Dumoulin cited the MPCC's stance on ketones and Paris-Nice as his reason for leaving.
“I really like the MPCC's philosophy," the 2017 Giro champion said. "They pursue a cleaner sport and do not think the current doping rules are strict enough, especially in the field of cortisone use.
“Team Sunweb was a member of the MPCC and I was personally a member as well.
"But I thought it was a farce around Paris-Nice. In my opinion, that course should not have been taken. Then there was already the corona outbreak, also in France. There were really serious problems. Then the MPCC said nothing about that.
"Their motivation is that they are there for public health, but riding from Paris-Nice - which was the number one health risk at the time - was totally fine."
“And then they came up with the story that the use of ketones is very dangerous. (Jumbo-Visma) uses ketones, so it's a bit hypocritical for me to be a member of the MPCC. Those two things together moved me to unsubscribe. ”
The MPCC released a statement on March 18, four days after the final stage of Paris-Nice, about its support of 'very strict' health measures to stop the spread of the coronavirus.
"Because it is a matter of protection for everyone," the statement reads "because the health of the riders has always been our main focus and because we have been committed to fostering credibility for 12 years, MPCC asks everyone, and especially its members, to comply at once with all of the health measures with the same determination that it has shown towards sports and ethical rules."
In a 12 month period from March 2015, UAE, Astana, Jumbo-Visma (then LottoNL-Jumbo) Katusha (now defunct) and Mitchelton-Scott left the MPCC.
Jumbo-Visma left in June 2015, expressing concerns over the accuracy of the MPCC's cortisol tests which prevented Kiwi George Bennett from starting the Giro after he returned a low cortisol level. The MPCC's tests are designed to mitigate the abuse of corticosteroids as a low reading is said to indicate their use.
Just nine men's WorldTour teams remain members of the MPCC: Ag2R, Bora-hansgrohe, Cofidis, EF Pro Cycling, Groupama FDJ, Israel Start Up Nation, NTT Pro Cycling, Lotto Soudal and Team Sunweb.