NSF Protocol P448
Sanitization Performance of
Commercial Steam Generators
The Public
Health and Safety
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NSF Protocol P448
Sanitization Performance of Commercial Steam
Generators
NSF International
Consumer Products Program
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Copyright © 2014 NSF International
Prepared by NSF International staff with assistance from NSF Protocol Development
Panel members shown below:

Dr. Ratul Saha, Microbiologist, NSF International

Eric Downing, Falcon

Dr. Robert Powitz, Ph.D., MPH
Originated March 2014
Published by
NSF International, 789 N. Dixboro Road, Ann Arbor, Michigan 48105, USA
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Disclaimers
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integral part of NSF protocols. They are provided as general guidelines to the
manufacturer, regulatory agency, user, or certifying organization.
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Table of Contents
Table of Contents
1
General .....................................................................................................................................................3
1.1
1.2
1.3
1.4
Purpose ...................................................................................................................................... 3
Scope ......................................................................................................................................... 3
Limitations ................................................................................................................................ 3
Alternate materials, design, and construction............................................................................ 4
2
Normative References ..............................................................................................................................4
3
Definitions ................................................................................................................................................4
4
Requirements for Materials ......................................................................................................................5
4.1
4.2
4.3
4.4
Water / Steam Contact Surfaces ................................................................................................ 5
Sanitary Design ......................................................................................................................... 5
External Surfaces ....................................................................................................................... 5
De-scale Instructions / Safety Feature ....................................................................................... 5
4.4.1
Descaling ................................................................................................................................................5
4.4.2
Temperature Indicator ..........................................................................................................................5
5
Requirements for Performance .................................................................................................................6
5.1
Ability to Sanitize...................................................................................................................... 6
6
Requirements for Manufacturer’s Specifications .....................................................................................6
6.1
6.2
6.3
6.4
6.5
Third-Party Certifications.......................................................................................................... 6
Data Plate Specifications ........................................................................................................... 6
Marking ..................................................................................................................................... 6
Product Literature ...................................................................................................................... 7
EPA Device-Producing Establishment Number ........................................................................ 7
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NSF Protocol P448
Sanitization Performance of Commercial Steam Generators
1 General
1.1
Purpose
This protocol describes the requirements for the safety and effectiveness of commercial vapor
steam generators and their applicability to produce steam that could be used as a substitute for
chemical sanitizers.
1.2
Scope
The methods described in this protocol are intended to provide testing requirements and
acceptance criteria to certify that the steam created through the equipment is safe and effective
for use as a sanitizer.
NSF Protocol P448 is intended to certify steam generating equipment that sanitizes surfaces
which meet the requirements of the 2013 FDA Food Code Chapter 4 Section 7. The protocol sets
forth the following key elements:




1.3
Material requirements, indicating that the equipment is made of substances suitable for
use in food establishments, and designed to promote cleanability;
Labeling and product information requirements, to ensure that operating instructions are
clear and legible; that the instructions and device yield a suitable sanitizer; and the
product is designed for safe use;
Testing criteria that demonstrate the product achieves the active ingredient requirements
in the Food Code, and that it kills microorganisms at rates established by EPA and in the
Food Code.
Proof of electrical safety certification and EPA Device-Producing Establishment Number.
Limitations
The requirements of this protocol are limited to addressing the suitability, safety and
effectiveness of steam sanitizing equipment in a commercial setting. This protocol does not
establish performance requirements for energy efficiency, unit functionality, sanitization efficacy
on surfaces not included within the protocol or effects on surfaces.
The test method referenced in this protocol (MXXXX) is intended to be conducted without the
addition of any detergent or cleaning chemical. If the manufacturer suggests the use of a
detergent when cleaning a food-contact surface, the detergent should be an EPA-registered
pesticide and safe for incidental food-contact.
Certification to this protocol does not supersede the jurisdictional authority of regulatory
agencies. It shall be the applicant’s responsibility to determine their compliance with applicable
local, State and Federal regulations.
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1.4
Alternate materials, design, and construction
While specific materials, design, and construction may be stipulated in this Protocol, equipment
that incorporates alternate materials, design, or construction may be acceptable when such
equipment meets the intent of the applicable requirements herein.
2 Normative References
The following documents contain provisions that, through reference in this text, constitute
provisions of this protocol. At the time of publication, the indicated revisions were valid. All
standards are subject to revision, and parties are encouraged to investigate the possibility of
applying the most recent editions of the standards indicated below.
ASTM E1153-10 – Standard Test Method for Efficacy of Sanitizers Recommended for
Inanimate Non-Food contact Surfaces
ASTM E2315-08 – Standard Guide for Assessment of Antimicrobial Activity Using a Time-Kill
Procedure
Liza F. White, Dr Stephanie J. Dancer & Chris Robertson (2007): A microbiological evaluation
of hospital cleaning methods, International Journal of Environmental Health Research, 17:4,
285-295, Available online at: http://dx.doi.org/10.1080/09603120701372433
U. S. Food and Drug Administration – FDA Food Code 2013, Chapter 4 Section 7.
U. S. Food and Drug Administration - Bacterial Analytical Manual, March 2012. Available
online at:
http://www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManua
lBAM/default.htm.
3 Definitions
Terms used in this protocol that have a specific technical meaning are defined here.
capacity: The amount that the tank or reservoir can hold, expressed as a volume of water.
commercial: Non-residential.
detergent: A chemical or mixture of chemicals added to a cleaning unit to increase the cleaning
capacity if a steam generator.
easily cleanable: Manufactured such that soiling material may be removed by manual cleaning
methods.
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protocol: A written reference document that clearly states the objectives, goals, scope, and
procedures for a study.
manufacturer: The person or company that makes the original product.
sanitization: For the purpose of this protocol, it is the reduction in the viable count of the
selected microorganisms by 99.999% after application of the vapor cleaning unit
according to the manufacturer’s instructions, without detergent.
smooth: Free of pits and inclusions
water / steam contact surfaces: Exposed surfaces of a steam generator that are subject to water
or steam during normal use.
4 Requirements for Materials
4.1
Water / Steam Contact Surfaces
All water / steam contact surfaces shall be corrosion resistant. Water or steam contact surfaces
repeated exposed to water or steam are not required to be smooth.
4.2
Sanitary Design
Equipment shall be designed to prevent the accumulation of dirt and debris.
4.3
External Surfaces
Exterior surfaces exposed after assembly shall be smooth and easily cleanable.
4.4
4.4.1
De-scale Instructions / Safety Feature
Descaling
To maintain adequate function over time, units are required to have an alarm system that alerts
the operator when the unit requires descaling, or other necessary means of providing an effective
descaling efficacy indicator). Instructions for the descaling operation will be provided in the
parts and service manual.
4.4.2
Temperature Indicator
Units shall have a direct reading temperature indicator to monitor the temperature of the boiler.
The temperature indicator shall be readily visible to alert the operator when the temperature falls
below 290 degrees Fahrenheit.
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5 Requirements for Performance
5.1
Ability to Sanitize
This test method (MXXXX) is designed to evaluate whether the vapor steam generator can
effectively sanitize a surface.
The microbial removal/sanitization effectiveness of the commercial vapor steam generator shall
be evaluated on two different surface types. For practical application, stainless steel and ceramic
coupons shall be used. The steam generator shall be operated according to the manufacturer’s
instructions with static application.
The level of bacteria for each coupon must be reduced by a minimum of five logs (as compared
to the Positive Control Samples) for each test organism, including any bacterium recovered on a
cover cloth (if applicable). Additionally, the average plate count of the contact plates for each
bacterium must be less than or equal to 10 cfu/cm2.
6 Requirements for Manufacturer’s Specifications
6.1
Third-Party Certifications
All machines shall be certified by an ANSI-accredited third-party organization to meet the
applicable electrical safety standards.
6.2
Data Plate Specifications
The manufacturer of a commercial steam generator shall specify the following on a permanently
attached data plate:


6.3
Manufacturer’s name
Manufacturer’s model number
Marking
In addition to the requirements outlined in the NSF Certification Policies for NSF Protocols and
Non-NSF Standards, certified individual products, packaging materials, or promotional
information should bear the following information:
NSF Protocol P448
Sanitization Performance of Commercial
Steam Generators
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6.4
Product Literature
The manufacturer shall provide written instructions for the assembly, operation, and maintenance
of the machine.
The manufacturer’s literature shall state that only the sanitizing functions have been designed to
meet the requirements of this protocol for sanitization efficacy. There shall be no indication,
either directly or indirectly, that any other cycles on a certified machine have passed the
sanitization performance test.
6.5
EPA Device-Producing Establishment Number
The manufacturer shall provide evidence of the Device-Producing Establishment Number issued
by the U.S.E.P.A. as required under the provisions in 40CFR.
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