Access cell data from selected row

I could use a little insight on .rows('.selected').data(). I need to access cell data from a selected row but I can not even get past to accessing the TR data. My following scripts returns [object Object] in my alert, when I should see the data in the selected rows. I exhausted all my resources trying to solve this. Any help would be greatly appreciated .

var mfgTable;
$(document).ready( function () {
    mfgTable = $( "#ManufacturerTable" ).DataTable({
                           ordering:  false,
                           iDisplayLength: 20,
                               oLanguage: {sSearch: "Table Search: "},
                                    processing: true,
                                    serverSide: true,
                                    ajax: {url: "ssp_getManufacturersData.php",}
                           },
                                 columns: [
                                             { orderable: false,
                                               className: 'select-checkbox',
                                               targets:   0,
                                               data: null,
                                               defaultContent: '',
                                               width: '10px',
                                             },
                                             { data: "vendor_number"},
                                             { data: "manufacturer_name" },
                                             { data: "manufacturer_address"},
                                             { data: "manufacturer_city" },
                                             { data: "manufacturer_state" },
                                             { data: "manufacturer_zipcode" },
                                             { data: "manufacturer_type" },
                                             { data: "manufacturer_status" },
                                 ],
                              
                                 select: {
                                    style:    'os',
                                    selector: 'td:first-child'
                                 },
    });
} );
// Function called from button after row is checked
function getTableRowData( ){

      var tableData = mfgTable.rows('.selected').data();
      var tempData;
    
          $.each(tableData , function(i, val) {
       
                tempData= tableData [i];
            alert(tempData);

      });