Several studies can answer this question:
• MEDSurg Nursing - 2020(1)
[...] ENFit design [...]
The way Enfit is designed poses a problem for cleaning the distal end of the tube. In fact, there is a hollow where residue from the enteral preparation or drugs are likely to accumulate and encourage proliferation of bacteria.
(1) Lyman, B., Rahe, K. L., Keeler, D., Sherman, A. K., & Abdelhadi, R. A. (2020). Randomized Controlled Trial Assessing the Effectiveness of Two Cleaning Regimens for ENFit Connectors. Medsurg Nursing, 29(6), 401-406.
• MEDSurg Nursing - 2020(2)
Comparing 2 cleaning protocols, protocol A / the more rigorous cleaning protocol and protocol B / the less rigorous cleaning protocol, the investigators found only 35 (31%) and 13 (16%) of the ENFit connectors, respectively, to be free of residue after cleaning.
(2) Lyman, B., Rahe, K. L., Keeler, D., Sherman, A. K., & Abdelhadi, R. A. (2020). Randomized Controlled Trial Assessing the Effectiveness of Two Cleaning Regimens for ENFit Connectors. Medsurg Nursing, 29(6), 401-406.