Pasteurization

Food Science - Unit-4 - Milk and Milk Products - Pasteurization process.
Pasteurization or pasteurisation is a process in which packaged and non-packaged foods (milk and fruit juice) are treated with mild heat, usually to less than 100 °C (212 °F), to kill pathogens and extend shelf life.

1. Pasteur ization Dr.L.Gomathirajashyamala Department of Homescience Sri Bharathi Arts & Science College for Women Kaikkurichi - 622303

2. Introduction  Pasteurization is a process that kills microbes (mainly bacteria) in food and drink, such as milk, juice, canned food, and others.  Pasteurization involves heating food to a temperature that kills disease causing microorganism and substantially reduces the levels of spoilage organisms.  Pasteurization is not intended to kill all micro-organisms in the food.  Instead pasteurization aims to reduce the number of viable pathogens so they are unlikely to cause disease (assuming the pasteurized product is stored as indicated and consumed before its expiration date).  Heat also destroy enzymes that make milk spoil, so pasteurized milk drinkable for longer time. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 2

3. History  It was invented by French scientist Louis Pasteur during the 19 th century.  In 1864 Pasteur discovered that heating beer and wine was enough to kill most of the bacteria that caused spoilage, preventing these beverages from turning sour. The process achieves this by eliminating pathogenic microbes and lowering microbial numbers to prolong the quality of the beverage. Today, pasteurization is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 3

4. Objectives To Kill all the pathogens that may enter the milk & be transmitted to people. To Improve the keeping quality of milk. To Increase the shelf-life of products. To destroy microorganisms that would interfere with the activities of desirable organisms. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 4

5. Efficiency of Milk Pasteurization The % of reduction of numbers of microorganisms in milk depends on: Temperature of pasteurization. The holding time. The total number of microbial load that are spore formers or thermoduric organisms . 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 5

6. Methods of Pasteurization Milk Pasteurization: There are four common types of milk pasteurization that vary with temperature and time the milk is held at that temperature. Vat Pasteurization: High Temperature/Short Time (HTST) Ultra-pasteurization (UP) Ultra-High-Temperature (UHT) Other Methods (Used for other foods) Flash pasteurization Steam Pasteurization Irradiation Pasteurization 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 6

7. Four common types of pasteurization techniques used for pasteurizing milk are: Low Temperature Long Time (LTLT) – 63 °C / 145 °F for 30 minutes High Temperature Short Time (HTST) – 72 °C / 161 °F for 15 seconds Ultra-pasteurization (UP) - 138 ºC (280 ºF) for 2 seconds Ultra Heat Treatment (UHT) -- 140 °C / 284 °F for 1 to 4 seconds 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 7 M ethods of P asteurization

8. 1. Low Temperature Long Time (LTLT) / holder method/ Vat pasteurisation: A less conventional and typically for home pasteurization method is to heat milk at 63 °C (145 °F) for 30 minutes . It is then quickly cooled to 39 °C . 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 8

9. 2. High Temperature Short Time (HTST ): The process of pasteurisation involves heating milk to 71.7°C for at least 15 seconds. Then rapidly cooled to 10 °C. HTST milk is forced between metal plates or through pipes heated on the outside by hot water. It is a high-tech commercially used dairy pasteurization method. Milk simply labeled "pasteurized" is usually treated with the HTST method. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 9

10. 3. Ultra-pasteurization (UP ) The milk is heated to 138 ºC (280 ºF) for 2 seconds. Note this is above boiling, which means that high pressure must be applied to the milk to achieve this temperature, and is destructive to its nutritional quality. This method is used because it extends the refrigerated shelf-life of the milk to 60 - 90 days, and is the method of choice for national or regional milk brands because it allows time for warehousing and shipment of milk. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 10

11. 4. Ultra Heat Treatment (UHT): UHT , also known as ultra-heat-treating, processing holds the milk at a temperature of 140 °C (284 °F) for 4 seconds. This process lets consumers store milk for several months without refrigeration. Milk labeled "ultra-pasteurized" or simply "UHT" has been treated with the UHT method. Most commercial milk brands used this form of pasteurization since it is the quickest and cheapest. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 11

12. Temperature 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 12

13. Process …. ….. 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 13

14. Name of the milk borne diseases. Milk born disease: A joint FAO/WHO Expert Committee on milk hygiene classified milk borne diseases as under: Infections of animals that can be transmitted to Hu man : Primary importance: ☻ Tuberculosis ☻ Brucellosis ☻ Streptococcal infections ☻ Staphylococcal enterotoxin poisoning ☻ Salmonellosis ☻ Q fever Lesser importance: ☻ Cox-pox ☻ Foot and mouth disease ☻ Anthrax ☻ Leptospirosis ☻ Tick-borne encephalitis 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 14

15. C O N T I N U E … Infections primary to Hu man that can be transmitted through milk: ☻ Typhoid and paratyphoid fevers ☻ Shigellosis ☻ Cholera ☻ Enteropathogenic Escherichia coli Non-diarrhoeal diseases: ☻ Streptococcal infections ☻ Staphylococcal food poising ☻ Diphtheria ☻ Tuberculosis ☻ Entero viruses ☻ Viral hepatitis 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 15

16. Sources of milk infection: ☻ Water ☻ Infected animals ☻ Intestinal tract and feces ☻ Human handler ☻ Secreta and excreta (saliva, sneezing, coughing, stool, urine, etc.) of infected or carriers handlers. ☻ Environment e.g. contaminated vessel, polluted water, flies, dust, soil etc . 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 16

17. Other Methods (Used for other foods) Flash pasteurization used for drink boxes and other liquids that can be stored for long periods of time without refrigeration. This method involves high temperature for 3 to 15 seconds, followed by cooling and packaging. Very similar to UHT treatment of milk (see above). Steam Pasteurization used to kill E. coli, Salmonella and Listeria in beef carcasses. This results in surface temperatures of about 200° F. Irradiation Pasteurization used on such foods as meats (especially prepared meats, sausages and cold cuts), spices, and produce (such as almonds, etc ). The food is exposed to a type of radiation known as gamma rays 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 17

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19. Preservation of food is needed for: Food preservation adds variety to the food. Food preservation increases the shelf life of food. Food preservation increases the food supply. Food preservation decreases the wastage of food. Food preservation decreases dietary inadequacies. Food products last for a long period of time Food and vegetables are prevented from getting spoilt The color, test, and nutritive values of food is also preserved • 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 19

20. THANK YOU 1/17/2022 Milk Process - Pasteurization - Dr.L.Grs 20