Abstract: This paper briefly introduces the application advantages and antibacterial principle of antibacterial packaging, explains the importance of detection of antibacterial packaging, and introduces the detection methods of various gaseous antibacterial agents on packaging materials, and proves through test data. The importance of this type of testing.
Keywords: barrier properties, antibacterial packaging, gaseous, antibacterial agents, organic gases
The requirements for antibacterial and antiseptic foods are much higher than those for pharmaceuticals, household chemicals, and electronic products. This is because foods are made from a mixture of various components that are easily deteriorated. The commonly used antibacterial and antiseptic method is to add preservatives, but the safety of this method has been controversial. The introduction of antibacterial packaging has greatly eased the dependence on food preservatives, and has become effective in improving the quality of food preservation and reducing the amount of additives. means.
1. Application limitations of preservatives
Traditional food antibacterial and antiseptic methods use preservatives in them, but there are several significant problems with this method. First, the impact of the addition of preservatives on food safety. Although some preservatives have been used for many years, they have gradually exposed safety hazards with the deepening of research. For example, the widely used preservative benzoic acid has been reported to have accumulated poisoning in recent years. Second, consumer acceptance of preservatives. Although preservatives are widely used, preservative-free foods are still the first choice for consumers. Third, since the preservative is added to the food, it takes a period of time (the length of time is related to the amount of preservative added) to be released to the surface of the food and to exert antibacterial and antiseptic effects. Therefore, even if preservatives are added to the food, the environment is preserved. There are still higher requirements.
2. Antibacterial packaging
The antibacterial principle of antibacterial packaging is different from that of preservatives. The antibacterial property is achieved by adding an antibacterial agent inside or on the surface of the packaging material. Basically, the antibacterial ingredients are not transferred to the inside of the food, so that the food is safer. Therefore, the introduction of the antibacterial packaging is Reducing the amount of preservatives provides a means to use them alone or in combination with food preservatives.
Antibacterial packaging is not required to kill harmful microorganisms quickly, but rather to inhibit their growth and reproduction during long-term use to protect food. To achieve this goal, it is necessary to slowly "release" the antimicrobial agent at the most appropriate rate through a controlled release technique in the design of the antimicrobial packaging system to match the growth kinetics of the target microorganism. The antibacterial agent is the core of the antibacterial packaging system, and for any kind of microorganism, the antibacterial agent has its own specific antibacterial activity, and the antibacterial agent should be selected according to the activity on the target microorganism. Antibacterial chemicals suitable for food packaging include organic acid salts, sulfurous acid, nitrous acid, antibiotics and ethanol, etc., which are mainly classified into solid type, solute type and gaseous type. Compared with solid-state and solute-type chemical antibacterial agents, gaseous antibacterial agents have obvious advantages. They can evaporate and penetrate into the space where the non-gaseous antibacterial agent in the package can not reach, the sterilization range is more comprehensive, and the antibacterial agent is located in the head space. It does not directly contact with food, so that the antibacterial agent does not easily diffuse into the food, thereby ensuring the safety and hygiene of the food.
The nature of the antimicrobial packaging material directly affects the environment within the package and can have an impact on the antimicrobial effect. The hydrophilicity of the antibacterial agent is often better than that of the film material, and the antibacterial agent fills the pores inside the material, so the addition of the antibacterial agent usually has mechanical properties such as tensile strength, burst strength and toughness of the material and gas permeation. Subtle changes in properties such as water vapor permeability, moisture absorption, oil resistance and gloss. Some antibacterial agents play a very important role in the properties of packaging materials. For example, the use of antioxidants to create an oxygen-free atmosphere in the package to limit the spoilage caused by mold growth places high demands on the barrier properties of packaging materials. . In addition to the oxygen barrier and water resistance of the packaging material, the gaseous antibacterial agent needs to consider the permeability of the gaseous antibacterial agent itself to the packaging material. For example, the ethanol bag needs to consider the ethanol gas in the headspace to the packaging. The permeability of the material requires an ethanol permeability test of the packaging material to avoid failure of the antimicrobial packaging system due to the escape of the ethanol gas from the package.
3. Barrier testing requirements for antimicrobial packaging
The influence of the antibacterial agent on the material is related to the amount and type of the antibacterial agent. Therefore, the antibacterial packaging material should be tested and comprehensively tested to avoid loss of strength of the material. However, for antibacterial packaging using a gaseous antibacterial agent, special attention needs to be paid to the detection of the permeability of the antibacterial gas to the packaging material.
Gases such as chlorine dioxide and ozone that are flammable, explosive or toxic at high concentrations can be detected by the differential pressure method in the conventional gas permeability test method, but custom equipment is required and targeted. Structural adjustments were made to determine the nature of the gas. Labthink has provided custom-made services for differential pressure equipment for special gas permeability tests. Organic vapors such as ethanol, because such gases can swell the sample film, and thus the barrier properties change significantly. Therefore, the detection method of organic gas transmittance is very different from that of inorganic gases. Research in the field is still in the development stage. Labthink's newly developed PERME TM OR2/410 organic gas transmission rate test system uses an equalization method to detect the organic gas permeability of the sample. The instrument has a patented structural design, mainly consisting of a permeation chamber, an organic gas generating device, and a timing sampling valve. The separation chamber and the FID flame ionization detector are simple in operation and are the most automated organic gas permeability detection devices.
Figure 1 PERME TM OR2/410 Organic Gas Transmission Rate Test System
At present, Languang Laboratories has completed the detection of the permeability of several common soft packaging films by organic substances such as ethanol, acetone and toluene. Some data can be seen in Table 1.
Table 1. Ethanol Permeability of Common Materials
Material type | Ethanol transmission rate ( g/m 2 .24h ) |
PC ( 125um ) | 0.21 |
AL ( 100um ) | 0 |
PET ( 19um ) | 0.02 |
PE ( 40um ) | 7.17 |
Comparing the ethanol permeability of the above materials with the oxygen transmission rate and the water vapor transmission rate, it is not difficult to see that the transmittance of the organic gas does not have the same or close to the oxygen transmission rate and the water vapor transmission rate. . Although the barrier properties of the material itself are still the determinants of organic gas permeability, the type of organic matter and the properties of the material will have an impact on the final data. Therefore, the error caused by the conventional gas permeability or water vapor transmission rate of the material to infer the organic gas permeation characteristics of the material will become an important factor in the failure of the antimicrobial packaging system.
4. Summary
With increasing packaging requirements and concerns about food safety, antimicrobial packaging has become more and more used in a variety of foods. However, antibacterial packaging is not a simple combination of antibacterial and packaging. The two functions interact and restrict each other. To find the most appropriate balance between the two must rely on material testing. With the advancement of detection technology, more and more inspection projects have completed the leap from qualitative detection to quantitative detection. The development of these detection technologies will eventually promote the development and progress of antibacterial packaging.
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