Preservation of milk and milk products refers to the methods and techniques used to prevent or slow down the spoilage and deterioration of these products, thereby extending their shelf life and maintaining their quality and safety. Preservation methods aim to inhibit or control the growth of microorganisms, enzymes, and other factors that can lead to spoilage and foodborne illnesses.
A. Heat treatment methods for Preservation of Milk and Milk Products
- Thermisation is a milk preservation method that involves heating milk to a moderate temperature range of 57-68°C (135-155°F) for a short duration of 15-20 seconds, followed by rapid cooling to below 6°C (43°F). This technique is commonly used in the dairy industry to extend the shelf life of milk and inhibit the growth of spoilage-causing bacteria.
- The primary aim of thermisation is to reduce the population of psychrotrophic bacteria, which are microorganisms capable of growing at refrigeration temperatures. These bacteria are often responsible for milk spoilage and can contribute to off-flavors and decreased product quality. By subjecting milk to mild heat treatment during thermisation, the growth of psychrotrophic bacteria is suppressed, leading to an extended shelf life for the product.
- It’s important to note that thermisation is not a sterilization process. While it effectively controls spoilage bacteria, it does not eliminate all microorganisms present in the milk, including potential pathogens such as Listeria monocytogenes. Therefore, thermised milk should still be handled and stored properly to ensure food safety.
- Thermisation offers a balance between the benefits of extended shelf life and improved microbial quality while retaining the nutritional value and sensory characteristics of milk. The method is widely employed in the production of various dairy products, including pasteurized milk, yogurts, and cheeses.
- In summary, thermisation is a milk preservation technique that involves mild heating of milk to reduce the population of psychrotrophic bacteria and extend the shelf life of the product. It provides a compromise between heat treatment and the retention of desirable qualities in milk, making it a valuable tool in the dairy industry.
Pasteurization is a widely used method of food preservation, including the treatment of milk, that involves heating the product to a specific temperature for a defined period of time. The primary goal of pasteurization is to reduce the number of viable pathogens and spoilage-causing microorganisms present in the milk, thus improving its safety and extending its shelf life.
Various types of pasteurization methods are employed in the dairy industry, differing in temperature and duration of heat treatment. These methods include:
- Vat Pasteurization/Low temperature, long-time pasteurization: In this method, milk is heated at 63°C (145°F) for 30 minutes. It is a relatively gentle process that helps to retain the natural flavor and nutritional properties of the milk.
- High Temperature/Short Time (HTST) pasteurization: In HTST pasteurization, milk is rapidly heated to a temperature of 72°C (161°F) for 15 seconds, followed by rapid cooling. This method is more commonly used in commercial milk processing due to its efficiency and effectiveness in eliminating harmful microorganisms.
- Ultra-pasteurization (UP): Ultra-pasteurization involves heating milk at even higher temperatures, typically ranging from 138°C to 150°C (280°F to 302°F), for one or two seconds. This process helps to extend the shelf life of milk, allowing it to be stored at room temperature without refrigeration until opened.
- Ultra-High-Temperature (UHT) pasteurization: UHT pasteurization subjects milk to extremely high temperatures of around 280°F (138°C) for only two seconds. This process effectively kills bacteria and spores, ensuring the milk remains sterile when packaged in aseptic containers. UHT milk can be stored at room temperature for an extended period until opened.
The objectives of pasteurization include:
- Destruction of pathogenic organisms: Pasteurization eliminates or significantly reduces the number of pathogenic bacteria present in milk, such as Coxiella burnetii, Brucella abortus, Mycobacterium tuberculosis, and others, making the milk safer for consumption.
- Maintenance of milk quality: By reducing the microbial load, pasteurization helps maintain the quality of milk and milk products, including flavor, texture, and nutritional composition.
- Elimination of unwanted organisms: The process of pasteurization targets and eliminates unwanted microorganisms that can cause spoilage and affect the sensory characteristics of milk.
Overall, pasteurization plays a critical role in ensuring the safety and quality of milk and milk products, protecting consumers from harmful pathogens while preserving the desirable attributes of the product.
3. Sterilization or UHT
Sterilization, also known as Ultra-High-Temperature (UHT) treatment, is a method of food preservation that involves subjecting the product to high temperatures, typically above 100°C (212°F), for a specific time to eliminate or destroy almost all microorganisms, including bacteria, yeasts, molds, and their spores. The sterilized product is then packaged in air-tight containers, either before or after the heat treatment, to maintain its sterility and extend its shelf life without the need for refrigeration.
There are two commonly used methods of sterilization in the dairy industry:
- Conventional or In-bottle sterilization: In this method, the product, such as milk, is packaged in bottles or containers before undergoing heat treatment. The packaged product is then heated at temperatures of 105-110°C (221-230°F) for 30-45 minutes. This prolonged exposure to high temperatures ensures the destruction of both vegetative cells and spores of microorganisms, resulting in a commercially sterile product. The sterilized milk can be stored at room temperature for an extended period until opened.
- UHT or Aseptic method: The UHT method involves rapidly heating the product, such as milk, at temperatures ranging from 135-150°C (275-302°F) for a short period of time, typically 1-20 seconds. This rapid heat treatment effectively kills or inactivates microorganisms present in the milk, including both vegetative cells and spores. The milk is then instantly aseptically filled into sterile containers, ensuring that it remains sterile throughout its shelf life. UHT-treated milk can be stored at room temperature without refrigeration until opened, providing convenience and extended shelf life.
The objectives of sterilization include:
- Ensuring the quality of milk and milk products at room temperature: Sterilization eliminates the presence of viable microorganisms, including pathogenic and spoilage-causing organisms, ensuring the safety and quality of the product without the need for refrigerated storage.
- Destruction of microorganisms: Sterilization targets a wide range of microorganisms, including vegetative cells, spores, and viruses, ensuring their complete destruction or inactivation, thus minimizing the risk of foodborne illnesses and spoilage.
Sterilization is an important method in the dairy industry to produce commercially sterile products that can be safely stored and consumed at room temperature. It provides convenience to consumers while maintaining the nutritional quality and sensory attributes of milk and milk products.
Dehydration is a method of milk preservation that involves the removal of water from milk through the application of heat under controlled conditions. By reducing the water activity, dehydration inhibits the growth of spoilage-causing microorganisms and extends the shelf life of milk. Additionally, dehydration reduces the volume and weight of milk without compromising its nutritive value.
The objectives of dehydration in milk preservation are:
- Microbial control: By removing water, dehydration creates an environment that is less conducive to the growth of spoilage-causing and pathogenic microorganisms. This helps to extend the shelf life of milk by reducing the risk of microbial spoilage.
- Shelf life extension: Dehydration increases the stability of milk by reducing its water content, thereby minimizing the potential for chemical reactions and enzyme activity that can lead to spoilage. This helps to extend the product’s shelf life and maintain its quality over an extended period.
There are various methods of dehydration used in milk preservation, including:
- Spray-drying: In this process, the pre-concentrated liquid milk is sprayed into a stream of hot gas, resulting in rapid evaporation of the water content. The milk droplets are transformed into fine powder particles, which are then collected. Spray-drying is widely used in the production of powdered milk and milk-based ingredients.
- Drum drying: This method involves applying a thin film of pre-concentrated milk onto the outer surface of a heated rotating drum. As the drum rotates, the milk film is dried by the heat, forming a sheet of dried milk that is scraped off the drum surface and subsequently processed into flakes or powdered form.
- Fluid bed drying: Fluid bed drying is a versatile process that involves the drying, cooling, agglomeration, granulation, and coating of particulate materials. In this method, a gas, usually air, is passed through a layer of the pre-concentrated milk under controlled velocity conditions, creating a fluidized state. The milk particles are then dried by the hot air, and the resulting dried product can be further processed as needed.
Dehydration is a widely used method in the dairy industry to produce various dairy products, such as powdered milk, milk-based ingredients, and instant milk mixes. It offers advantages such as increased shelf life, reduced storage requirements, and enhanced convenience while preserving the nutritional value of milk.
5. Use of preservative agents
Preservatives are substances used to inhibit or retard the growth of microorganisms in food. In the case of milk and its products, various types of preservatives are employed to maintain their quality and extend their shelf life. These preservatives can be categorized into natural preservatives, bio preservatives, and chemical preservatives.
- Natural Preservatives:
- Milk: Honey and lecithin are natural preservatives that can be used to enhance the shelf life of milk.
- Cheese: Salt and essential oils, such as thyme, ginger, cayenne, clove, cinnamon, garlic, lemongrass, oregano, and basil, can act as natural preservatives in cheese.
- Butter: Salt, thymine, and cumin are natural preservatives that can help maintain the quality of butter.
- Bio Preservatives:
- Milk: LAB (lactic acid bacteria), bacteriocin, and hydrogen peroxide can be used as bio preservatives to inhibit the growth of microorganisms in milk.
- Cheese: Lysozyme, nisin, and LAB can act as bio preservatives in cheese.
- Chemical Preservatives:
- Milk: Chemical preservatives such as benzoic acid, sorbic acid, nisin, sodium diacetate, boric acid, and formaldehyde can be used to prevent microbial growth in milk.
- Cheese: Chemical preservatives like sorbic acid, potassium sorbate, propionic acid, and natamycin are commonly used in cheese to inhibit spoilage microorganisms.
- Ice Cream: Chemical preservatives including butyraldehyde, diethyl glycol, polysorbate 80, and potassium sorbate can be used to extend the shelf life of ice cream.
- Yogurt: Chemical preservatives like sodium benzoate, potassium sorbate, and natamycin are employed in yogurt to inhibit microbial growth and maintain product quality.
It is important to note that the use of preservatives should adhere to regulations and guidelines set by relevant food authorities to ensure the safety and quality of the final product. The type and concentration of preservatives used may vary depending on the specific product, intended shelf life, and regulatory requirements.
Guess the word hidden in this story
B. Low-temperature treatment
- Low-temperature treatment is a method of food preservation that involves storing foods at temperatures between 0 and 5 °C. This technique is commonly used for preserving milk and milk products, including cheese, yogurt, butter, and more.
- The main objective of low-temperature treatment, also known as chilling, is to slow down the rate of microbial growth and enzymatic activities in food. By reducing the temperature, the growth of spoilage-causing microorganisms is minimized, which extends the shelf life of milk and milk products. Chilling helps to maintain the quality and freshness of these products for a longer period.
- One of the advantages of low-temperature treatment is that it causes minimal changes to the nutritional properties of the food. Unlike other preservation methods that involve heat or chemical treatments, chilling does not significantly alter the nutrient composition or sensory characteristics of the products.
- Low-temperature treatment is often used in combination with other preservation methods to enhance the effectiveness of food preservation. For example, milk and milk products may undergo pasteurization, a heat treatment, before being stored in chilled storage. This combination of treatments helps to ensure the safety and quality of the products, as pasteurization eliminates or reduces pathogenic microorganisms, while chilling prevents the growth of spoilage-causing microorganisms.
- Chilled storage is widely employed in the dairy industry for the storage of milk, cheese, yogurt, butter, and other milk-based products. These products are carefully stored at low temperatures to maintain their freshness, flavor, and texture. It is essential to adhere to proper temperature control and storage practices to maximize the benefits of low-temperature treatment and ensure the safety and quality of the stored products.
C. Other Methods of Treating Milk
- Microfiltration is a method of milk processing that involves the use of a membrane filtration system to remove bacteria and other microorganisms from milk. It is a filtration technique that operates on a microscopic level, utilizing specialized membranes with small pore sizes to separate particles based on their size.
- The main objective of microfiltration is to reduce the microbial load in milk and extend its shelf life. By removing significant numbers of bacteria, yeasts, and molds, microfiltration helps to prevent spoilage and improve the safety of the milk. This process is particularly useful in preserving milk without affecting its nutritional properties, flavor, or other desirable characteristics.
- Microfiltration is often used in combination with other milk processing methods, such as high-temperature short-time (HTST) pasteurization. HTST pasteurization involves heating milk to a high temperature for a short period to kill pathogenic bacteria while retaining its quality. By combining microfiltration with HTST pasteurization, the overall microbial load in milk can be significantly reduced, further enhancing its safety and extending its shelf life.
- During microfiltration, milk is passed through a membrane system with tiny pores, typically ranging from 0.1 to 0.5 micrometers in size. These pores are small enough to trap and remove bacteria and other microorganisms, while allowing the desired components of milk, such as proteins, lactose, and vitamins, to pass through. The filtration process can be performed at relatively low temperatures, preserving the natural characteristics of the milk.
- Microfiltration is an effective method for reducing the microbial content in milk, but it is important to note that it may not completely eliminate all microorganisms. Therefore, proper storage and handling practices should still be followed to ensure the safety and quality of the milk.
- Overall, microfiltration is a valuable technique in milk processing, as it allows for the removal of bacteria and extends the shelf life of milk without the need for high-temperature treatments that may affect its taste and nutritional value. By combining microfiltration with other preservation methods, milk producers can provide consumers with safer and longer-lasting milk products.
- Bactofugation is a specialized centrifugation process used in the dairy industry to remove bacteria from milk. It is particularly effective in reducing the bacterial count, thus helping to minimize spoilage and improve the quality of milk and dairy products.
- The main objective of bactofugation is to separate bacteria from milk by subjecting it to high centrifugal forces. This process is especially beneficial in preventing the growth of specific bacteria that can lead to spoilage issues in dairy products, such as “late blowing” in cheese caused by certain clostridia species.
- During bactofugation, milk is subjected to high-speed centrifugal forces that cause the bacteria to separate from the milk. The centrifugal force drives the bacteria towards the outer edges of the centrifuge, allowing the bacteria-free milk to be collected separately. The separated bacteria are then discarded, while the bacteria-reduced milk can proceed for further processing.
- By removing a significant portion of bacteria, bactofugation helps to extend the shelf life of milk and dairy products. It reduces the risk of spoilage, off-flavors, and textural defects that can be caused by certain bacterial species. This process is particularly beneficial in cheese production, as it minimizes the presence of spoilage-causing clostridia bacteria responsible for late blowing, a defect that leads to gas formation and undesirable texture in cheese.
- It’s important to note that while bactofugation is effective in reducing bacterial counts, it does not eliminate all bacteria. Therefore, proper storage and handling practices are still necessary to ensure the safety and quality of dairy products.
- In summary, bactofugation is a centrifugation process used in the dairy industry to remove bacteria from milk. It plays a crucial role in minimizing spoilage issues, particularly in cheese production, by reducing the presence of specific bacteria that can lead to defects. By employing bactofugation alongside other milk processing and preservation techniques, dairy producers can enhance the quality and shelf life of their products.
3. Ohmic heating
- Ohmic heating is an innovative method of heating food products by passing an alternating electric current directly through the product. It is a form of direct heating where the food itself becomes part of an electric circuit.
- During ohmic heating, an alternating electric current is passed through the food product, which acts as a resistor to the electric current flow. This resistance generates heat within the product, resulting in rapid and uniform heating. The electric current flows between two electrodes, and the food product, being a conductor, allows the current to pass through it.
- The main objective of ohmic heating is to achieve precise and controlled heating of food products. This method offers several advantages over traditional heating methods. Firstly, it enables rapid and uniform heating throughout the product, eliminating temperature gradients and ensuring consistent quality. Ohmic heating also allows for precise control of temperature, reducing the risk of over or undercooking. Additionally, it can lead to reduced processing times and improved energy efficiency.
- Ohmic heating is suitable for a wide range of food products, including liquids, particulates, and even solid foods. It has been applied to various dairy products, such as milk, cream, and sauces, to achieve gentle and efficient heating while preserving the sensory and nutritional qualities of the product.
- One of the key advantages of ohmic heating is its ability to minimize processing time and maintain product quality. The rapid and uniform heating provided by ohmic heating helps in preserving the nutritional content, flavors, colors, and textures of the food. This makes it particularly beneficial for heat-sensitive products, where traditional heating methods may lead to quality deterioration.
- Furthermore, ohmic heating has been found to be effective in reducing microbial populations in food products, thereby improving their safety and extending their shelf life. The heat generated during ohmic heating can help in reducing pathogenic and spoilage microorganisms, providing an additional benefit for food preservation.
- In summary, ohmic heating is a direct heating method that utilizes an alternating electric current to heat food products. It offers advantages such as rapid and uniform heating, precise temperature control, and improved energy efficiency. Ohmic heating can help in preserving the sensory and nutritional qualities of food products while providing enhanced microbial safety. This technology has the potential to revolutionize the food processing industry by offering efficient and high-quality heating solutions.
4. Microwave heating
- Microwave heating is a food processing technique that utilizes electromagnetic waves to generate heat within the food. It involves the use of microwave energy at specific frequencies, commonly 2450 or 900 MHz, to induce molecular friction and heat the food product.
- In the food industry, microwave heating has found various applications, including milk pasteurization. The use of microwaves for milk pasteurization has been in commercial practice for a considerable period. Microwave pasteurization offers several advantages over traditional pasteurization methods.
- One of the primary benefits of microwave heating is its rapid and uniform heating capabilities. Microwaves penetrate the food product and directly interact with water molecules, causing them to vibrate and generate heat. This leads to efficient and even heating throughout the food, reducing the risk of undercooked or overheated areas.
- Microwave pasteurization also offers the advantage of reduced processing time. The rapid heating achieved through microwaves allows for shorter pasteurization cycles compared to conventional methods. This can lead to increased productivity and reduced energy consumption.
- Furthermore, microwave pasteurization can help preserve the sensory and nutritional qualities of the milk. The shorter heating time and lower overall thermal exposure minimize the potential for flavor and nutrient loss. This makes microwave-pasteurized milk a viable option for consumers seeking products with minimal processing impact.
- It is important to note that microwave pasteurization must be carefully controlled to ensure proper pathogen inactivation. The specific time and temperature parameters must be determined to achieve the desired level of pathogen reduction while maintaining product safety. Proper process validation and monitoring are essential to ensure the effectiveness of microwave pasteurization in eliminating harmful microorganisms.
- In summary, microwave heating is a food processing method that utilizes electromagnetic waves to generate heat within the food. It has been applied in various areas of the food industry, including milk pasteurization. Microwave pasteurization offers advantages such as rapid and uniform heating, reduced processing time, and potential preservation of sensory and nutritional qualities. However, it requires careful control and validation to ensure proper pathogen inactivation and product safety.
5. Pulse Electric Field
- Pulse Electric Field (PEF) is a non-thermal food preservation technology that utilizes short pulses of high electric fields to treat food products. In this process, the food is placed between two electrodes, and it is subjected to pulses with durations ranging from nanoseconds to milliseconds and intensities typically ranging from 10 to 80 kilovolts per centimeter (kV/cm).
- PEF treatment has been shown to have a lethal effect on vegetative bacteria, molds, and yeasts present in food. The high electric fields disrupt the cellular membranes of microorganisms, leading to their inactivation or death. PEF treatment can effectively reduce the microbial load in food, thereby extending its shelf life and improving its safety.
- The effectiveness of PEF treatment in microbial inactivation depends on various factors, including the specific electric field strength, pulse duration, number of pulses applied, and the characteristics of the food product being treated. Different microorganisms may have varying susceptibilities to PEF treatment, and the process parameters need to be optimized for each specific application.
- One of the advantages of PEF technology is its non-thermal nature. Unlike traditional thermal processing methods such as pasteurization, PEF treatment does not rely on high temperatures to achieve microbial inactivation. This non-thermal approach helps preserve the sensory and nutritional qualities of the food, as it minimizes the exposure to heat.
- In addition to microbial inactivation, PEF treatment has been reported to have other potential benefits. It can enhance the extraction of bioactive compounds from food matrices, improve mass transfer processes, and modify the structure and texture of certain food products.
- However, it is important to note that PEF technology is still being researched and developed for commercial food applications. Further studies are needed to optimize process parameters, assess the impact on food quality and safety, and establish guidelines and regulations for its implementation.
- In conclusion, Pulse Electric Field (PEF) is a non-thermal food preservation technology that uses short pulses of high electric fields to inactivate microorganisms in food. It has a lethal effect on vegetative bacteria, molds, and yeasts. PEF treatment offers the advantage of non-thermal processing, which helps preserve the sensory and nutritional qualities of the food. However, further research and development are required to optimize the technology and ensure its safe and effective implementation in the food industry.
6. High-pressure process (HPP)
- High-pressure processing (HPP) is a non-thermal pasteurization method used in the food industry to improve food safety and extend shelf life. In this process, food products are subjected to high levels of hydrostatic pressure, typically ranging from 3300 to 6000 megapascals (MPa), for a period of about 10 minutes.
- The application of high pressure inactivates microorganisms by disrupting their cellular structure and components. The high-pressure conditions lead to the denaturation and unfolding of proteins, disruption of cell membranes, and inactivation of enzymes. As a result, both pathogenic and spoilage-causing microorganisms can be effectively inactivated, including bacteria, yeasts, molds, and some viruses.
- HPP has several advantages as a food preservation method. It does not rely on heat, which means that the sensory and nutritional qualities of the food are better preserved compared to traditional thermal pasteurization methods. Additionally, HPP can extend the shelf life of food products by reducing the microbial load and inhibiting enzymatic activity that causes spoilage.
- HPP is particularly effective in inactivating vegetative microorganisms, while some bacterial spores and certain heat-resistant pathogens may survive the process. Therefore, it is important to consider the specific target microorganisms and their resistance to high pressure when applying HPP for food preservation.
- Various food products can be processed using HPP, including juices, sauces, meats, seafood, dairy products, and ready-to-eat meals. The process is conducted in specially designed equipment that can withstand the high pressures involved.
- It is important to note that HPP is not a sterilization method, as it may not completely eliminate all microorganisms and their spores. Therefore, proper handling, storage, and refrigeration conditions are still necessary to maintain the safety and quality of HPP-treated products.
- Overall, high-pressure processing (HPP) is a non-thermal pasteurization method that utilizes high hydrostatic pressure to inactivate microorganisms in food. It offers advantages in terms of food safety, extended shelf life, and preservation of sensory and nutritional attributes. However, each food product and target microorganism should be carefully considered to optimize the HPP process parameters and ensure the desired microbial inactivation.
- Ultrasound is a technology that utilizes high-power sound waves at frequencies between 16 kHz and 100 MHz for various applications, including food processing. In the context of milk and milk products, ultrasound can be used as a non-thermal treatment method for microbial control and preservation.
- During ultrasound treatment, high-frequency sound waves are passed through the milk, causing alternating compression and rarefaction cycles. This leads to the phenomenon known as cavitation, where the rapid changes in pressure create small gas bubbles in the liquid. These bubbles undergo expansion and collapse, generating localized high temperatures and pressures. The physical and chemical effects of cavitation, such as microstreaming, shockwaves, and free radicals, contribute to the bactericidal effect of ultrasound.
- Ultrasound treatment has been studied for its potential in inactivating microorganisms in milk and dairy products. It has shown efficacy against a wide range of bacteria, yeasts, molds, and viruses. The bactericidal effect of ultrasound is attributed to the disruption of cellular structures and the denaturation of proteins in microorganisms, leading to their inactivation.
- One application of ultrasound in milk processing is the treatment of Bacillus subtilis spores. In experiments, milk samples containing B. subtilis spores have been subjected to ultrasound treatment at temperatures ranging from 70 to 95 °C. The ultrasound waves effectively target the spores, leading to their inactivation and reducing the microbial load in the milk.
- Ultrasound treatment offers several advantages in food processing. It is a non-thermal method, which means that it can achieve microbial inactivation without significantly affecting the sensory and nutritional properties of the milk. It is a rapid and efficient process, allowing for high-throughput applications. Additionally, ultrasound is a green technology, as it does not require the use of chemical additives or high temperatures.
- However, it is important to note that the effectiveness of ultrasound treatment may vary depending on the specific microorganisms and process parameters used. Factors such as frequency, intensity, treatment time, and temperature need to be optimized for each application to achieve the desired microbial control.
- In conclusion, ultrasound is a technology that utilizes high-power sound waves for microbial control in milk and milk products. It can provide a non-thermal treatment option, effectively inactivating microorganisms through the process of cavitation. Further research and optimization of ultrasound parameters are needed to fully harness its potential in milk processing and ensure the safety and quality of dairy products.
8. UV Radiation and Irradiation
- UV Radiation and Irradiation are two methods used in food preservation to control microbial growth and ensure the safety of dairy products.
- Ultraviolet (UV) radiation is a form of electromagnetic radiation with a wavelength of about 10-400 nm. It is commonly used in the food industry as a non-thermal method for microbial control. UV radiation works by damaging the genetic material (DNA or RNA) of microorganisms, thereby inhibiting their ability to reproduce and causing their inactivation. It is primarily effective against surface microorganisms and is often used for disinfection purposes, such as in UV sterilizers for water or air treatment.
- On the other hand, irradiation involves the use of ionizing radiation sources such as gamma rays, X-rays, or accelerated electron beams. These sources emit high-energy radiation that can penetrate deeper into the food matrix and cause molecular changes, including the destruction of microorganisms. Irradiation can be used in dairy products to control pathogens or reduce the overall microbial load. It can effectively eliminate bacteria, molds, yeasts, and even some parasites in food.
- In cheese production, UV radiation can be used in combination with the pasteurization of brine. The brine used for cheese brining is exposed to UV radiation to control the growth of spoilage microorganisms and reduce the risk of contamination. This helps to ensure the safety and quality of the cheese during the aging process.
- Irradiation can be applied to dairy products to achieve different objectives. It can be used to destroy pathogens such as E. coli, Salmonella, Listeria, and other harmful bacteria. By subjecting dairy products to ionizing radiation, the DNA or RNA of microorganisms is damaged, leading to their inactivation. Irradiation can also extend the shelf life of dairy products by reducing spoilage microorganisms, molds, and yeasts.
- It is important to note that both UV radiation and irradiation have specific regulations and guidelines governing their use in food preservation. These regulations ensure that the treatments are applied within safe limits to avoid any negative effects on food quality or consumer health. Proper dosages, exposure times, and monitoring are necessary to ensure the effectiveness and safety of UV radiation and irradiation in preserving dairy products.
- In conclusion, UV radiation and irradiation are methods used in food preservation, including dairy products. UV radiation is effective against surface microorganisms, while irradiation can penetrate deeper into the food matrix to control pathogens and reduce microbial load. These techniques offer benefits in terms of microbial control and shelf life extension. However, adherence to regulations and guidelines is crucial to ensure their safe and effective application in dairy product preservation.
What is the purpose of preserving milk and milk products?
Preservation of milk and milk products aims to extend their shelf life by inhibiting the growth of microorganisms that can cause spoilage and deterioration.
Why is microbial spoilage a concern in milk and milk products?
Microbial spoilage can lead to changes in taste, odor, and texture of milk and milk products, rendering them unappetizing and unfit for consumption. It can also pose health risks if pathogenic microorganisms are present.
What are the common methods of preserving milk and milk products?
Common methods of preservation include pasteurization, sterilization, dehydration, chilling, the use of preservative agents, and non-thermal techniques such as high-pressure processing and pulsed electric fields.
How does pasteurization help in preserving milk?
Pasteurization involves heating milk to a specific temperature for a certain period to kill or inactivate harmful microorganisms while retaining the nutritional quality of the milk. It extends the shelf life of milk and improves its safety.
What is the purpose of sterilization in milk preservation?
Sterilization involves subjecting milk to high pressure or temperature to destroy all microorganisms, including both spoilage-causing organisms and pathogens. It allows milk to be stored at room temperature without refrigeration.
How does dehydration contribute to milk preservation?
Dehydration involves removing water from milk, reducing the water activity that microorganisms need for growth. It helps in extending the shelf life of milk by inhibiting microbial growth and preventing spoilage.
What role do preservative agents play in milk preservation?
Preservative agents, such as natural, bio, and chemical preservatives, are used to inhibit or retard the growth of microorganisms in milk and milk products. They help prevent spoilage and maintain product quality.
How does chilling contribute to milk preservation?
Chilling milk and milk products at temperatures between 0-5 °C slows down the growth of microorganisms, thereby extending their shelf life. It is a common method used in dairy storage and transportation.
What are non-thermal techniques used in milk preservation?
Non-thermal techniques, such as high-pressure processing, pulsed electric fields, ultrasound, UV radiation, and irradiation, are used to inactivate microorganisms without relying on heat. These methods help preserve the quality and safety of milk and milk products.
Are preserved milk and milk products safe for consumption?
Preserved milk and milk products are safe for consumption if preservation methods are applied correctly and within regulatory guidelines. It is important to follow proper handling, storage, and usage instructions provided for each preserved product to ensure safety.
- Jay, J. M. (2000). Sixth Edition./Modern Food Microbiology
- Kharel G.P., H. F. (2010Principle of Food Preservation,
- William C. Frazier; Fourth Edition.pdf (1995). Food Microbiology,
- Ameer, S., Aslam, S., & Saeed, M. (2019). Preservation of Milk and Dairy Products by Using Biopreservatives. 2(4), 72–79.
- Fernandes, R. (2009). MICROBIOLOGY HANDBOOK DAIRY PRODUCTS. Retrieved from http://www.leatherheadfood.com
- Húngaro, H. M., Peña, W. E. L., Silva, N. B. M., Carvalho, R. V., Alvarenga, V. O., & Sant’Ana, A. S. (2014). Food Microbiology. In Encyclopedia of Agriculture and Food Systems. https://doi.org/10.1016/B978-0-444-52512-3.00059-0
- Gershom, N., & Ssemakula, E. (2017). Traditional Methods of Milk Processing and Preservation by Local Farmers in Kashongi Sub County Kiruhura District. 2(2), 62–71. https://doi.org/10.11648/j.ajset.20170202.12
- Khorshidian, N., Yousefi, M., Khanniri, E., & Mortazavian, A. M. (2018). Potential application of essential oils as antimicrobial preservatives in cheese. Innovative Food Science and Emerging Technologies, 45(October), 62–72. https://doi.org/10.1016/j.ifset.2017.09.020
- Krushna, N. S. A., Kowsalya, A., Radha, S., & Narayanan, R. B. (2007). Honey as a natural preservative of milk. In Indian Journal of Experimental Biology (Vol. 45).
- M. Shafiur Rahman Boca. (2007). Handbook of Food Preservation Second Edition.
- Menderes, A., Ziraat, Ü., Dergisi, F., Kaptan, B., Keser, G., Termal, S. U., & İşlemler, O. (2018). Derleme / Review Non-Thermal Processes Used in Milk Treatment. 15(2), 101–106. https://doi.org/10.25308/aduziraat.412337
- Nahm, H., Juliani, H., & Simon, J. (2012). Effects of selected synthetic and natural antioxidants on the oxidative stability of shea butter (Vitellaria paradoxa subsp. paradoxa). JournalofMedicinally1(2),5–10.Retrievedfrom http://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1003&context=jmap
- Upadhyay, N., Goyal, A., Kumar, A., Ghai, D. L., & Singh, R. (2014). Preservation of Milk and Milk Products for Analytical Purposes. Food Reviews International, 30(3), 203–224. https://doi.org/10.1080/87559129.2014.913292
- Watts, S. (2016). A mini review on technique of milk pasteurization. ~ 99 ~ Journal of Pharmacognosy and Phytochemistry, 5(5). https://doi.org/10.1136/bmj.1.4286.261
- Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Effects of the vat pasteurization process and refrigerated storage on the bovine milk metabolome. Journal of Dairy Science, 103(3), 2077–2088. https://doi.org/10.3168/jds.2019-17512