Some foods can lose their nutritional value others cannot, let's take a look into this further.
You know if the label makes a claim on food value, let's say they manufacture some nutritious drink product and on that drink is some nutritional claim then let's say it has a shelf value of two years then at the end of the shelf life that product still needs to contain 100% of the vitamin C level.
It doesn't mean that when the product was manufactured it contained 100% of vitamin C and at the end of the shelf life it can contain half that level of vitamin C. What that means is that the manufacturer has to put an overage of that vitamin in the product because some of the vitamins will deteriorate over a period of time. Depending on the temperature of the storage of the product, usually the higher the temperature and the longer the storage time affects the rate of deterioration.
Vitamin C happens to be one of the most sensitive. The government does inspections on these products. They will randomly and routinely visit the food manufacturing companies. They will take samples and often times it is a surprise. What the food companies will do and the food scientist would do it when the product is formulated they will add an overage of vitamins and minerals but usually it's the vitamins. It protects the product during the shelf life.
What I am saying is that if they want the product to contain 100% of vitamin C at the end of the shelf life, then they may have to put in 200% to begin with because they know that 2 years later it will have lost half of its value.
Then what the food companies will do is have documentation on other food products that they have manufactured so they can protect the rate of loss. They can predict the rate of loss on similar products so that when a nutritional beverage is formulated they can base the level of any particular nutrient against historical values for similar foods.
Then that is the starting point and what they will do is enter the food into something called accelerated storage. That is a higher level of temperature so they can monitor the level of loss. They call that storage study. Most food companies will do that on their own accord but they do that in case there is ever a government inspection because they want to make sure they are meeting their label claim.
Companies that manufacture vitamins and minerals do the same thing. If it is a dry food like a vitamin tablet the rate of deterioration is usually much slower because it is a dry environment.
In a dry environment you don't get hydrolysis, which is the break down of a dry product compared to a liquid. The nutrients break down much faster in a liquid.
There is a whole host of different studies. When a product is placed in a storage study like that, not only do they access the nutritional properties of the food but also they have to know if the food is stable in other ways.
Like fats can oxidize. If you have ever had a bag of cake flour on your shelf in your kitchen and two or three years later it is full of weevils and you smell it and it has an awful smell, it is usually because the fat that is present in the flour has oxidized. The fat will break down into pre-fatty acids, which is not necessarily very good for you.
