How to preserve food raw materials to increase shelf life

Be it at home or in a food processing unit, we buy raw materials for making meals or a processed food. At home the quantity is less than in a food processing unit. Food raw materials are a susceptible to spoilage with time. It needs to withstand spoilage factors like enzymes or spoilage microbes. Water acts a major player in spoiling foods as well. The available water in foods increases the water activity and directly affects the shelf life of foods

Based on water activity, foods are of the following types:

i)               1. Low water activity foods(water activities (aw) below 0.6)

ii)              2.Medium water activity foods (water activity(aw) between 0.6 and 0.84)

iii)             3.High water activity foods (water activities (aw) between 0.84and 1.0)

The spoilage level depends upon the water activity level of the raw materials. Some of the methods used to

In Silos: Grains like wheat and rice need to remain dry to increase the shelf life for a longer period. Even a little bit of moisture in the form of humidity can cause it to form molds and grow bacteria and thereby degrade.

In Refrigeration: It is usually used for the preservation of vegetables that cannot be allowed to dry and at the same time need enough moisture to maintain the freshness. The temperature is regulated to serve the purpose. In-room temperature the vegetable may sustain for a day or two. In refrigerated condition, this shelf life is extended to three to seven days.

Cold chambers: Meat and seafoods are high water activity foods that get spoilt in a short duration.

Salting: Adding salt to food reduces the water availability to a minimum giving less to no water growth microbes.

Dehydration: Some foods need to reduce moisture content in order to stay for longer and need to be dehydrated by sun-drying or other drying methods.

Canning: Aseptically canning of foods prevents the growth of microbes. It can also involve pickling and canning foods.

Radiation: Foods are exposed to a certain amount of radiant energy which helps in controlling microbial growth.

Thermal methods: Processes like UHT and LTST ensures longer shelf life for fruit juices ad milk.

Non-thermal methods: Processes like HPP (High-Pressure Processing) ensure the properties o0of food are not lost due to heat.

Lemon: The use of lemon helps in the preservation of food. Lemon has citric acid which is acidic in nature that has natural antibacterial properties.

Smoking: Food subjected to smoke (for example pig meat) helps in forming certain chemicals that act as preservatives and add to the flavors as well.

Fermentation: Fermenting involves the use of a starter culture that has probiotic and prebiotic microbes helping in making tasty, delicious, and long-lasting recipes.

Vinegar: Vinegar or naturally available acetic acid acts as a preservative for foods for example in pickles.

Fumigation: In order to eradicate all the microbes and germs in the air, fumigation is done in storage areas at periodic intervals thereby reducing chances of spoilage.

Methods can also be used in combination to ensure food lasts for a long period.

The shelf life of raw material can also be preserved by covering it in shrink wraps while transportation. The hygiene of personnel working in a unit also affects the shelf life of the same. They must handle the food in a clean environment ensuring clean habits, clean clothes, headgear, gloves, and mask. Handling raw food to preserve for a longer time also involves use of sanitizers and soap for hand wash. The containers used to store the raw materials also must be hygienic to use. 

The racks and shelves used for keeping the raw material must be kept neat and free of dust and dirt to have clean raw material. Containers of food-grade must be used to pack raw paste and sauces. The pallets used to stack food raw material must be made of water resistant material like plastic. It has to be high enough so that water and dust from floor does not interfere with the food. Also in storage area, the pallets must be stacked 1m away from the wall so the dirt from walls are not attracted to the food. 

The flavoring agents like spices must be stored in air tight containers so that the aroma is not lost. The raw material storage area must be pest controlled to prevent invasion of rats and other pests. Ants are frequent visitors to raw material kept in go downs for long and need to be taken care of by disinfectants.