Introduction to Chemical Preservatives

To understand preservatives, one should first know about food additives as preservatives are a type of food additive. Food additives are substances added to food to maintain or improve its safety, freshness, taste, texture, or appearance. The Joint FAO/WHO Expert Committee on Food Additives (JECFA), is the international body responsible for evaluating the safety of food additives. Only food additives that have been evaluated and deemed safe by JECFA, based on which the Codex Alimentarius Commission has established maximum use levels, can be used in foods that are traded internationally.

What FSSAI and Codex say about Food Additives!

Food additive is any substance not normally consumed as a food by itself and not normally used as a typical ingredient of the food, whether or not it has nutritive value, the intentional addition of which to food for a technological (including organoleptic) purpose in the manufacture, processing, preparation, treatment, packing, packaging, transport or holding of such food results, or may be reasonably expected to result (directly or indirectly), in it or its byproducts becoming a component of or otherwise affecting the characteristics of such foods. The term does not include contaminants or substances added to food for maintaining or improving nutritional qualities.

Food preservation is one of the methods to protect food from unwanted microbial growth. After the food is produced, product is store and protect by covering the rice and curry with lids to keep away flies and other insects. By this, we are protecting it from any infection caused by them. This is a short-term condition. Chemical food preservation, on the other hand, is done to preserve food for a longer time.

According to FSSAI “Preservative” means a substance which when added to food, is capable of inhibiting, retarding, or arresting the process of fermentation, acidification, or other decomposition of food.

 What is the difference between Food Additives and Food Preservatives?


Objective of food preservation

  1. Prevention of food by damaging agents like microbes, insect etc.
  2. Delay of enzymatic spoilage.
  3. Hinder or prevention of the growth of microorganism.

The above-mentioned objectives can be achieved by various techniques like drying, freezing, using preservatives etc.

Why chemical preservation?

  1. To preserve the natural characteristics of food.
  2. To preserve the way natural food looks.
  3. To increase the shelf life of foods for storage.

Types of Chemical Preservatives:

 According to the Canadian Food Inspection Agency (CFIA), preservatives are grouped into classes (I-IV), with each class having similar microbiological or chemical activity

 Class I: Curing preservatives in cheeses and meats

 Class II: Antimicrobials (which inhibit the activity or growth of microorganisms)

 Class III: Antifungals (which inhibit the activity or growth of yeast and mold) and

 Class IV: Antioxidants and its synergists (which are used to prevent the oxidation of vitamins, minerals and lipids of foods and ant browning agents which prevent both enzymatic and non-enzymatic browning of foodstuffs).

However, according to FSSAI Chemical preservatives are divided into two categories, namely:

  1. Class I Preservatives: Those which are obtained from natural sources.
  2. Class II Preservatives: Those that are obtained synthetically.


(A) Natural preservatives.

  1. How does salt preserve food?

Salt, when added not only imparts taste but also preserve food by creating an osmotic shock for microorganisms. Salts draws out water from the microorganism, making it shrunken, leading to death. In simple words, it works on the principle of osmosis.

According to some research, salt may limit oxygen solubility, interfere with cellular enzymes, or force cells to expend energy to exclude sodium ions from the cell, all of which can reduce growth rate.

  1. How does vinegar help in preservation?

Vinegar is a strong acid (acetic acid), and it lowers the pH of food materials when added, thus make the environment unsuitable for the growth of microorganism.


  1. Role of Sugar in preservation.

Sugar naturally preserves food by drawing out water and killing microorganisms and bacteria. Famous for preserving fruit, the high sugar content binds water and prohibits the growth of bacteria, mold, and yeasts.

  1. Does oil preserve food?

Yes, Atmospheric air contains moisture. This moisture aids in the growth of mold. Thus, oil is poured to block the air from meeting the food (e.g., pickling). This way, the pickle lasts for a long time without any growth of mold.

(B) Chemical Preservatives:

      Chemical preservation works either by interfering with cell membranes, enzyme activity, or alteration in the microorganism’s genetic mechanism.

           Following table describes every aspect of a chemical preservative.


Which stage is best to add preservatives?

Chemical Preservatives should be added just after the processing of food and before its packaging.


A suitable method of food preservation is one that slows down or prevents the action of the agents of spoilage altogether. Also, during the process of food preservation, the food should not be damaged. To achieve this, certain basic preservatives can be used. Nowadays Mostly all food products have food preservatives.  Chemicals are used as food preservatives as they are the most effective for longer shelf life and stop or delay bacteria’s growth and suppress the reaction when food meets oxygen. Some Chelating agents and antioxidants (Vitamin E, Vitamin C) work as preservatives, for example, Disodium ethylene diamine tetra-acetic acid (EDTA), Polyphosphates, Citric acid, and Ascorbic acid.

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