SHELF LIFE OF FOOD

Shelf-life

• Time during which the food product will: remain safe; retain desired sensory, chemical, physical and microbiological characteristics; comply with any label declaration of nutritional data, when stored under the recommended conditions

• It begins from the time the food is finished processing and packaged.

Factors Affecting Shelf life

Intrinsic Factors               Extrinsic Factors

Water Activity                    Time–temperature profile during processing; pressure in the headspace

pH                                           Temperature control during storage

Redox potential (Eh)        Relative humidity (RH)
Available oxygen                Exposure to light (UV and IR)
Nutrients                               Environmental microbial counts during

Natural microflora and surviving microbiological counts   Composition of atmosphere within packaging.

Use of preservatives in product formulation  Subsequent heat treatment

Shelf life indication on food

• Use by date – foods that have a use by date are generally regarded as unsafe to eat after the designated date because a build-up of bad bacteria may have occurred – even if the food in question still looks and smells good enough to consume.

• It is about safety

• Best Before – It signifies that although the date on the package may have passed, the product is still safe to consume on the proviso the item has been stored according to instructions, while still generally maintaining its colour, texture and flavour.

• It is about quality of food.

Methods

1. Accelerated shelf-life testing – The food product is conditioned and stored at elevated temperature and/or humidity and the quality changes of the product are evaluated at a specific sampling rate.

• It can be two to four times faster than the real shelf life study.

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