호기성 세균수와 CBS-X를 활용한 3단계 차량 소독 절차의 현장 평가 = Field evaluation of three-step livestock vehicle disinfection using CBS-X tracer and aerobic counts

다국어 초록 (Multilingual Abstract)

Livestock vehicles can mechanically transmit pathogens between farms. However, the effectiveness of multi-step disinfection in routine operations remains unclear. This study evaluated a three-step protocol using aerobic bacterial counts and compared the results with CBS-X tracer for on-site verification of disinfection effectiveness. The protocol consisted of passage through an enclosed vehicle disinfection facility, 15-min holding, and high-pressure spraying. A 2.5-ton livestock truck was assessed at 25 predefined sites across eight parts. At baseline and after each step, 5×5 cm area was swabbed by quadrants, cultured on Petrifilm Aerobic Count Plates (3M, USA), and log10 reduction was calculated.
The experiment was performed in triplicate. After the full three-step procedure, reductions differed by part, with higher reductions on the front (3.06 log) and steps (2.52 log) and lower reductions on the handles (0.92 log) and mudguards (0.53 log). The vehicle disinfection facility alone produced limited reductions (0.25∼1.81 log). During holding and after high-pressure spraying, some sites showed negative reductions, particularly on the handles and undercarriage. For tracer assessment, 1% CBS-X persistence was inspected under UV at baseline and after each step. After the disinfection facility, fluorescence was not detected on the front, side, and undercarriage, whereas it persisted on side steps and wheels but disappeared after high-pressure spraying. Handles were positive in 16.6% after both steps, and all mudguard sites remained positive. CBS-X was strongly associated with aerobic bacterial reduction (OR=26.464, P<0.001), indicating that UV inspection with CBS-X can rapidly detect inadequate disinfection and missed areas on site.