If you knew exactly what went into your packaged food or knew about the storage conditions before it reached your kitchen, chances are that packaged food companies would go bankrupt.
Here's us not trying to bankrupt those companies, just imparting some common knowledge so that you can safeguard your health & happiness.
Focusing only on the ingredients -
Only quality ingredients are not enough to make food healthy or nutritious. Packaged food travels distance to reach you and is exposed to light. The exposure of food to light can result in the photodegradation (or spoilage) of food products. The photodegradation usually occurs in food constituents, such as fats, proteins, and vitamins resulting in discoloration, off-flavor and loss of nutrition. Most food products when exposed to light loses its nutritional value over a period of few weeks, so older the food chances are it is already devoid of all the good nutrients you are buying it for.
Ignoring the storage temperature conditions -
Packaged food products are often transported over long distances, stored in warehouses and are then left to sit on store shelves for months before you purchase exposing itself to different temperature conditions. When food is exposed to varied temperature conditions and excessive heat for prolonged periods, it leads to natural food enzyme reactions, that can result in loss of essential vitamins, nutrients and food decay.
Swearing by Best Before Date/Expiry Date/Use by Date -
Expiry/Use by Dates date are just an indicator of the food life and is not a full proof method to determine the safety of the product. Food life depends on various factors, with the most important being how it is stored before it reaches you. Most natural food products are suggested to be stored in a cool and dry place, which means temperature conditions of less than 25 degree Celsius. If you are living in Hot & Humid country, chances are that these conditions are not met for prolonged period. Food spoilage can easily be determined by the change in a food’s normal state and can be visibly detected if packs are puffed. In absence of obvious visible changes such as puffed packs, discoloration, smell or taste can help.