The RAL-GZ 992/3 RAL Quality Certification Mark for Linen from Food Processing Businesses is a separate RAL Mark which includes both process control under RAL-GZ 992/1 and a hygiene certificate. Prerequisites include membership of the German Certification Association for Professional Textile Services and evidence of process control. This is monitored on site at the company by HOHENSTEIN, using technical hygiene and microbiological tests. The RAL-GZ 992/3 RAL Hygiene Certificate for Linen from Food Processing Businesses is also awarded by the German Certification Association for Professional Textile Services for one year.