Cold King agents are here to discuss how the transportation time, temperature, and vehicle hygiene directly affect the quality and shelf life of fresh meat. Using refrigerated trucks as carriers, monitor the changes in temperature, relative humidity, and wind speed over transportation time.

The detoxification effect of different dosages of sodium hypochlorite on train carriages was studied, with a constant temperature of 4 ℃ as the control. Cold fresh meat was transported under temperature conditions of 1 ℃ increase, 2 ℃ increase, 1 ℃ fluctuation, and 2 ℃ fluctuation. The influence of temperature changes on its quality was studied, and the transportation conditions of cold fresh meat were optimized through orthogonal experiments.

The results showed that the RH distribution inside the refrigerated truck was uniform, the cooling below the refrigeration unit was fast, the temperature fluctuation was small, the wind speed was high, followed by the sides of the carriage, and the disinfection effect of 300mg/kg sodium hypochlorite was better.

Under the condition of temperature fluctuation of 1 ℃, there was no significant difference in the pH value, total volatile basic nitrogen content, juice loss rate, and total bacterial count of the meat sample compared with the control group (P>0.05). Two optimized transportation conditions were developed, namely, using 300mg/kg sodium hypochlorite to disinfect the carriage, transporting for 6 hours, and ensuring the quality of cold fresh meat under constant 4 ℃ or temperature fluctuation of 1 ℃ conditions.

In the process of transporting goods in refrigerated trucks, the thickness and material selection of the insulation layer directly affect the insulation effect of the compartment. For different thicknesses, materials, vehicle speeds, insulation temperatures, external temperatures, etc., physical models can be established to analyze the influence of various parameters on the insulation effect through theoretical calculations and simulations, providing some basis for the selection of various parameters for refrigerated trucks.

Due to the fact that the thickness of the carriage wall is much smaller than its length and width, it can be simplified as a large flat wall heat transfer situation. Only the one-dimensional heat transfer along the thickness direction of the carriage wall is analyzed. After simplification, it is found that the thickness of the insulation layer, the difference between the refrigeration temperature and the air temperature have a significant impact on the heat leakage rate of the carriage. As the vehicle speed increases, the heat leakage rate of the carriage increases, but not significantly.