With the purpose of accomplishing this goal, the food samples which were collected from some markets in Hanoi were processed, followed by extraction and purification of viral RNA, then the RT-LAMP reaction was tested to select optimal conditions (concentration of reverse transcriptase enzyme: 2U / reaction; annealing temperature: 63 °C; concentration of betaine for GI: 1M, for GII: 0.8M; incubation time: 60 minutes) with detective sensitivity 10 copies / reaction and specificity of 100% for tested strains.