PHP: strip the tags off the value inside array_values()

I want to strip the tags off the value inside array_values() before imploding with tabs.

I tried with this line below but I have an error,

$output = implode("\t",strip_tags(array_keys($item)));

ideally I want to strip off the line breaks, double spaces, tabs from the value,

$output = implode("\t",preg_replace(array("/\t/", "/\s{2,}/", "/\n/"), array("", " ", " "), strip_tags(array_keys($item))));

but I think my method is not correct!

this is the entire function,

function process_data($items){

    # set the variable
    $output = null;

    # check if the data is an items and is not empty
    if (is_array($items)  && !empty($items))
    {
        # start the row at 0
        $row = 0;

        # loop the items
        foreach($items as $item)
        {
            if (is_array($item) && !empty($item))
            {
                if ($row == 0)
                {
                    # write the column headers
                    $output = implode("\t",array_keys($item));
                    $output .= "\n";
                }

                # create a line of values for this row...
                $output .= implode("\t",array_values($item));
                $output .= "\n";

                # increment the row so we don't create headers all over again
                $row++;
            }
        }       
    }

    # return the result
    return $output;
}

Please let me know if you have any ideas how to fix this. Thanks!