Contribution of the main contaminating materials during pig slaughter to the microbial numbers on carcasses 
J. Tholen, M. Upmann, Letters in Applied Microbiology 77 (2024).

Type, areal extent and localization of carcass contaminations during industrial pig slaughter
J. Tholen, J. Grosse-Kleimann, G. Schulze Althoff, L. Kreienbrock, M. Upmann, Meat Science 208 (2023).