Pasteurization by sajib reza
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Pasteurization is a heating process used primarily on liquids like milk to kill pathogens while preserving flavor and nutritional value. The method was developed by Louis Pasteur and includes various techniques, such as Low Temperature Long Time (LTLT) and Ultra Heat Treatment (UHT), to extend shelf life and reduce spoilage. While it effectively reduces many harmful microorganisms, it does not eliminate all, thus decreasing the risk of diseases transmitted through milk.
Pasteurization by sajib reza
- 1. Pasteurization Md . sajib al reza Lecturer Nutrition And Dietetics College Of Nursing Science Dinajpur Dinajpur, Bangladesh Email: Sajib.Ftns2010@gmail.Com
- 2. pasteurization Pasteurization is a process of heating a food which is usually a liquid (milk) to a specific temperature for a predefined length of time and then immediately cooling it after it is removed from the heat to destroy any pathogens that may be present while causing minimal changes in the composition, flavor and nutritive value. Pasteurization of food is a preservation method in which moderately high (62°C to 100°C) temperatures are used (for about 15 to 30 minutes) to inactivate certain enzymes and kill certain other microorganism (such as those that cause tuberculosis), especially in milk. Since all pathogens are not killed at these temperatures. It was invented by French scientist Louis Pasteur during the nineteenth century. The process of pasteurisation involves heating milk to 71.7°C for at least 15 seconds. Once the milk has been heated, it is then cooled very quickly to less than 4°C.
- 3. Types of pasteurization method 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
- 4. Purpose of pasteurization ■ This process slow spoilage caused by microbial growth in the food. ■ Pasteurization is not killed all microorganisms in the food. Instead, it reduces the number of viable pathogens so they are unlikely to cause disease. ■ Pasteurization works to kill bacteria with high heat, ■ Helps to reduce the transmission of diseases such as typhoid fever, tuberculosis, scarlet fever, polio and dysentery. ■ Increase shelf life of milk.
- 5. methods of pasteurization There are four main methods of pasteurization of milk. These are: • 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. • 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.7
- 6. Continue …… • 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. • 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.
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- 10. 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 main: 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
- 11. CONTINUE • Infections primary to 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
- 12. 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.
- 13. Milk preservation: The common methods of preservation of milk are: • Boiling • Pasteurization • Sterilization • Drying • Freezing • Condensing • Preserve by chemicals
- 14. 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 •
- 15. THANK YOU