In contrast, high-temperature short-time treatment (HTST, e.g., 62 • C/5 s) preserves bioactive HM proteins compared to Holder pasteurization while effectively inactivating CMV (10).
| Temperature | Time | Pasteurization Type |
|---|---|---|
| 63ºC (145ºF)* | 30 minutes | Vat Pasteurization |
| 72ºC (161ºF)* | 15 seconds | High temperature short time Pasteurization (HTST) |
| 89ºC (191ºF) | 1.0 second | Higher-Heat Shorter Time (HHST) |
| 90ºC (194ºF) | 0.5 seconds | Higher-Heat Shorter Time (HHST) |
What is high-temperature short-time pasteurization (HTST)?
The most common method of pasteurization in the United States today is High Temperature Short Time (HTST) pasteurization, which uses metal plates and hot water to raise milk temperatures to at least 161° F for not less than 15 seconds, followed by rapid cooling. Higher Heat Shorter Time (HHST) is a process similar to HTST pasteurization, but ...
Can a booster pump be installed in a conventional HTST pasteurization system?
Jul 08, 2016 · Temperature: HTST pasteurization: HTST pasteurization has a much lower temperature. (71.7 °C) UHT pasteurization: UHT pasteurization has a comparatively higher temperature. (140°C) Duration: HTST pasteurization: HTST pasteurization takes much longer duration with compared to UHT pasteurization. UHT pasteurization: UHT pasteurization takes …
How do HTST pasteurizers ensure safety?
Apr 05, 2019 · HTST Pasteurization. In high-temperature short-time (HTST) pasteurization, also known as Flash pasteurization, the product is heated to the minimum temperature and held continuously at or above that temperature for at least the minimum time required. This thermal treatment extends the shelf life of product by eliminating vegetative and ...
What are the steps of UHT pasteurization?
Temperature Time Pasteurization Type; 63ºC (145ºF) 1) 30 minutes: Vat Pasteurization: 72ºC (161ºF) 1) 15 seconds: High temperature short time Pasteurization (HTST) 89ºC (191ºF) 1.0 second: Higher-Heat Shorter Time (HHST) 90ºC (194ºF) 0.5 seconds: Higher-Heat Shorter Time (HHST) 94ºC (201ºF) 0.1 seconds: Higher-Heat Shorter Time (HHST) 96ºC (204ºF) 0.05 seconds
What is the temperature of HTST pasteurization?
What is the difference between Ltlt and HTST pasteurization?
What is the difference between HTST pasteurization and UHT pasteurization?
How does pasteurization differ from ultrahigh temperature treatment?
What is Ltlt and HTST?
What is the advantage of high temperature short time pasteurization HTST compared with sterilization?
What is pasteurization What are the methods used give the meaning of UHT & HTST?
What temperature is UHT milk heated to?
How does high temperature short time pasteurization HTST work?
What is the difference between homogenised and Unhomogenised milk?
What are the 3 types of pasteurization?
- High Temperature Short Time. In the United States, the most common method of pasteurization is High Temperature Short Time (HTST). ...
- Higher Heat Shorter Time. ...
- Ultra High Temperature. ...
- Ultra Pasteurized.
What is HTST method?
What is pasteurization in medical terms?
Pasteurization is defined as partial sterilization of a substance and especially a liquid (as milk) at a temperature and for a period of exposure that destroys objectionable organisms without major chemical alteration of the substance. It was invented by Louis Pasteur. In HTST Pasteurization, the product is subjected to much lower temperature (71.7°C, almost half of the temperature which is used for UHT method) over a long period (15 seconds) compared to UHT Pasteurization. This is the key difference between HTST and UHT pasteurization techniques and further differences are described in this article.
How is milk pasteurized?
Basic Steps of HTST Pasteurization of Milk 1 Cold raw milk is fed into the pasteurization plant 2 The milk passes into the regenerative heating section of the plate heat exchanger. 3 In the regenerating section, cold milk is pumped through the A chambers (odd numbered chambers in series of chambers) while milk that has already been heated and pasteurized is pump through the B chambers (even numbered chambers). 4 The heat from hot milk passes into the cold milk through steel plates. This warms the milk to 57 – 68 °C (134.6-154.4 °F) 5 Next, milk passes to the heating section of the plate heat exchanger. Hot water in B chamber heats the milk to around 72 °C (71.7°C). 6 Then it passes through the holding tube and takes 15 seconds to complete the passage by fulfilling the time requirement of HTST pasteurization. 7 After that, it is re-sent to the regenerative section where milk is again cool to 32 °C. 8 Then the cooling section of the plate heat exchanger uses coolant or cold water to bring the temperature of pasteurized milk to 4 °C.
How long can milk be stored in a UHT machine?
The milk is packaged in sterile hermetically-sealed containers. Therefore, it can be stored for up to 90 days without refrigerating conditions.
How is cold milk pumped?
Cold raw milk is fed into the pasteurization plant. The milk passes into the regenerative heating section of the plate heat exchanger. In the regenerating section, cold milk is pumped through the A chambers (odd numbered chambers in series of chambers) while milk that has already been heated and pasteurized is pump through the B chambers ...
What is HTST in dairy?
HTST is the most common pasteurization technique in the dairy industry. HTST stands for High Temperature, Short Time. It is also known as flash pasteurization. It is a method of pasteurizing perishable beverages like fruit and vegetable juices, beer, kosher and wine. Pasteurization makes the product safe for consumption and extends the shelf life compared to unpasteurized products. It removes spoilage microorganisms. This was first introduced in 1993 and observed 99.99% reduction of harmful bacteria. This is a faster and energy efficient method, and it maintains the color and flavor of most products.
How long does it take for a HTST to pass through a holding tube?
Then it passes through the holding tube and takes 15 seconds to complete the passage by fulfilling the time requirement of HTST pasteurization.
When was UHT milk first used?
UHT milk was first used in 1960.
What is HTST pasteurization?
In high-temperature short-time (HTST) pasteurization, also known as Flash pasteurization, the product is heated to the minimum temperature and held continuously at or above that temperature for at least the minimum time required. This thermal treatment extends the shelf life of product by eliminating vegetative and pathogenic microorganisms.
Why is pasteurization important?
Products that can be completely pasteurized are beer, canned food, milk and milk product, eggs, juices, low alcoholic beverages, syrups, vinegar, water, wines, nuts, etc. It is important to handle the pasteurized product in refrigerated condition after pasteurization to prevent the recontamination of product.
How does a HTST process work?
Stepwise flow of process in HTST starts with product entering the balance tank and is drawn under reduced pressure to the regenerator section. In the regenerator section, the product is pre-warmed by hot product flowing through regenerator plates. The product is then drawn through the timing pump to the heating section. The now-hot product flows through the holding tube. The product contacts the indicating thermometer and the recording thermometer. If it has not reached the minimum required temperature, it is returned back to the constant level tank via the diversion port. If the product is at or above the minimum required temperature, it passes through the regenerator plates (on the pasteurized side) and then to the cooling section. The product exits the cooling section and rises to an elevation of at least 12 inches above any raw product. Finally, the product passes to a storage tank for packaging.
What is a regenerator section?
Regenerator: The regenerator section pre-warms cold raw milk by the heat given up by hot pasteurized milk flowing in a counter-current direction and separates pasteurized and raw product with stainless steel plates.
Why is it important to keep pasteurized products refrigerated?
It is important to handle the pasteurized product in refrigerated condition after pasteurization to prevent the recontamination of product . Temperature and time for process is set on the basis of product and targeted microorganism of the product. Effectiveness of pasteurized product can be detected by various means.
Where is the timing pump located in a HTST?
Timing Pump: The timing pump controls the flow rate within the HTST system. It is located after the raw regenerator and before the holding tube. It draws raw milk through the raw regenerator and pushes it forward. The pasteurized product is always under greater pressure than the raw.
Is a tubular heat exchanger a PHE?
Tubular heat exchanger (THE): Unlike PHEs, THEs have no contact points in the product channel. THEs may have either a double-tube or triple-tube design. However, from the standpoint of heat transfer, the THE is less efficient than the PHE. The tubes within a THE have spiral or corrugated surfaces to increase turbulence and heat exchange.
What is the lethality of pasteurization?
During pasteurization, the food is heated to a defined temperature, and held at that temperature for a defined time period. The lethality associated with the pasteurization process is based on the holding period only; impact of elevated temperatures on lethality during heating and cooling are not significant or are not considered. The pasteurization of milk (shown previously in Fig. 2.1) is based on reduction of a microbial pathogen with D63 =2.5 min and z =4.1°C; and a thermal death time of 12 D, or 30 min. This process ensures that the probability of survival of the pathogen is negligible.
Why is pasteurization important?
Pasteurisation is crucial to many processes, for example cheese-making, ice-cream manufacture and powdered milk production, to ensure that these are free of pathogenic microorganisms. Again, in all these processes, it is crucial to reduce ppc, to ensure the best quality products. View chapter Purchase book. Read full chapter.
What is the lethal rate of HTST?
When the lethal rate for the HTST process is based on the reference temperature of 63°C, the magnitude is 120. The holding time needed to achieve the same lethality as the batch process is 15 s.
How to eliminate Yersinia enterocolitica?
Elimination by processing. Yersinia enterocolitica is not unusually heat resistant and will be eliminated by adequate thermal processing, including high-temperature short-time pasteurisation of milk and generally applied processes for cooking of meat.
How does dehydration affect the MFGM?
Dehydration, especially roller-drying, causes extensive damage to the MFGM, resulting in the formation of free fat. Since milk for concentrated and dehydrated milk products is normally homogenized, damage to the natural membrane is of little significance. Freezing milk, and especially cream, causes extensive damage to the MFGM due to physicochemical changes to the lipoprotein complexes and physical damage by the ice crystals. On thawing, much of the fat is released as nonglobular (free) fat.
What temperature is thermal process?
A thermal process is accomplished by instantaneous heating to 138°C followed by a 4-s hold and instantaneous cooling. Estimate the lethality at 121°C when the thermal resistance ( z) for the microorganism is 8.5°C.
Does pasteurization cause aggregation?
However, excessively high pasteurization temperatures denature the cryoglobulins, and aggregation of the fat globules and creaming are impaired or prevented.
What is a CLT in pasteurization?
The constant level tank (CLT) is a reservoir for a supply, at atmospheric pressure, of raw or recirculated product to the pasteurizer to permit continuous operation of the HTST pasteurization system. It is located at the start of the pasteurization system. It controls the milk level and provides a uniform head pressure to the product leaving the tank.
What are the factors that affect pasteurization?
Temperature and time are critical factors required to achieve pasteurization. Failure to achieve pasteurization could result in a microbiological hazard in the dairy products. The following are the generally accepted pasteurization schedules for dairy products produced by HTST pasteurization.
What is a raw product booster pump?
The booster pump is used to supplement the flow control device in moving raw milk from the constant level tank through the regeneration section. It may be used to remove excessive vacuum, and subsequent "flashing" or vaporization, in the regenerator section (particularly when the constant level tank is located an unusual distance from the timing pump).
Where is the booster pump located in a HTST?
When a booster pump is incorporated into the HTST system, locate it between the constant level tank and the inlet to the raw product side of the regenerator.
When to use culinary quality steam?
Use culinary quality steam if it comes in contact with product.
Can liquids cross contaminate pasteurization plates?
Since the physical distance between the various liquids in the pasteurization plates is extremely small, the liquids have the potential to move through the plates and cross-contaminate the product if pin holes exist.
Can air be drawn into pasteurizer?
Ensure the design and capacity of the tank does not permit air to be drawn into the pasteurizer with the product when operating at the maximum sealed capacity of the flow control device.
What is HTST in food?
HTST has now come to the forefront of the biopharmaceutical industry as a viral risk mitigation strategy to prevent costly contamination events. This technology has been optimized to ensure that the potential for product impact is minimized by reducing the residence time within the high temperature phase of the process. This maintains product quality while providing high viral inactivation.
What is HTST capability?
Our HTST capability has been developed to achieve robust viral clearance performance on high risk raw materials. The technology does not impact feed viability or performance. Utilizing pasteurized reactorfeed products can significantly reduce the probability of viral contamination events and contributes to a high level of virus safety assurance.
What is post treatment performance analysis?
Post-treatment performance analysis has been performed to ensure that the safeguarding effect of pasteurization does not come at the cost of cell culture performance. Figure 3 shows the results of cell growth and viability assessments.
What is HTST pasteurization?
High temperature short time pasteurization is a continuous process that efficiently and effectively destroys microorganisms in milk products. An HTST pasteurization system is a modular unit that includes a plate-and-frame heat exchanger, stainless steel balance tank, pumps, holding tube, valves piping and controls. Vat pasteurization, or the holding method, is the oldest method for pasteurizing food products. However, over the years HTST has gained favor in the food industry for multiple reasons:
Why is HTST used in food?
However, over the years HTST has gained favor in the food industry for multiple reasons: Large equipment capacity allows large volumes at one time. Continuous process allows for bottling to begin when pasteurization begins. Highly energy efficient. Minimal chance of damage to milk product.
What is HTST in milk?
HTST, or high temperature short time pasteurization, has become one of the most common methods of pasteurization today. It is more frequently known as flash pasteurization, or the “continuous method”. Pasteurization destroys pathogenic organisms such as bacteria, viruses, protozoa, molds and yeasts in milk products to reduce bacterial content ...
Is HTST pasteurization more expensive than holding method?
Since HTST pasteurization requires more components, it can be more expensive than the holding method .
What is pasteurization of milk?
The pasteurization of milk is a special type of heat treatment, which can be defined as “any heat treatment of milk that secures the certain destruction of tubercle bacillus (T.B.) without markedly affecting the physical and chemical properties of the milk”.
How long does it take for milk to pasteurize?
Thermization should be applied only in exceptional cases. The objective should be to pasteurize all the incoming milk within 24 hours of arrival at the dairy.
Why was milk used for heat treatment?
By the end of the 19th century, heat treatment of milk had become so commonplace that most dairies used the process for some purpose or another, such as for milk intended for cheese and butter production. Before heat treatment was introduced, milk was a source of infection, as it is a perfect growth medium for microorganisms.
What is aseptic filling?
Aseptic filling, to avoid reinfection of the product, is an integral part of the process. Two alternative methods of UHT treatment are used: Indirect heating and cooling in heat exchangers, Direct heating by steam injection or infusion of milk into steam and cooling by expansion under vacuum.
Why is a higher flow velocity needed in a tubular heat exchanger?
Compared to a plate heat exchanger, a higher flow velocity is needed to create efficient heat transfer in a tubular heat exchanger.
When do you clean a heat exchanger?
A heat exchanger in a dairy must be cleaned at the end of a production cycle. This is done by circulating detergents the same way as the milk. The cleaning process is described separately in Chapter 21.
Who invented the heat exchanger?
In 1878 a German, Albert Dracke, was granted a patent on an apparatus in which one liquid could cool another by each flowing in a layer on opposite sides of series of plates. It is not known whether any such patents, one of which covers the heat exchanger shown in Figure 6.1.15, ever left the drawing board. However, at the beginning of the 1920s, the old German ideas were reappraised, and a regenerative heat exchanger, based on these concepts, was launched. Since then, plate heat exchangers have assumed a predominant role for heating and cooling purposes in the dairy industry.