I would imagine if there is considerable vote fraud that can be proven, then the state of Mississippi would conduct it.
Of course, it would have to go to court, and somehow be settled before the general election...
If you have a county that votes 90% Democratic, and it suddenly has 500 votes in this election, then that might raise the flag that there is significant FRAUD in that county.
Thus, certain counties might be suspsect such as those that vote very heavily Democratic and do not vote Republican.
An example would be the county Jackson, MS, is in (which I believe is Jackson County, but not sure).
The votes of that county could be canvassed for those who voted in the Democratic Primary.
Then just that county could be 'audited' (somehow) and re-counted -- only counting the valid votes...
Jackson MS is in Hinds county.
Watch Hinds for fraud.
Also Hattiesburg.