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Preservatives are the chemical agents which serve to retard, hinder or mask undesirable changes in food. More precisely, preservatives are substances when added to food to retard, inhibit or arrest the activity of microorganisms such as fermentation, acidification and decomposition of food or of masking any of the evidence of putrefaction but it does not include salt, sugar, vinegar, glycerol, alcohol, spices, essential oils etc.
According to Prevention of Food Adulteration (PFA) Act (1954) and Food Standards and Safety Act (FSSA) of 2006, a ‘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.
Preservatives may be anti-microbialpreservatives, which inhibit the growth of bacteria and fungi, or antioxidantssuch as oxygen absorbers, which inhibit the oxidation of food constituents. Common anti-microbial preservatives include calcium propionate, sodium nitrate, sodium nitrite and sulfites (sulfur dioxide, sodium bisulphite, potassium hydrogen sulphite, etc.) and ethylenediamine tetraacetic acid (EDTA). Antioxidants include butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT).
Sulphur dioxide (including sulphites) and benzoic acid (including benzoates) are among the principle preservatives used in the food processing industry.
Classes of preservatives
Under PFA (1954) and FSSA (2006), preservatives are classified into two classes Class I and Class II preservatives
Class I preservatives include mainly natural products which are used comparatively in higher concentrations than class II preservatives. There is no restriction to the addition of Class I preservatives to any food. For example- common salt, sugar, dextrose, spices, vinegar or acetic acid, honey, vegetable oils etc.
Class II preservatives are generally synthetic chemicals used in small quantities. Use of more than one class II preservatives is prohibited. For instance- benzoic acid and its salts, sulphur dioxide and the salts of sulphurous acid, nitrites and nitrates, sorbic acid and its salts, propionic acid and its salts, lactic acid and its salts, methyl or propyl parahydroxy benzoic acid, sodium diacetate are used.
The permitted usage levels of various chemical preservatives in different preserved food products are given in Table 1.
Table 1. Permitted usage levels of chemical preservatives in foods
| Chemical preservative
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Concentration (ppm)
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Foods
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| Sorbic acid and its salts (calculated as sorbic acid)
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50
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Nectars, ready to serve beverages in bottles/pouches selling through dispenser
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| 100
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Fruit juice concentrates with preservatives for conversion in juices, nectars for ready to serve beverages in bottles/ pouches selling through dispensers
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| 200
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Fruit juices (tin , bottles or pouches)
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| 500
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Jams, jellies, marmalades, preserve, crystallized glazed or candied fruits including candied peels fruit bars
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| Benzoic acid and its salts
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120
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Ready to serve beverages
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| 200
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Jam , marmalade, preserve canned cherry and fruit jelly
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| 250
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Pickles and chutneys made from fruits or vegetables
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| 600
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Squashes, crushes fruit syrups, cordials, fruit juices and barley water or to be used after dilution; Syrups and sherbets
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| 750
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Tomato and other sauces; Tomato puree and paste
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| Sulphur dioxide
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40
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Jam , marmalade, preserve canned cherry and fruit jelly
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| 150
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Crystallized glace or cured fruit (including candied peel)
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| 350
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Squashes, crushes fruit syrups, cordials, fruit juices and barley water or to be used after dilution; Syrups and sherbets; Fruit and fruit pulp
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| 2000
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Dehydrated vegetables
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| Sodium and/ or Potassium nitrite expressed as Sodium nitrite
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200
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Pickled meat
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| Lactic acid
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No limit
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Fermented meat, dairy and vegetable products, sauces and dressings, drinks.
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| Citric acid
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No limit
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Fruit juices; jams; other sugar preserves
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| Acetic acid
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No limit
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Vegetable pickles; other vegetable sauces, chutney
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Source: FSSA (2006) and Garg et al. (2010)
Benzoic Acid and Related Compounds
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Participants