Provisional tests carried out by Public Health England have confirmed that the group who attended the Buckatree Hall Hotel near Wellington on August 7 were struck down by the sickness bug norovirus, which was unlikely to have been spread by hotel staff.
This means that the illness that causes sickness had been spread by someone carrying the viral infection.
PHE said it was "unlikely that this is a member of staff at the hotel" due to no other reports among other guests who ate the same food falling ill.
Ann Fleming, Public Health England regional spokesperson, said: "We have just received confirmation that the samples from our laboratories have tested positive for norovirus.
"No other organisms has been detected so far.
"All the food samples have tested negative.
"There are no reports of illness in guests outside of the wedding party."
Norovirus, often associated with hospitals, is one of the most contagious causes of gastrointestinal illness.
PHE said further tests were due to be completed and that the hotel was due to be contacted with the provisional results.
There were no reports of sickness from any other party eating at the venue on the same day and it has had no further reports on subsequent days.
Around 30 people, including the bride and groom, later complained of sickness and cramps at the ceremony at Buckatree Hall Hotel.
Public Health England West Midlands then launched an investigation to find out what caused reports of “gastroenteritis” among guests.
It said around 30 had complained of symptoms and that its experts were working with environmental health colleagues at Telford & Wrekin Council following reports of a stomach bug affecting a number of people within 48 hours of visiting the hotel near The Wrekin.
A wedding guest, who did not want to be named, said most of the 56 people in the wedding party had been poorly and that 10 had been to hospital.
The hotel has been contacted by the Shropshire Star.