lot of post harvest losses. There may be enough food for everyone but theses critical factors could lead to food insecurity. Nigeria is no exception.

For instance, it is not unusual in states such as Benue and Ondo to find heaps of fruits like oranges, grapes, pine apple and bananas rotting away at the rural farms due to lack of processing knowhow.

The various Ministries of agriculture at the state and federal level should putt in place measures that would reduce post harvest losses by providing the enabling environment. And also by engaging in massive human capital development through farm extension workers who should be graduates in the field of agriculture and related disciplines. There should also be the upgrading of local food preservation methods adaptable to their immediate needs.

For instance, many local farmers may not be aware of some relevant research findings in this regard. A Nigerian teacher, Mohammed Bah Abba has invented a cooling system with the capacity to preserve perishable food in climates that lack sufficient water or rainfall. His motivation was out of concern for the rural poor and by a deep interest in using indigenous African technology to develop practical, local solutions to rural problems.

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His “pot-in-pot” cooling system is based on a simple physical principle that was even in use in ancient Egypt. It is simple, affordable and made form local materials. A clay pot is filled with wet sand, which is kept moist. A second smaller pot, is placed into the wet sand in the bigger pot, which is then covered with a damp cloth. As the water in the sand evaporates, it drops the temperature, and cools the inner pot.

The invention that has been made public since 2009 is expected to have a significant impact in Nigerian villages and even allows young girls to attend school since they don’t have to hawk food every day. It also increases family income and helps to reduce disease.

The truth however, is that a lot more still needs to be done for mass public enlightenment. The more farmers who are aware and deploy such local technology the better for Nigeria’s food security. Home makers too need to know what they could do to preserve some basic food items they are not going to cook immediately. In addition, the issue of food preservation should not be left to the government alone. The private sector has to come in.

According to the Brand Manager, Stallion Motors, Mr. Prashant Sinha recent findings have also revealed that about 70 per cent of what farmers in the country produce is usually lost between the farmlands and the markets due to the absence of a good transportation system. He made this statement in Abuja when Stallion Motors Limited moved to reduce post-harvest losses associated with agricultural products, as it unveiled a scheme that would enable it to distribute 316 pick-up vans to farmers.

Each truck, according to Sinha, is valued at N2.28m and will be given to farmers at a discounted rate of 40 per cent. He said the move was part of efforts aimed at assisting the Federal Government to achieve its agriculture transformation agenda.

Part of the aims of the agenda is to add 20 million metric tonnes of food to the domestic food supply chain by 2015, as well as increase the contribution of the agricultural sector to the nation’s Gross Domestic Product. Sinha said apart from helping young farmers embrace mechanisation, the scheme would also help change the face of agri-business.

He, however, expressed optimism that with the new initiative, the anomaly would be corrected. Sinha said, “This promises to change the fortunes of farmers and improve the way they farm, and chart a new horizon for agro business in Nigeria. There is no gainsaying that the surest way to transform a nation is to first help it become sufficient in food production.

“We need to move a little faster to catch up with modern agriculture, and if we must make agro business attractive, especially to the younger generation, we must constantly improve the way we farm and embrace mechanisation.”

The different scientific methods of food preservation

Preservation usually involves preventing the growth of bacteria, fungi (such as yeasts), and other micro-organisms (although some methods work by introducing benign bacteria, or fungi to the food), as well as retarding the oxidation of fats which cause rancidity. Food preservation can also include processes which inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut, which can occur during food preparation.

Many processes designed to preserve food will involve a number of food preservation methods. Preserving fruit by turning it into jam, for example, involves boiling (to reduce the fruit’s moisture content and to kill bacteria, yeasts, etc.), sugaring (to prevent their re-growth) and sealing within an airtight jar (to prevent recontamination). There are many traditional methods of preserving food that limit the energy inputs and reduce carbon footprint.

Maintaining or creating nutritional value, texture and flavour is an important aspect of food preservation, although, historically, some methods drastically altered the character of the food being preserved. In many cases these changes have now come to be seen as desirable qualities – cheese, yoghurt and pickled onions being common examples.

Drying

Drying is one of the most ancient food preservation techniques, which reduces water activity sufficiently to prevent bacterial growth.

Refrigeration

Refrigeration preserves food by slowing down the growth and reproduction of micro-organisms and the action of enzymes which cause food to rot. The introduction of commercial and domestic refrigerators drastically improved the diets of many in the Western world by allowing foods such as fresh fruit, salads and dairy products to be stored safely for longer periods, particularly during warm weather.

Freezing

Freezing is also one of the most commonly used processes commercially and domestically for preserving a very wide range of food including prepared food stuffs which would not have required freezing in their unprepared state. For example, potato waffles are stored in the freezer, but potatoes themselves require only a cool dark place to ensure many months’ storage. Cold stores provide large volume, long-term storage for strategic food stocks held in case of national emergency in many countries.

Smoking is used to lengthen the shelf life of perishable food items. This effect is achieved by exposing the food to smoke from burning plant materials such as wood. Most commonly subjected to this method of food preservation are meats and fish that have undergone curing. Fruits and vegetables like paprika, cheeses, spices, and ingredients for making drinks such as malt and tea leaves are also smoked, but mainly for cooking or flavoring them. It is one of the oldest food preservation methods, which probably arose after the development of cooking with fire.

Artificial food additives

Preservative food additives can be antimicrobial; which inhibit the growth of bacteria or fungi, including mold, or antioxidant; such as oxygen absorbers, which inhibit the oxidation of food constituents. Common antimicrobial preservatives include calcium propionate, sodium nitrate, sodium nitrite, sulfites (sulfur dioxide, sodium bisulfite, potassium hydrogen sulfite, etc.) and disodium EDTA. Antioxidants include BHA and BHT. Other preservatives include formaldehyde (usually in solution), glutaraldehyde (kills insects), ethanol and methylchloroisothiazolinone.

Canning and bottling

Canning involves cooking food, sealing it in sterile cans or jars, and boiling the containers to kill or weaken any remaining bacteria as a form of sterilization. It was invented by Nicolas Appert.[2] Foods have varying degrees of natural protection against spoilage and may require that the final step occur in a pressure cooker. High-acid fruits like strawberries require no preservatives to can and only a short boiling cycle, whereas marginal fruits such as tomatoes require longer boiling and addition of other acidic elements. Low acid foods, such as vegetables and meats require pressure canning. Food preserved by canning or bottling is at immediate risk of spoilage once the can or bottle has been opened.

Lack of quality control in the canning process may allow ingress of water or micro-organisms. Most such failures are rapidly detected as decomposition within the can causes gas production and the can will swell or burst. However, there have been examples of poor manufacture (underprocessing) and poor hygiene allowing contamination of canned food by the obligate anaerobe Clostridium botulinum, which produces an acute toxin within the food, leading to severe illness or death. This organism produces no gas or obvious taste and remains undetected by taste or smell. Its toxin is denatured by cooking, though. Cooked mushrooms, handled poorly and then canned, can support the growth of Staphylococcus aureus, which produces a toxin that is not destroyed by canning or subsequent reheating.

Some foods, such as many cheeses, wines, and beers will keep for a long time because their production uses specific micro-organisms that combat spoilage from other less benign organisms. These micro-organisms keep pathogens in check by creating an environment toxic for themselves and other micro-organisms by producing acid or alcohol. Starter micro-organisms, salt, hops, controlled (usually cool) temperatures, controlled (usually low) levels of oxygen and/or other methods are used to create the specific controlled conditions that will support the desirable organisms that produce food fit for human consumption.

Mass public enlightenment on the methods, mechanisms and adaptation of these preservation methods has become imperative towards achieving national food security, starting from the rural areas.