With the development of economy and the improvement of people's living standards, more and more pets have entered more families, which is in line with the rapid development of the pet food industry. Like the general food industry, the pet food industry also has corresponding requirements for product safety and quality. Like other foods, pet foods have a certain shelf life.

According to AAFCO standards, pet food nutrients mainly include protein (more than 18%) and fat, and auxiliary nutrients include amino acids, minerals, crude fiber, crude ash and vitamins. These nutrients can not only meet the needs of pet growth, but also keep pet hair bright, but also a good natural medium for microbial growth.

As we all know, the reproduction of microorganisms requires a certain environment, in which the three important factors are ambient temperature, oxygen and moisture. Oxygen is the main external cause of rancidity. The less oxygen, the less likely the rancidity. Water can provide an active environment for microorganisms, accelerate the hydrolysis of fat, and shorten the shelf life of food. During the shelf life, the oxygen and moisture content in the packaging depends more on the integrity and barrier properties of the pet food packaging. The barrier properties of pet food packaging materials are particularly critical to the shelf life of pet food.

The impact of the barrier properties of pet food packaging materials on the shelf life of pet food:

During the shelf life, the oxygen and moisture in the complete pet food package mainly comes from the oxygen and water vapor permeating through the package. Barrier refers to the barrier effect of the packaging material on the penetration of gas or liquid molecules through the material. Seven kinds of pet food packaging materials, pet, pet CPP, BOPP/CPP, BOPET/PE, OPP/PE/CPP, BOPET/VMPET/LDPE and aluminum-plastic composite films, were selected to test, analyze and compare the oxygen transmittance and water vapor transmittance, respectively. The greater the oxygen transmission rate, the worse the oxygen resistance of the material; the greater the water vapor transmission rate, the worse the moisture resistance of the material.

Oxygen permeability test:

The measurement adopts the quasi-oxygen transmission test system and the principle of isobaric test. During the test, the sample is equilibrated in a standard environment (23±2°C and 50% relative humidity) for 48h, the wrinkle-free part is selected, and the circular sample is cut. The pretreated sample was placed in the middle of the upper and lower chambers of the ox2/230 oxygen permeability test system. At this point, the sample separates the upper and lower chambers. High purity oxygen flows in the upper chamber and high purity nitrogen flows in the lower chamber. During the test, oxygen molecules enter the lower chamber through the sample and enter the oxygen sensor through the flowing high-purity nitrogen gas. The oxygen concentration is detected by the oxygen sensor, and then the parameters such as the oxygen transmission rate of the sample are calculated. Test conditions of 23°C and 50% relative humidity were used for this test.

Moisture permeability test:

In addition to oxygen, water penetration in the air will also accelerate the deterioration process of pet food. This measurement uses the quasi-water vapor transmission rate test system. This test instrument belongs to the weighing method. As with the oxygen resistance test, select a balanced plate sample, put the sample into a moisture-permeable cup equipped with the instrument, and after secondary distillation, put an appropriate amount of distilled water into the moisture-permeable cup. At this time, a humidity difference is formed on both sides of the sample. During the test, the humidity difference on both sides of the sample was controlled by controlling the humidity in the test chamber. The water vapor transmission of the sample was calculated from the weight lost by the permeable cup during the test. The test uses measurement conditions of 38°C and 90% relative humidity.