Neutralizing Buffer

Bob Friedel rfriedel at
Tue Mar 23 15:01:26 EST 1999

Difco, now owned by BBL (Cockeysville, Md) makes Neutralizing Buffer for the
verification of sanitization of equipment (per Standard Methods, Dairy &
APHA).  The formula is available commercially.  If you wish to make it up
yourself, you need the following:

Monopotassium Phosphate (0.0425g), Sodium Thiosulfate (0.16g) Aryl Sulfonate
Complex (5g), Sodium Hydroxide (0.008g)

Final pH 7.2 =/- 0.2 @ 25C.

If your looking for another formula for assessing the sanitary condition of
a variety of surfaces, you can also utilize Trypticase Soy Agar with
Lecithin (0.07%) & Tween 80 (0.5%) in conjunction with a  RODAC plate.
Another alternative is to make up the broth version and use it in
conjunction with a Calcium Alginate swab.

Pancreatic Digest of Casein (15g), Papaic Digest of Soybean Meal (5g),
Sodium Chloride (5g), Lecithin (0.7g), Tween 80 (5g), Agar (20.5g)

Final pH = 7.3 +/- 0.2 @ 25C

Robert R. Friedel
Quality Assurance Manager
Laboratory Research & Analysis Groups
Perritt Laboratories, Inc.
rfriedel at

Chuck Tilly wrote in message ...
>Does anyone out there happen to know of a formula for Neutralizing Buffer
>using Lecithin and Tween 80?  If you could provide my with a formula I
>greatly appreciate it.
>Thank You
>Chuck Tilly

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