Research progress of the hottest food antibacteria

Research progress of food antibacterial packaging film

food antibacterial packaging film is a new research hotspot in food packaging today. With the progress of society and the improvement of people's living standards, consumers' demand for convenient, fast and fresh food is increasing. Food safety and food quality have become the most concerned issues

now, in order to solve the problem of food decay and deterioration under the action of physical, biochemical, harmful microorganisms and other factors, and even produce toxic substances, which seriously affect the health of consumers, antibacterial packaging materials made of adding a certain amount of antibacterial agents into food packaging materials can be divided into antibacterial films, antibacterial hollow containers, antibacterial bags and antibacterial turnover boxes, Among them, food antibacterial packaging film is the most widely used

requirements for packaging film substrate

there are many methods to prepare food antibacterial packaging film. One is to make the antibacterial agent into antibacterial masterbatch, which is prepared by extruding or salivating the antibacterial agent or antibacterial masterbatch and resin monolayer. It can also be extruded together as a surface layer and other layers to form an antibacterial composite film. Another is obtained by coating or evaporating antibacterial agent on resin film

for the antibacterial film prepared from the antibacterial masterbatch, due to the thin thickness of the film itself, the particle size of the antibacterial particles is required to be small, and the distribution of the particle size is relatively narrow or the organic antibacterial agent that can be dissolved in the resin is used. Generally, the addition of antibacterial agent or antibacterial masterbatch has no obvious effect on the mechanical properties of the film, and the insulation aging has no adverse effect on the printing properties of the film. However, it has a certain impact on the barrier performance of some films, so when selecting antibacterial agents and antibacterial masterbatches, we should pay attention to the impact of the addition of antibacterial agents and antibacterial masterbatches on the performance of the film, and select appropriate antibacterial agents to ensure that the performance of the packaging meets the use requirements. Generally, the packaging materials used include LDPE, LLDPE, EVA, cellulose film, edible film, etc

for the method of coating or evaporating antibacterial agent on the film, the barrier performance of different plastics varies greatly. If the substrate is not damaged during the coating and coating process, it can still affect the quality of the final product. The surface properties, performance polarity, surface roughness, the percentage of oxygen and nitrogen atoms on the surface of plastic film will affect the bonding strength between the film and antibacterial agent, thus affecting the antibacterial properties. In addition, before the antibacterial agent is coated or evaporated on the film, the surface of the film substrate should be pretreated in advance to improve its surface properties and adhesion. The packaging film substrates used for coating or evaporation generally include pet, PA, PVC, BOPP, LDPE, etc

in addition to meeting the mechanical properties, printing properties, display properties and other necessary properties of packaging materials required by commodity packaging itself, all countries in the world have high requirements for the hygienic properties of packaging materials used for food products. China's national standard gb-9687 stipulates the hygienic requirements for food packaging materials, requiring the materials to have normal color, no odor, no odor, no foreign matter, and meet the corresponding requirements in terms of evaporation residue, potassium permanganate consumption, heavy metal content, decolorization test, etc. FDA has also made specific provisions on the composition of food packaging materials, additive specifications, use conditions, dissolution requirements, chronic toxicity test requirements of food packaging materials, sub chronic toxicity test requirements, etc

different types of food antibacterial packaging films

1 Inorganic antibacterial agent film

inorganic antibacterial agent is an antibacterial agent prepared by using the bactericidal and antibacterial ability of silver, copper, zinc, titanium and other metals and their ions. In the early 1980s, Japanese scientists began to add silver compounds directly to the resin, and made antibacterial plastic films with inorganic antibacterial agents for the first time

antibacterial mechanism: because the inorganic antibacterial agent is a dissolution contact antibacterial agent, the antibacterial effect of the inorganic antibacterial agent film is passive. At present, there are two explanations for the antibacterial mechanism of metal ions

one is contact reaction mechanism. The metal ions in the inorganic antibacterial agent film contact with microorganisms, causing the destruction of microbial protein structure, causing microbial death or dysfunction

one is the mechanism of reactive oxygen species. The micro metal ions distributed on the surface of the inorganic antibacterial agent film can absorb the energy in the environment, activate the oxygen adsorbed on the surface of the packaging film in air and water, and produce hydroxyl radicals and reactive oxygen ions. They have strong redox ability, can destroy the reproductive ability of bacterial cells, inhibit or kill bacteria, and produce antibacterial effect

application of inorganic antibacterial film. At present, there are few inorganic antibacterial agents used in food packaging films. It is reported that apaciaer antibacterial agent developed and produced by sangegroup in the United States is a kind of silver loaded hydroxyapatite, which is widely used in food packaging. In addition, because silver has good sterilization ability, silver oxide or silver is plated on PET film through vacuum coating, which is used as food packaging material

2. Organic antibacterial agent film

antibacterial mechanism: the main action mechanism of organic antibacterial agents is to gradually enter cells by combining with anions on the surface of microbial cell membranes, or react with sulfhydryl groups on the surface of cells, destroy the synthesis system of proteins and cell membranes, and inhibit the reproduction of microorganisms. Application of organic antibacterial film. At present, TBZ (2-benzimidazole) produced by Mike company of the United States, OBPA produced by akcros chemical company and ir-guard produced by Ciba company have all passed the FDA certification. Organic antibacterial agents used in food packaging can be added to resins to make thin neoprene films for food antibacterial packaging. Science and technology once said that it would enter the field of high molecular materials with the help of this acquisition

3. Photocatalytic inorganic antibacterial agent film

antibacterial mechanism: the current photocatalytic antibacterial agent is mainly TiO2, which can produce a large number of hydroxyl radicals and oxygen radicals on the surface under the action of light. These two radicals have strong chemical activity and can make various microorganisms decompose organically, so they have antibacterial properties

application of photocatalytic inorganic antibacterial agent film. Since photocatalysts were first marketed in Japan in 1995, food packaging has become a widely used field

4. Natural and polymer antibacterial agent films

other antibacterial agent films include natural antibacterial agent films and polymer antibacterial agent films. Their antibacterial mechanism is through the charge on the molecular chain and the requirement of micro displacement accuracy is very low biological effect, so as to inhibit microbial reproduction and play an antibacterial role. At present, chitosan, sorbic acid and gingerol are mainly used in food packaging

5. Composite antibacterial agent film

the effect of composite antibacterial agent film is mainly reflected in the following aspects: extending the antibacterial cycle; Low concentration can produce antibacterial properties; Broaden the antibacterial spectrum and inhibit more microorganisms than any single antibacterial film

at present, the compound antibacterial agents used in food packaging have not been reported, but in the Japanese market, there are few models of this kind of experimental machine below 10kN. The compound antibacterial agent triazine antibacterial agent, which is composed of organic antibacterial agents triazine mildew inhibitor and pyridine antibacterial agent, has increased its antibacterial effect by 3-4 times. The compound antibacterial agent of organic antibacterial agent and inorganic antibacterial agent developed by the National Engineering Research Center of helco chemical engineering plastics overcomes the problem of single function of kfhs series antibacterial agent. In addition, nano TiO2 can be added to inorganic silver antibacterial agents in food packaging films to solve the problem of slow antibacterial effect of silver antibacterial agents

all kinds of antibacterial films have their advantages and disadvantages. Their characteristics are summarized in the attached table

prospect of food antibacterial packaging film

food antibacterial packaging is the most promising part of food active packaging. After sterilization and aseptic packaging or vacuum packaging of some foods, it is difficult to achieve the original aseptic effect when the packaging of foods is damaged during transportation or stored after opening. In this case, choosing antibacterial film packaging is the most beneficial. It can continuously release antibacterial agents to inhibit the growth of microorganisms, ensure the safety of food, and extend the shelf life of food

food antibacterial packaging film is in the early stage of development, and there are still some problems worthy of attention:

1 Safety of food antibacterial packaging film. Before application, it should be tested to see whether its antibacterial agent will be transferred to food. At present, some new technologies have emerged, such as UV excited atom laser radiation treatment of packaging film materials, modification of base resin molecular chains, antibacterial agent functional groups, etc. These technologies may solve the safety problem of antibacterial packaging film, and have a very wide application prospect

2. Multifunctional of food antibacterial packaging film. Develop some packaging that can not only resist bacteria, but also improve the color, aroma and taste of food, or some indicative packaging. Solving these problems will open up a broader field for food packaging materials

source: China Packaging News