Enteral nutrition may appear as a risk factor for infection in intensive care patients if bacterial growth is not prevented. The authors have tested in the microbiology laboratory, 4 types of pumps (3 cooling machines: SEC Nutridose/Climadose, Peters NPR 3000, Vial "Alaska" and 1 flow regulator Sherwood Kangaroo 330) using food contaminated with a low inoculum of Klebsiella pneumoniae. Bacterial growth was investigated periodically in the food container and in the feeding tube during the testing of the pumps. Results showed that external refrigeration is the best cooling method. But after 8 hours of working, the best results were obtained with the flow regulator associated with a container cooled by an ice pocket. These in vitro results can be extended in vivo by taking care of changing the sterile tubings for each new dose of food.