Remove BOM () from imported .csv file

I want to delete the BOM from my imported file, but it just doesn't seem to work.

I tried to preg_replace('/[\x00-\x1F\x80-\xFF]/', '', $file); and a str_replace.

I hope anybody sees what I'm doing wrong.

$filepath = get_bloginfo('template_directory')."/testing.csv";
            setlocale(LC_ALL, 'nl_NL');
            ini_set('auto_detect_line_endings',TRUE);
            $file = fopen($filepath, "r") or die("Error opening file");
            $i = 0;
            while(($line = fgetcsv($file, 1000, ";")) !== FALSE) {
                if($i == 0) {
                    $c = 0;
                    foreach($line as $col) {
                        $cols[$c] = utf8_encode($col);
                        $c++;
                    }
                } else if($i > 0) {
                    $c = 0;
                    foreach($line as $col) {
                        $data[$i][$cols[$c]] = utf8_encode($col);
                        $c++;
                    }
                }
                $i++;
            }

-----------
SOLVED VERSION:

setlocale(LC_ALL, 'nl_NL');
ini_set('auto_detect_line_endings',TRUE);
require_once(ABSPATH.'wp-admin/includes/file.php' );

$path = get_home_path();        
$filepath = $path .'wp-content/themes/pon/testing.csv';
$content = file_get_contents($filepath); 
file_put_contents($filepath, str_replace("\xEF\xBB\xBF",'', $content));

// FILE_PUT_CONTENTS AUTOMATICCALY CLOSES THE FILE
$file = fopen($filepath, "r") or die("Error opening file"); 

$i = 0;
while(($line = fgetcsv($file, 1000, ";")) !== FALSE) {
    if($i == 0) {
        $c = 0;
        foreach($line as $col) {
            $cols[$c] = $col;
            $c++;
        }
    } else if($i > 0) {
        $c = 0;
        foreach($line as $col) {
            $data[$i][$cols[$c]] = $col;
            $c++;
        }
    }
    $i++;
}

I found that it removes the BOM and adjusts the file by overwriting it with the new data. The problem is that the rest of my script doesn't work anymore and I can't see why. It is a new .csv file

Try this:

function removeBomUtf8($s){
  if(substr($s,0,3)==chr(hexdec('EF')).chr(hexdec('BB')).chr(hexdec('BF'))){
       return substr($s,3);
   }else{
       return $s;
   }
}

Correct way is to skip BOM if present in file (https://www.php.net/manual/en/function.fgetcsv.php#122696):

ini_set('auto_detect_line_endings',TRUE);
$file = fopen($filepath, "r") or die("Error opening file");
if (fgets($file, 4) !== "\xef\xbb\xbf") //Skip BOM if present
        rewind($file); //Or rewind pointer to start of file

$i = 0;
while(($line = fgetcsv($file, 1000, ";")) !== FALSE) {
    ...
}