DIN EN ISO 9233-1:2013-08

ISO 9233-1 specifies a method for the determination in cheese rind of natamycin mass fraction of above 0,5 mg/kg and surface-area-related natamycin mass of above 0,03 mg/dm2. It is possible that this method may be suitable for detecting migration of natamycin into the cheese interior. A known quantity of sample is extracted with methanol. The extract is diluted with water followed by cooling to between -15 °C and -20 °C to precipitate most of the fat, followed by filtration. The natamycin content or surface-area-related natamycin mass is determined in the filtrate (after concentration, if necessary) by molecular absorption spectrometry. The text of ISO 9233-1:2007 and Amendment 1:2012 has been prepared by Technical Committee ISO/TC 34 "Food products" (secretariat: AFNOR, France), Subcommittee SC 5 "Milk and milk products" (secretariat: NEN, Netherlands) of the International Organization for Standardization (ISO) and has been adopted as EN ISO 9233:2013 by Technical Committee CEN/TC 302 "Milk and milk products - Methods of sampling and analysis" (secretariat: NEN, Netherlands). The committee responsible for this standard is NA 057-05-13 AA "Milch und Milcherzeugnisse - Probenahme- und Untersuchungsverfahren" ("Milk and milk products - Methods of sampling and analysis") at DIN.