What is the aim of preserving food? Well to put it plainly is to prolong the shelf life whilst maintaining the flavour and customary texture of the food.
What preserving food essentially does is stem the natural progression of the biological destruction of the food, ever wondered why milk past its sell by date has a terrible odour? This is caused by huge amounts of exploding populations of micro-organisms contaminating the milk. So in a word throw it away immediately.
1. Take off The Water In The Food -
Much like any living thing, the microbes on your food need water to live. Take off the water then the bugs on your food will not survive and reproduce more bugs. This means your food is fresher for longer. This is achieved by exposing the food to the air and sunlight. Typical examples of these foods would be raisins, prunes and apricots. Foods can also be heated or smoked which essentially the same thing such as smoked salmon, ham and trout.
2. Controlling The number Of Air To Food -
As discussed previously just as those annoying microbes need water to survive they also need air. Nine times out of ten if you cut the number of air to food you cut the number of bacteria. For example if we cook some pasta and put it in the refrigerator, without thinking we put plastic wrap to cover it. We are essentially doing the above and prolonging its life. The most favorite version of this you would find is in your local store which is 'vacuum packaging'. This is done as it is an extremely effective way of removing all the air from the food they are commonly in the form of a glass jar or plastic bag.
3. Preserving With Chemicals -
There are at least twenty five chemicals which are designed as food preservatives to forestall your food from spoiling. The three most favorite and found in the majority of preserved foods are 'Mold Inhibitors' these slow down the growth of mold on bakery products such as calcium propionate, sodium propionate and sodium benzoate which is also used in cheese and dairy spreads to forestall mould growth. One of the most widely used and oldest is 'Salt' for example if you covered some beef with salt and left it for a integrate of days the salt would draw out all of the water whilst eradicating the bacteria living in the meat, next thing you know you have corned beef. This has been used widely for centuries by sailors and the formula is still used to this day by the military. Finally the remaining favourite are 'Acidifiers' microbes cannot withhold themselves in an acid environment so hence it is the exquisite retort to avoid spoilage. The most favorite used are vinegar, wine and citric acid. Also fruit have this natural preservative already.
4. Temperature -
Exposing your food to greatest heat for prolonged periods of time reduces the bacteria and kills the microbes that may otherwise be on your food. A good example of this would be milk, we have all heard of Uht milk (ultra high temperature) when milk has gone straight through pasteurization it is heated to almost 160 degrees for a short period of time so it destroys any bacteria and microbes. To note once you then open your carton of Uht milk and put in the refrigerator it can last a week as the cold environment prevents any bacteria organisms that may have survived the pasteurization process from reproducing more bacteria. Lastly one of the most favorite forms of preserving food in the modern world is 'Freezing' to give you an idea if you buy a leg of lamb from your local butcher and put it straight in your freezer it will keep for up to twelve months compared to that same leg of lamb being left in your refrigerator, it would then as a rule only last a week.
5. Irradiation -
This is a exact way of exposing food to electron beams or gamma radiation. These are high vigor beams that are stronger than X-rays. Gamma rays (sounds a a bit sci-fi I know) are designed to kill the living cells in food thus prolonging your foods shelf life. They work by destroying bacteria and insects on fruit, vegetables and wheat. For example by doing this it slows down the natural process that fruit ripens and stopping your potatoes from sprouting after a integrate of days. One of the big benefits of this food preservation is that it can stop diseases from certain organisms such as E.coli and listeria.
In up-to-date years with advent of the 'organic movement' you can purchase your fruit and vegetables without any of the above treatments and this is a preferred selection for many people these days, but you then have the problem of your fresh furnish spoiling sooner and a lot of critics do ask if there is a noticeable variation in taste between organic and non organic produce.
On the whole in this modern age we are fortunate adequate to live in, we have the luxury to select food that would not of otherwise been ready all year long for us to eat. Food processing does undoubtedly enhance our foods flavour and enriches the nutritional value of the food we buy for the needs of the buying public.
How is the Food You Buy Preserved? - Top Five Methods of Processing Foods Revealed
