There were no positive results from Koln's second round of coronavirus testing, the Bundesliga club announced on Monday.
Koln revealed on Friday three unspecified individuals at the club had contracted Covid-19 and were told to undergo a 14-day quarantine procedure, however further testing carried out on Sunday found no further cases of coronavirus.
A statement from the club read: "On Sunday, 1. FC Koln had the entire team, as well as the coaching and backroom staff, tested for Covid-19. All tests from the independent laboratory were negative.
"On Monday morning, Markus Gisdol's team will continue to train in groups. Training is not open to the public.
"The medical concept from the DFL [German Football League] sees the regular testing as a prerequisite for the possible continuation of the league. Only players who have been tested negatively twice in succession are allowed to train and play."
The trio who tested positive – which reportedly consists of two players and a physio – were consequently told to undergo a 14-day quarantine procedure.
Koln midfielder Birger Verstraete criticised the decision to continue training in the aftermath of the positive tests, though he later backtracked on his comments.
After Koln responded and dismissed Verstraete's comments, the 26-year-old said: "I gave an interview about my personal concerns about my girlfriend potentially getting the virus. I expressed myself falsely in a few places, so that in the translation a misunderstanding has came about and I am sorry for that."
He previously said in an interview with Belgian TV station VTM: “We aren't quarantined for the time being, and that's a bit bizarre.
“At the moment football is not the most important place for me, especially because it is getting so close now. I had previously seen images of intensive care, and now it appears that the virus is also close to us. So it's bit strange that everything just keeps going.”
The Bundesliga has been suspended since March 13 due to the coronavirus pandemic but a decision on its potential resumption will be made on Wednesday.
Koln have stated they are ready to move into a "quarantine-like" training camp if the green light is given to finish the 2019-20 season behind closed doors.