Reference check of the previous employment should be limited to:
a) Authenticity of the information provided by the candidate in his/her CV
b) Employee should not have been removed because actions involving moral turpitude (whether in personal or professional life)
c) He/she should have not have been terminated because of theft or destructive activities of any kind
If the negative feedback is received then you must approach the company and ask whether they had conducted any domestic enquiry and misconduct was proved. Mere blaming the employee without following principles of natural justice is unprofessional.
Occasionally, senior management professionals or HODs bear grudge against the junior employee and when he/she quits, to teach him/her lesson, they give negative feedback. This feedback needs to be ignored.
Negative feedback on account of poor performance has to be ignored. While selecting a job candidate, you should have been cautious enough to test candidate's knowledge or skills. If the candidate clears recruitment rounds, but if you withhold his/her candidature because you receive poor feedback on performance then it shows that you do not have trust on your recruitment ability.
Hope the above information is sufficient.
1st March 2018 From India, Bangalore