Imagine how life would be if you didn’t have to worry about your bread getting spoilt or stale if you left it open for days on end. Imagine if it was an everlasting bread. And imagine this: if there were no refrigerators to keep our food and stew from spoiling, what would we do to preserve them?
Ask yourself this: our ancient forefathers had no fridges, silos or smoking kilns: how then did they preserve their food?
It is common knowledge that agricultural products are perishable. Today, one of the biggest challenges facing many farmers and agricultural experts is how to preserve their products after harvesting and before they get sold. Many farm products like food and dairy products have a short lifespan, placing a demand on the farmers to sell off their produce not long after they are harvested. The two most common causes of food spoilage are exposure to moisture and exposure to air. Either of these factors is capable of facilitating the growth of microorganisms, which eventually causes the food substance to decay.
Remember the adage which says, “Cast your bread on the waters, and you shall find it after many days”? Well, the statement is partly true and partly false. It is true because you shall most surely find your bread again, but it is false because you will find it in a different form. The water (remember exposure to moisture) would have triggered and facilitated several reactions on the bread, and when you find it again you will most likely find other microorganisms growing on it – especially fungi and molds. For this reason, food manufacturers have sought out and developed innovative techniques for preserving food, so that the shelf-life is extended, and the quality is not diminished.
The most popular preservation techniques are Drying, Salting, Use of Silos, Refrigerating, Use of Barns, and etcetera. The choice of preservation technique is largely defined by the nature of food substances being processed. Some techniques are expensive to set up, while some others are relatively cheap, simple and easy.
Profitability is also a key factor for determining what preservation technique to make use of. For instance, if your estimated sales from your harvest is around $500, or NGN 180,000, and the cost of setting up a silo (for instance) is $550 or NGN 200,000, wisdom demands that you review your plans and search out viable alternatives, in order to avoid recording losses in your business.
These two factors – the nature of the farm product and the outcome of the cost-profit analysis – are therefore critical to deciding on a preservation technique.
The following are the principles upon which preservation techniques are based:
- Reduction of water/moisture content
- Manipulation of temperature to preserve the quality
- Inhibition of the microbial activity
Common preservation techniques:
Drying involves the systematic elimination or reduction of water from the farm products to avoid spoilage due to microbial activity. The farm products to be dried are typically placed on a clean, flat surface (like a mat or tray) and kept under direct sunlight to dry. Food products like cowpea, melon, pepper, meats, roots, fruits, crayfish and several kinds of cereal are often sun-dried.
This is one of the most popular traditional techniques for preserving fish in West Africa. Even though it is quite primitive, it is still very effective at preserving the quality of fish and increasing its shelf-life. While modern smoking kilns have been developed and are being used, it is still possible to smoke fish without a modern kiln. Simply make a mud oven or container, get some fire in it, and place wire gauze over the top of the kiln. Place the fish on the wire gauze and let the smoke of the firework on it. It is advisable to turn the fish frequently to prevent burning. The smoke of the fire adds a unique flavor and aroma to the fish, while also inhibiting microbial growth on the fish.
Food items like fruits and vegetables are most prone to spoilage, due to their high moisture content. Now, while some cereals, fish and certain legumes can be preserved via smoking and/or drying, several other food types cannot. For instance, fruits are best stored in a refrigerator, at a temperature that is lower than the room temperature. Microbial activity is temperature specific, and would most likely thrive at room temperature. Therefore, by keeping the fruits and vegetables at a temperature that is below room temperature, the tendency of spoilage is eliminated, and potential microbial activity is hindered. However, it is worthy to note that refrigeration is quite an expensive preservation technique, and it costs quite a lot of resources to the main. For a country like Nigeria, think about the cost of getting a refrigerator, cost of electricity (which is far from being constant), cost of the generator, cost of fuel, and etcetera. The point here is this: while refrigeration is effective, it is not economically viable. It will however not be discouraged.
These three techniques here mentioned are only a handful of the many preservation techniques that are available and being used for preserving farm products. Use of silos, barns, and other methods are equally important and relevant for the preservation of food. Many people cite the use of chemicals as an affordable and effective means of preservation. While the proponents of this narrative may not be too far from the truth, the fact is that the story doesn’t end at the point of the effectiveness of chemicals in food preservation. Scientific research has proven that the increased use of chemicals in food preservation predisposes consumers to the risk of developing a wide range of acute and chronic illnesses, most notably, certain types of cancers and bowel disorders. While food manufacturers add chemicals to their products to increase their shelf life, the chemicals form toxic compounds which are eventually ingested along with the food.
So, when next you consider using chemicals for food preservation, think of the unhealthy outcomes you may be predisposing your consumers to. One thing is clear: the use of chemicals in preservation is not healthy.