EFHSS Questions and Answers - Question Q00031

Dear Sir/Madam,

1. Would like to know if enzyme is recommended for instrument wash.
2. Would appreciate your advice on the use of 20ml of phosphoric acid (dseclaing agent) to 40litres of water in the mainwash of a washer disinfector to remove white spots on the instruments coming from the impurites of cold water. Will the use of the phosphoric acid have any impact on the instruments under wash?

Best regards,
Savio Araujo,
Kuwait.

- Enzymatic washing in a machine is possible but the technical requirements of temperature, waterquality,moment of dosing, etc are very difficult to achieve.
- Add phosphoric acid to the main wash is very much to be advised against: acid products neutralise the activity of the alcalic detergents.
In the end there will be no wash result

Herwig Marien
Horeca-Laboservice MARIEN n.v.
Overwinningsstraat 20
B2610 Antwerp
Belgium
tel : +32 3 828 3636
fax : +32 3 828 2736
www.marien.be

Dear Mr. Renders,

thank you for your e-mail request about the use of enzymes and phosphoric acid in instrument washers.

1. Enzymes for instrument washers?
   pH-neutral, enzyme containing detergents have a better material protection in comparison to alka-line detergents, especially for anodized aluminium and optics. On the other hand, alkaline deter-gents with a pH-value of more than 10 have a better cleaning strength to remove stubborn OP-residues. These were the reasons, why we developed a new detergent for instrument washers which combines the high cleaning strength of alkaline detergents and the high material protection of pH-neutral enzyme containing detergents: neodisher mediclean, free of enzymes.
2. Phosphoric acid for the removal of water spots.
   We recommend a special washing program:
   • 400 ml of neodisher N or another phosphoric acid product, which is suitable for machine wash, to 40 litres of water, heating up to 50°C, 5 minutes washing-time, emptying of the tank.
   • intermediate rinse with water
   • final rinse with deionised water
   Pay attention: This program is suitable for chromium-nickel-steel and hardened chromium-steel, but not for other metals like aluminium, nickel or chromium plated instruments.

Yours faithfully

Chemische Fabrik DR. WEIGERT (GmbH & Co.)
Application department neodisher

Dr. Jürgen Staffeldt