Hygiene procedures of trucks transporting live pigs: multi-assessment validation of a standardized C&D protocol

Inadequately cleaned transport vehicles can act as reservoirs for pathogens jeopardizing pigs' health status. Although effective cleaning and disinfection (C&D) of live-pig transport trucks is required by law, there is still no universally accepted protocol for C&D of trucks. This study aimed to evaluate the effectiveness of a standardized hygiene protocol under field conditions and to provide practical guidance, thereby fostering harmonized hygiene procedures. Starting from current legislation for barn C&D, and refining it through available literature, a detailed standardized protocol for truck hygiene was developed. Each vehicle was divided into three functional sections: transport unit, boot-storage compartment, and driver's cabin. The protocol was applied to 15 trial trucks transporting live pigs and compared with 23 market trucks, which served as controls. C&D was assessed through visual inspection, adenosine triphosphate (ATP) testing, and microbiological analyses of environmental samples, including total viable count (TVC) on all trucks. Samples were collected at the three functional sections of the trucks. Trial trucks achieved significantly higher visual scores than control trucks (82.10 ± 9.72 vs. 72.20 ± 7.48; p = 0.0018). The 80% cleanliness threshold required for ATP testing was achieved by nearly half of the trial trucks (46.7%) but by only one control truck (4.3%) (p = 0.0065). Microbiological results further highlighted the protocol effectiveness: all cleaned trial trucks showed low mean TVC values (<10 CFU/cm² or a 3 log₁₀ CFU/cm² reduction, as acceptable threshold). In contrast, only 33.3% of driver's cabin swabs and 50.0% of cargo-area swabs from control trucks met this threshold, while none of the boot storage samples did (p = 0.0254). Bacteriological testing revealed MRSA in 100% of trial trucks before C&D, but in 0% after cleaning (p = 0.0079). Overall, the standardized protocol markedly improved the sanitary status of pig-transport vehicles. The combined use of different assessment methods proved valuable for identifying critical control points, particularly the boot-storage area, the most contaminated site. The protocol also showed strong potential for eliminating MRSA from trucks, contributing to reduce antimicrobial resistance transmission. These findings provide a replicable and field-ready model for improving C&D compliance and biosecurity across the swine transport sector.