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 access roads to farm centres, or 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 raw food materials as produced 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, Edo, Ekiti, Osun and Ondo to find heaps of fruits like oranges, grapes,pine apple and bananas rotting away at the rural farms due tolack of processing knowhow.
The various Ministries of agriculture at the state and federal level should therefore, put in place measures that would reduce post harvest losses by providing the enabling environment. It is 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.
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. It 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.
The different scientific methods of food preservation:
Preservation usually involves preventing the growth of bacteria, fungi (such as yeasts), and othermicro-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 foodpreservation, 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
Freezingis 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 asmalt 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 withfire.
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. 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 obligateanaerobe 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.
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.
