As we are getting many quality answers, here is the most optimized code. Fastest, I bet :)
It wont work if you are using one of the ancient versions of excel. anything 2007+ is fine.
Sub OptimizedFOO()
    Dim rngTemp
    With Application.FindFormat.Interior
        .Color = vbRed
    End With
    '/ Sheet1 is example sheet name
    Set rngTemp = Sheet1.Columns(2).Find(What:="", SearchFormat:=True)
    If Not rngTemp Is Nothing Then
          MsgBox ("There is an issue with column B, please review.")
    End If
End Sub
Old answer 
Sub FOO()
    Dim answer As Range
    Dim cell   As Range
    '/ This will show message if at least one cell is found with red color
    Set answer = Range("b:b")
    For Each cell In answer.Cells
        If answer.Interior.Color = vbRed Then
            MsgBox ("There is an issue with column B, please review.")
            Exit For
        End If
    Next
End Sub