Food (for the scope of this article, vegetarian only) goes bad as a result of exposure to open air (also called oxidation). The air we breathe contains a number of microorganisms (or bacteria) who, when directly exposed to food cause decay over a period of time. Most food, vegetables and fresh raw material can retain their freshness and nutrition for approx 6-14 hours when kept at room temperatu
The bacteria that cause food decay ideally survive between 5C to 60C. Below 5C and beyond 60C are ranges where harsh conditions neutralise them upto 99.7%. Similar approach, when applied to preserving food can be observed and implemented as below.
Gravies being cooked are roughly at a temperature range of 65C-80C, i.e. bacteria free. Now the essence of longer shelf life lies in avoiding interaction with air while packing and preserving it. For households, this can be done by transferring the hot (freshly cooked) food into thermal resistant vacuum containers and placing it the “freezer” section of the refrigerator to cool down. The freezer section roughly operates within the range of -2C to -20C.
Upon cooling (hardening like bricks), the thermal container can be packed air-tight and placed within the freezer itself. This process, for households can retain freshness of food for over a month. The food preserved as such, can be taken out whenever needed, thawed/heated and enjoyed.
An important fact to adhere to here, is not to refreeze the food once thawed, heated or exposed to open air.
On similar lines, the Ready-To-Eat Frozen food manufactures employ a concept called Blast Freezing, which is ideally a scientific, error free and commercially viable version of the process discussed above. For obvious reasons, the expected shelf life, quality benchmarks and microbiological checks are much more stringent for commercial manufacturers. Blast freezing, coupled with suitable (cold) storage and supply chain provides them, just that.
For more on Blast Freezing and Commercial Food Preservation, stay tuned for the next blog…