Comparison of PET bottle hot filling and aseptic cold filling technology

Comparison of PET bottle hot filling and aseptic cold filling technology

After more than ten years of unremitting efforts, pet aseptic cold filling technology has become more and more perfect, and more and more beverage varieties are produced, including fruit and vegetable juice drinks, tea drinks, sports drinks, carbonated drinks, water, etc. At present, PET bottled milk drinks are very common in North America and Europe. In the process of bottle blowing, by adding a proper barrier layer, the permeability of the bottle can be solved, which makes the application of PET bottle in beer field more realistic.

Key points of pet aseptic cold filling technology

◆ the product is sterile after UHT.

How to get the ideal shelf life of the initial product after blending is realized by high temperature sterilization. UHT ultra-high temperature sterilization process is generally used in pet aseptic cold filling production line to achieve this goal. At present, there is no clear definition of ultra-high temperature sterilization in the world. Generally speaking, the sterilization method with temperature between 138-145 ℃ and time between 1-30 seconds is high temperature short-time sterilization, which is commonly used in most aseptic packaged foods.

When designing UHT ultra-high temperature sterilization process for pet aseptic filling production line, proper sterilization temperature and time should be selected to improve the sterilization value (FO value) of the product as much as possible, and at the same time to ensure that the flavor and nutrients of the product can be retained to the maximum extent. At present, most of pet aseptic cold filling production lines use tube type ultra-high temperature sterilizer.

◆ sterilization of packaging materials is the most critical step in aseptic cold filling production process

Because the standard PET bottle is not heat-resistant, only chemical reagents can be used for sterilization. To ensure that the bottle and cover are effectively sterilized and the chemical reagents cannot affect the product, the following measures are taken for aseptic filling:

1. It is required that the original colony number of the initially blown bottle shall not exceed 10 CFU / bottle.

2. Sterile air is used for conveying bottle, equipped with air conveyor belt.

3. Peracetic acid disinfectant is used inside the bottle for sterilization, which can achieve high sterilization effect.

4. Sterilize the outside of the bottle with disinfectant at the same time

5. The disinfectant has an automatic recovery and concentration measurement system to ensure the disinfectant concentration is stable.

6. Rinse the residual disinfectant in the bottle with sterile water, and then dry it with sterile air to ensure that the residual disinfectant will not affect the material.

7. The cap is generally sterilized by soaking with disinfectant, and the sterilization effect is ensured by controlling the soaking time.

◆ aseptic filling equipment

The main equipment requirements of aseptic cold filling are in line with food hygiene design, mainly in pipe and valve technology, material surface polishing, surface design of important areas, selection of corrosion resistant materials and other advantages. It also has CIP system, SIP system and equipment external foam cleaning system (COP). In addition, aseptic cold filling machines are designed with their own unique aseptic filling valves. These measures ensure that the equipment will not bring secondary pollution to the materials.

Because PET bottle will not shrink after cold filling, there will be a part of air between the material and the bottle cap, and the oxygen in it will slowly oxidize the material during the storage process, resulting in the deterioration of the beverage. Therefore, the aseptic cold filling equipment will add a set of nitrogen (or other inert gas) replacement system to blow the top air away to ensure that the product is not oxidized as much as possible.

◆ filling and capping in sterile environment

In order to maintain the aseptic environment of pet aseptic cold filling line, the isolation measures of air purification room are generally adopted. At present, the use of purification room in food processing enterprises is developed from the pharmaceutical industry, and the technical level has a unified standard.

The main filling machine area of pet aseptic cold filling is required to be designed as D100 level aseptic room, and there is a 10000 level purification room outside. The aseptic air filtration system in the purification room ensures the air cleanliness in the filling environment, so that the materials will not be secondary polluted by the suspended microorganisms in the air. At the same time, the temperature and humidity of the purification room are controlled to ensure that the aseptic filling machine is always in good working condition.

In the whole environmental system, the operator is the biggest pollution source. The air purification room is designed to purify the air and reduce the pollution brought by the personnel. When the operator enters the 10000 level purification room, he needs to spray for sterilization. The 100 level purification room is designed to be small and practical, so that the operator can operate without damaging the sterile environment. The inner surface of the purification equipment can For automatic cleaning and disinfection.

◆ establishment, monitoring, recording and control of key control points of aseptic cold filling production line

The production of pet aseptic cold filling line is a very responsible continuous production process. In this process, any operation error or secondary pollution of product microorganism may cause the failure of the whole aseptic control system and affect the safety of the whole batch of products. Therefore, the establishment of scientific and perfect monitoring and control system is the key factor for the successful operation of aseptic cold filling production line. At present, HACCP management system is widely used in the beverage industry.

HACCP is the abbreviation of hazard analysis and critical points. It is a highly logical and evaluation system management method that can enable food production enterprises to identify and control potential hazards in a timely manner in the production environment, so as to prevent unqualified products. The system consists of seven basic principles, including the determination of critical control points (CCPs) for hazard control, the establishment of critical limits (CL) for each control point, and the establishment of procedures for monitoring each control point.

The process of pet aseptic cold filling production line is complex, and the control requirements of aseptic environment are very strict. Only in accordance with the HACCP system to manage and control, can we truly ensure product safety.

Hot filling process

The hot filling process can be generally divided into two types: one is hot filling at high temperature, that is, after UHT instantaneous sterilization, the material is cooled to 85-92 ℃ for filling, at the same time, the product reflux is required to maintain a constant filling temperature, and then maintain the temperature for sterilization of the bottle cap; the other is pasteurization at 65-75 ℃ after material sterilization and filling and adding preservatives. These two methods do not need to sterilize the product, bottle and lid separately, only need to keep the product at high temperature for a long time to achieve the sterilization effect.

Comparison of two filling technologies

The biggest difference between the two filling processes is that the heating time of the beverage is different. As we all know, the longer the heat treatment time, the greater the impact on the quality of beverages. Sterile cold filling only uses UHT ultra-high temperature instantaneous sterilization, the material heating time is short, the loss of nutrients is little, the quality and taste have no obvious change, and in the high temperature situation, it can completely guarantee the sterilization effect; while the sterilization method of hot filling makes the material in the high temperature state for a long time, which seriously affects the taste, color and the content of thermosensitive nutrients of the product.

The hot filling technology determines that the hot filling method is only suitable for the production of high acid products. Because the high acid environment itself has the inhibition effect on microorganisms, it can not guarantee the safety of low acid drinks, and the product defect rate is high. If neutral tea beverage is produced by hot filling process, preservative should be added. For aseptic cold filling, because the whole process is carried out under aseptic conditions, its process adaptability is very strong, and it can produce products

It has a wide range of types, including neutral tea drinks, milk drinks and various other drinks. The product type can be changed by adjusting the pretreatment equipment properly.

Hot filling technology aseptic cold filling technology

Quality requirements for bottle and bottle cap: crystalline heat-resistant PET bottle (able to withstand high temperature of 85 ℃ - 92 ℃ without deformation) and special heat-resistant bottle cap are required; ordinary PET bottle (maximum heat-resistant temperature of 60 ℃) and standard cap can be used.

Materials are required to be kept at high temperature for a long time and preservatives are added. Materials are cooled to normal temperature after UHT sterilization.

Sterilization requirements for bottles and non sterilization or ozone water, simple washing with chlorine water must be soaked in disinfectant or sprayed for sterilization

Sterilization requirements for bottle cap: UV irradiation or simple washing with chlorine water; it must be soaked in disinfectant or sprayed for sterilization

The requirements of filling environment are not as high as that of aseptic cold filling, which can be achieved by 100 thousand level purification in the filling area; there are almost no microorganisms in the filling room and the filling line in the early stage.

Filling equipment requirements: the filling system adopts the external circulation mode and CIP is required; the non-contact filling mode is required; the perfect CIP and sip systems are required; the filling space requirements and the external packaging transfer mode are strictly required.

Requirements for later filling stage: bottle pouring sterilization chain and spray cooling equipment are required; no post-treatment is required.

Practical operation, simple operation of process environment, relatively loose quality control management, extremely complex operation of process environment and strict quality control management requirements

Operational risk is small and large

It has a certain influence on the flavor of the product and has little influence.

Comparison of two PET bottles

It can be seen from the filling process that the requirements of the two filling methods for PET bottles are different. The hot filling process requires that PET bottle can bear the high temperature of 85-92 ℃ without deformation, which requires increasing the crystallinity of PET material and limiting the generation of induced stress when blowing the bottle. The PET bottle used has the following characteristics: the bottle wall is thick, and needs high degree of crystallization to enhance the thermal stability; the high tensile rate has reached the hardness; there are clear ribs on the bottle wall to prevent thermal shrinkage; there is a requirement for crystal bottle mouth, which greatly limits the freedom of bottle design.

The aseptic cold filling can use the standard pet light bottle (the maximum heat-resistant temperature is 60 ℃) and the standard cover, which greatly reduces the cost of the bottle and the cover, and can freely design the unique bottle type according to the product characteristics, and carry out the personalized packaging.

Advantages of pet aseptic cold filling compared with hot filling

High quality

The short heating time, the manufacturing and maintenance of sterile environment and scientific management methods ensure the high quality of sterile cold filling products.

Low cost

The low cost advantages of aseptic cold filling products can be shown in a short time due to the saving of raw materials, energy consumption and personnel.

◆ wide applicability

With the development of aseptic filling technology, the filling process of various beverages and drinks is getting closer and closer, and the applicability is getting higher and higher.

Project hot filled PET bottle aseptic cold filled PET bottle

Bottle heavy light

Bottleneck special crystallization bottleneck standard bottleneck

Raw material ratio high requirement standard

Bottle type design special bottle type with hot ribs user-friendly bottle type design

Withstand temperature: 85-92 ℃; 60 ℃

Oxygen permeability, bottle wall thickness, low oxygen permeability, thin bottle wall, high oxygen permeability

Cap? High temperature resistant cap? Standard cap

Bottle and lid cost high low