Fresh-cooked food such as red shrimp, braised beef and green beans, with rice, is cooled at room temperature and put into a box. The on-site staff introduced that the most advanced food preservation method in China-"modified atmosphere technology" was adopted. With the film covered by the packaging machine, the air pressure of the air conditioner will extract oxygen and carbon dioxide from the air of the box lunch, and at the same time fill in nitrogen to ensure that the food will not go bad. Then use air conditioner and air compressor to seal the film, and carry out the safety detection of metal detector. Wang Haibo, assistant general manager of Qingdao high-speed rail catering company, told reporters that the quality of box lunch can reach at least 72 hours.
The box lunch after "film sealing" is labeled by hand, and then enters the stage of "quick cooling". The on-site staff told the reporter that the box lunch with correct production date, shelf life and box lunch name will enter two "quick cooling tunnels", and the whole temperature will be MINUS 25-35 degrees Celsius, and the food will be quickly cooled to 0-5 degrees Celsius. After cooling, the box lunch is put into the fast food turnover box and sent to the cold storage in batches for quality inspection. Wang Haibo said that the center has two cold storage rooms for finished products to ensure that fast food is always stored at 0- 10 degrees Celsius. The quality inspection consists of three layers: first, the "quality control room" carries out the inspection by itself, and then sampling in batches. In addition, the quality inspection department also conducts random sampling inspection, including microbial detection, Escherichia coli, Salmonella, etc. 16.
After passing the sampling inspection, the box lunch will be transported to the fresh-keeping refrigerator of the high-speed train by two refrigerated transport vehicles, and the turnover box with ice rows and sealing strips will be used to ensure that the fast food is always stored at 0- 10 degrees Celsius.
From entering the cabinet to getting on the bus, the dining car service personnel should check the label of the box lunch before selling it to passengers: production date, shelf life and box lunch name. In the dining car, the reheating of box lunch should be strictly controlled in 3-4 minutes, and the reheating times should not exceed 1 time. The shelf life of box lunch is 72 hours, and the box lunch that has been heated, unsold, cracked and leaked and found abnormal will be broken and destroyed.