
Sterilisation is the process by which all microorganisms are destroyed from food items, other substances, utensils & equipment, or surfaces, by using a sterilant such as a chemical and / or physical agents like high heat, high pressure, filtration or radiation to achieve sterility (CODEX: CAC/RCP 40-1993).
Pasteurisation is the process of heating foods such as milk & milk products, and alcoholic beverages like wine and beer to elevated temperatures for a sufficient period of time to kill microorganisms that are pathogenic and / or cause spoilage of food, without appreciably altering the taste of the food. Pasteurisation is named after Louis Pasteur, the French microbiologist, who invented the process in 1864.
Pasteurisation involves 3 commercial methods and 1 home method. These are briefly highlighted below, with the respective temperature and time requirements that need to be followed:
- HTST Pasteurisation: This is “high temperature, short time” or “flash heating”. In this commercial method, the milk is heated to 72 °C (162 °F) for 15 seconds.
- UHT Pasteurisation: This is “ultra-heat treatment”. In this commercial method, the milk is heated above 135 °C (275 °F) for 4 seconds.
- ESL Pasteurisation: Here, the milk is termed as “extended shelf-life” This commercial method involves filtration as well as heat-treatment, below 135 °C (275 °F).
- Home Pasteurisation: Pasteurisation at home is very popular in India, especially in rural areas, where the raw milk, freshly milked from the cows is supplied to homes by traditional milk vendors. In this method, the milk should be heated to 63 °C (145 °F) for 30 minutes.
Table 1: Difference between sterilisation and pasteurisation
Sterilisation | Pasteurisation |
---|---|
Kills all microorganisms | Kills viable pathogens that may cause disease and / or spoilage of food |
Chemical agents and / or physical agents (heat, pressure, filtration, radiation) are involved | Only heat is involved |
Can adversely alter the taste of the food | Does not appreciably alter the taste of the food items |
Non-food items can also be subjected to sterilisation | Only limited number of food-items can be subjected to pasteurisation |
What does FSSAI Say about Sterilisation?
The Food Safety & Standards (Food Products Standards and Food Additives) Regulations, 2011, indicates that:
- The term “Sterilisation” when used in association with milk, means heating milk in sealed container continuously to a temperature of either 115 °C (239 °F) for 15 minutes or at least 130 °C (266 °F) for a period of 1 second or more in a continuous flow and then packed under aseptic condition in hermetically sealed containers to ensure preservation at room temperature for a period not less than 15 days from the date of manufacture.
- Flavoured milk may be made from milk from cows, goats, sheep or a mixture of any of these. It may be of various types like standardized milk, recombined milk, toned milk, double toned milk, or skimmed milk. It may contain nuts (whole, fragmented or ground), chocolate, coffee or any other edible flavour, edible food colours and cane sugar. Flavoured milk should be pasteurised, sterilised or boiled. The type of milk used should be mentioned on the label.
- Cream including sterilised cream, is produced from cow or buffalo milk or a combination thereof. It should be free from starch and other ingredients foreign to milk.
- Frozen curried vegetables / ready-to-eat vegetables are prepared from fresh, dehydrated or frozen or previously processed vegetables, legumes, cereals or pulses, whether whole or cut into pieces. These are cooked by standard methods, followed by thermal sterilisation and freezing at – 18°C, before packaging.
- Canned finfish, shrimp, sardines, salmon, crab meat, tuna and bonito shall be packed in hermetically sealed clean and sound containers and subjected to adequate heat treatment (100 °C for more than 120 minutes) followed by rapid cooling to ensure commercial sterility.
- Natural Mineral Water: The transport of natural mineral water in bulk containers for packaging or for any other process before packaging is prohibited. Natural mineral water shall be packaged in clean and sterile containers.
- Dairy based drinks, flavoured and or fermented (e.g. chocolate milk) cocoa, or eggnog should be sterilised by UHT, and should have a shelf-life more than three months.
- Monosodium glutamate is not allowed in sterilized cream.
The Food Safety & Standards (Packaging and Labelling) Regulations, 2011, indicates that:
- A batch number or code number or lot number which is a mark of identification by which the food can be traced to the manufacturer and identified in the distribution, shall be given on the label for sterilised milk.
- In case of package or bottle containing sterilised milk, soya milk or flavoured milk, the declaration should be made as follows:
“BEST BEFORE ……….DATE/MONTH/YEAR”
OR
“BEST BEFORE……..DAYS FROM PACKAGING”
OR
“BEST BEFORE …….. DAYS FROM MANUFACTURE”
- In the case of condensed milk / condensed skimmed milk (unsweetened) sterilised by Ultra High Temperature (UHT) treatment:
This has been sterilised by UHT Process
- Irradiated foods: The label of a food, which has been treated with ionising radiation, shall carry a written statement indicating the treatment in close proximity to the name of the food. In addition all packages of irradiated food shall bear the following declaration and logo, namely:
PROCESSED BY IRRADIATION METHOD DATE OF IRRADIATION……………… |
LICENSE NO of Irradiation Unit……………………………….. PURPOSE OF IRRADIATION………………… |
- Packaged drinking water and packaged mineral water should be packaged in sterile bottles / containers.
What does FSSAI Say about Pasteurisation?
The Food Safety & Standards (Food Products Standards and Food Additives) Regulations, 2011, indicates that:
- The terms “Pasteurisation”, “Pasteurised” and similar terms shall be taken to refer to the process of heating milk of different classes to at least 63 °C and holding at such temperature continuously for at least 30 minutes or heating it to at least 71.5 °C and holding at such temperature continuously for at least 15 seconds or an approved temperature time combination that will serve to give a negative Phosphatase Test. All pasteurised milk of different classes shall be cooled immediately to a temperature of 10 °C, or less.
- Toned milk, double toned milk, flavoured milk, full cream milk, recombined milk, standardised milk from cow, buffalo, goat or sheep should be pasteurised.
The following products should be made from pasteurised milk:
- Dahi or curd.
- Cheddar cheese, Danbo cheese, Edam cheese, Cottage cheese & Creamed cottage cheese, and Cream cheese (Rahmfrischkase).
- Ice cream, Kulfi, Chocolate ice cream or Softy ice cream.
- Frozen dessert / Frozen confection.
- Milk ice or Milk lolly.
- Table butter.
- Chakka & Shrikhand.
- Yoghurt.
- Ice candy should be made by freezing a pasteurised mix prepared from a mixture of water, nutritive sweeteners e.g. sugar, dextrose, liquid glucose, dried liquid glucose, honey, fruits and fruit products, coffee, cocoa, ginger, nuts, salt, and permitted food additives.
- Monosodium glutamate is not permitted in pasteurised cream.
- Canned or bottled fruit nectar should be pasteurised.
The Food Safety & Standards (Packaging and Labelling) Regulations, 2011, indicates that:
- Pasteurised milk may be denoted by the letter ‘P’; followed by the class of milk. For example Pasteurised Buffalo milk shall bear the letters ‘PB’.
omisore adekunle says
I need more information about dairy products
omisore adekunle says
what are the factors to put in consideration when food and chemicals labelling requirements