**4. Food packaging as unit of food preservation technique**

Food packaging is undoubtedly, the engine of food industry instigating innovations in food preservation in an attempt to maintain the quality, nutritional values and sensory parameters of fresh or processed food products from the point of production to through the distribution channels to the dining tables of consumers. Although packaging of food started with containment of food to facilitate its safe distribution, it progressed with creating environment that discourage deteriorative and spoilage agents, hence the literature classified it as part of food preservation process. Food packaging is indeed a food preservation process since it contributes in the preservation of food products' quality and, guarantees food safety within the shelf-life [35]. Hence, the literature includes food preservation as one of the four major functions of food packaging [36]. Consideration of food packaging system as a preservative technique is based on the fact that packages function to protect products from spoilage and damage occasioned by environmental factors such as microbes, insects, light, heat, oxygen, water vapor,

odors, dirt, dusts, etc. [37]. Ganguly [38] convincingly aligned food packaging with food preservation process by stating that it delays deterioration/spoilage of the products, retains the beneficial effects of processing, extends shelf-life, and maintains or increases the quality and safety of food. To accomplish the forgoing, packaging shields food products from uncontrolled interaction with three major external elements which include; chemical, biological and physical environment. Chemical protection targets preventing or reducing compositional changes caused by environmental influences like exposure to gases (typically oxygen), moisture (gain or loss), or light (visible, IR or UV); physical protection ensures logistical efficiency as distortion of food products due to vibration, shock, compressive forces, poor handling (abrasion) etc. during distribution and transportation of the products. Also biological protection not only shields the products from incursion of microorganisms (pathogens and spoiling agents), insects, rodents, and other animals, thereby preventing disease and spoilage; it in addition create condition that regulate senescence (ripening and aging).

The potential of food packaging to preserve fresh or processed foods is explicable with the fact that the process creates different atmospheric environment around the products that discourage activities of agents of deterioration or spoilage. Food packaging as part of food preservation functions by preventing occurrences of undesirable changes in the wholesomeness, nutritive values or sensory quality of food products by shielding the food products from the undesirable activities of biological, chemical and physical agents of food deterioration/spoilage.

Food packaging facilitates storage or preservation of food products in small units and hence, increases the number of potential consumers that can patronize the products. Other instruments of preservation like the use of high or low temperature, for instance, are applicable through the packaging system/medium, as the direct contact of the products and the temperature's source may adversely affect the quality of the products.

Also, innovations in food preservations required to satisfy the dynamic change in the demands of consumers are achievable majorly through food packaging. Preservation of freshly harvested foods to take care of consumers desiring fresh foods, especially fruits and vegetables is being achieved by use of intelligent and active packaging technologies. This assertion is in agreement with the report of Tanja et al. [39] that considered food packaging as a way of improving food preservation system through elongation shelf-life of food. Major studies of improving food preservation are centred on developing new packaging technologies. Abdullahi [40] mentioned the development of smart packaging for optimization of shelf-life using nanotechnologies to prove predominating position of food packaging in efforts to improve food preservation. These new packaging technologies involving the use of biodegradable materials in the packaging system has enabled improvement in preservation of foods, especially, fruits and vegetables for sustainable environment [39]. Sarkar and Aparna [17] also allied advancement in food packaging; which threw up active packaging, aseptic packaging, smart packaging, bioactive packaging, edible packaging; with improvement in food preservation. They further stated that, by maintaining food standard at the highest possible degree, which may help in satisfying the needs of consumers throughout the food supply chain, food packaging incidentally prevents food spoilage/wastage.
