Determination of shelf life of foods

1. SHELF LIFE OF FOODS
A.Poshadri
Asst.Professor – Food Technology

2. Introduction
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.
Shelf Life is the period between manufacture and retail purchase of a
food product during which the product is of satisfactory quality.

3. Benefits of shelf Life studies
Operational Benefits
– Improve food safety aspects
– Increase risk management and reduce recalls
Marketing and Sales
– Support quality promises
– Support quality promises
– Avoid brand damage
Commercial benefits
– Enhance brand protection
– Establish extent of liability
• Avoid recall costs

4. Factors Affecting Shelf life

5. 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.
Shelf life indication on food
As per FSSAI regulations: “Use by” or “expiry” means the date,
which signifies the end of the estimated period under any stated
storage conditions, after which the product may not remain safe
and the food product probably will not have the quality of safety
attributes normally expected by the consumers and the food,
shall not be sold or distributed for human consumption

6. Best before date: means the date which
signifies the end of the period under any
stated storage conditions during which
the food product shall remain fully
marketable and shall retain any specific
qualities for which tacit or express
claims have been made, and beyond
that date, the food may still be perfectly
safe to consume, though, its quality may
have diminished. However the product
shall not be sold if any stage the
product become unsafe.

7. (i) the day, month and year using the DD/MM/YY format for
products with a short shelf life of up to 3 months;
(ii) the month and the year for products with a shelf life of more
The manner of declaration of date of manufacture or
packaging/Expiry/Use by/Best Before shall be as follows:
than three months, shall be declared in un-coded numerical
sequence except that the month shall be indicated by capital
letters and abbreviations (at least first three letters of the
month) may be used.

8. c) In addition to the expiry or Use by, any special conditions for the storage
of the food shall be declared on the label if the validity of the date depends
thereon. If required, storage conditions after opening the pack may also be
specified.
(d) Notwithstanding anything contained in this regulation, an indication of
the “Expiry” shall not be required for:
(i) Fresh fruits and vegetables, including potatoes which have not been peeled, cut or
similarly treated;
(ii) All types of wine;
(iii) Alcoholic beverages containing 10% or more by volume of alcohol;
(iv) Vinegar;
(v) Sugar boiled confectionery;
(vi) Food grade salt for industrial use;
(vii) Solid sugars;
(viii) Chewing gum and bubble gum.

9. Evaluation in a shelf life analysis
• The following common shelf life assessment tests will be conducted at regular
intervals to determine the shelf life of a particular foods.
Physico-Chemical analysis
• Physical changes/ Changes in properties of foods
• Moisture
• Acidity
• Salt content (In terms of Sodium chloride)
• Peroxide value (All fat rich and fried snacks)
• Free fatty acids
• Nutritional analysis
• Alcoholic acidity of food etc.,

10. Evaluation in a shelf life analysis
Organoleptic analysis/Sensory evaluation
• They following parameters will be checked at regular intervals through a trained
, semi trained panelists with the help of different sensory evaluation methods.
Microbiological analysis: It determine microbial growth, which leads to
the spoilage of a food product and the growth of microbial
the spoilage of a food product and the growth of microbial
pathogens that affect the safety of the product.
• Total plate count
• Yeast and mould count
• Aerobic microbial count
• Salmonella, E.coli, total coliforms and other bacterial pathogens

13. Shelf life analysis methods
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.
Shelf life analysis will be carried by storing the food at an accelerated
Shelf life analysis will be carried by storing the food at an accelerated
storage conditions using the concept of Q10.
• The concept of Q10: Q10 is the increase in the rate of the reaction
when the temperature is increased by 10 degrees centigrade (18°F).
E.g. If a food has a stability of 20 weeks at 20°C and 10 weeks at 30°C, thus
the Q10 will be 20/10

14. An accelerated shelf life assessment:
by increasing the storage temperature (38±1 and 80% RH)
(for long shelf life products)
Advantages of accelerated shelf life assessment
Advantages of accelerated shelf life assessment
R&D new Products
Time Sensitive introduction (Real time recommended as back
Up)

17. Shelf life analysis methods
Real Time shelf life testing – Food products are Stored under stated
or selected conditions for longer than the expected shelf life and
check at regular intervals to see when spoilage begins.

18. Conclusion…..
Shelf life of food vary with different food items, packaging,
storage, distribution etc.
Accelerated shelf life test (ASLT) and Real time are 2 methods for
calculation.
Sensory, physico-chemical, microbial analysis used to determine
shelf life.