SIST EN ISO 7218:2007/A1:2013

Microbiology of food and animal feeding stuffs - General requirements and guidance for microbiological examinations - Amendment 1 (ISO 7218:2007/Amd 1:2013)

This International Standard gives general requirements and guidance/options intended for three main uses: - implementation of ISO/TC 34/SC 9 or ISO/TC 34/SC 5 standards for detection or enumeration of microorganisms, named hereafter "specific standards"; - good laboratory practice for food microbiological laboratories (the purpose is not to detail them in this International Standard, manuals are available for that purpose); - guidance for accreditation of food microbiological laboratories (this International Standard describes the technical requirements according to Annex B of ISO/IEC 17025:2005 for the accreditation of a microbiological laboratory by national organizations). The requirements of this International Standard supersede the corresponding ones of existing specific standards.

Mikrobiologie von Lebensmitteln und Futtermitteln - Allgemeine Anforderungen und Leitlinien für mikrobiologische Untersuchungen - Änderung 1 (ISO 7218:2007/Amd 1:2013)

N/A

Microbiologie des aliments - Exigences générales et recommandations - Amendement 1 (ISO 7218:2007/Amd 1:2013)

Mikrobiologija živil in krme - Splošne zahteve in navodila za mikrobiološke preiskave - Dopolnilo A1 (ISO 7218:2007/Amd 1:2013)

Ta mednarodni standard opredeljuje splošne zahteve in navodila/možnosti za tri glavne načine uporabe: – izvajanje standardov ISO/TC 34/SC 9 ali ISO/TC 34/SC 5 za odkrivanje in štetje mikroorganizmov, v nadaljnjem besedilu »posebni standardi«, – dobra laboratorijska praksa za mikrobiološke laboratorije za preiskave živil (teh ta mednarodni standard ne opredeljuje, za to so na voljo priročniki); –navodila za akreditacijo mikrobioloških laboratorijev za preiskave živil (ta mednarodni standard opisuje tehnične zahteve iz Dodatka B standarda ISO/IEC 17025:2005 za akreditacijo mikrobiološkega laboratorija s strani državnih organizacij). Zahteve tega mednarodnega standarda nadomeščajo ustrezne zahteve obstoječih posebnih standardov.

General Information

• Status: Withdrawn
• Public Enquiry End Date: 19-Jan-2012
• Publication Date: 19-Nov-2013
• Withdrawal Date: 10-Jul-2024
• ICS: 07.100.30 - Food microbiology
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 11-Jul-2024
• Due Date: 03-Aug-2024
• Completion Date: 11-Jul-2024
• Ref Project: EN ISO 7218:2007/A1:2013 - Microbiology of food and animal feeding stuffs - General requirements and guidance for microbiological examinations - Amendment 1 (ISO 7218:2007/Amd 1:2013, Corrected version 2014-04-15)

Relations

• Amends: SIST EN ISO 7218:2007 - Microbiology of food and animal feeding stuffs - General requirements and guidance for microbiological examinations (ISO 7218:2007)
• Effective Date: 01-Dec-2013
• Revised: SIST EN ISO 7218:2024 - Microbiology of the food chain - General requirements and guidance for microbiological examinations (ISO 7218:2024)
• Effective Date: 21-Jan-2020

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2013
Mikrobiologija živil in krme - Splošne zahteve in navodila za mikrobiološke
preiskave - Dopolnilo A1 (ISO 7218:2007/Amd 1:2013)
Microbiology of food and animal feeding stuffs - General requirements and guidance for
microbiological examinations - Amendment 1 (ISO 7218:2007/Amd 1:2013)
Mikrobiologie von Lebensmitteln und Futtermitteln - Allgemeine Anforderungen und
Leitlinien für mikrobiologische Untersuchungen - Änderung 1 (ISO 7218:2007/Amd
1:2013)
Microbiologie des aliments - Exigences générales et recommandations - Amendement 1
(ISO 7218:2007/Amd 1:2013)
Ta slovenski standard je istoveten z: EN ISO 7218:2007/A1:2013
ICS:
07.100.30 Mikrobiologija živil Food microbiology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 7218:2007/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2013
ICS 07.100.30
English Version
Microbiology of food and animal feeding stuffs - General
requirements and guidance for microbiological examinations -
Amendment 1 (ISO 7218:2007/Amd 1:2013)
Microbiologie des aliments - Exigences générales et Mikrobiologie von Lebensmitteln und Futtermitteln -
recommandations - Amendement 1 (ISO 7218:2007/Amd Allgemeine Anforderungen und Leitlinien für
1:2013) mikrobiologische Untersuchungen - Änderung 1 (ISO
7218:2007/Amd 1:2013)
This amendment A1 modifies the European Standard EN ISO 7218:2007; it was approved by CEN on 15 June 2013.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this
amendment into the relevant national standard without any alteration. Up-to-date lists and bibliographical references concerning such
national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7218:2007/A1:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 7218:2007/A1:2013) has been prepared by Technical Committee ISO/TC 34 "Food
products" in collaboration with Technical Committee CEN/TC 275 “Food analysis - Horizontal methods” the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2014, and conflicting national standards shall be withdrawn
at the latest by February 2014
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 7218:2007/Amd 1:2013 has been approved by CEN as EN ISO 7218:2007/A1:2013 without
any modification.
INTERNATIONAL ISO
STANDARD 7218
Third edition
2007-08-15
AMENDMENT 1
2013-08-01
Microbiology of food and animal feeding
stuffs — General requirements and
guidance for microbiological
examinations
AMENDMENT 1
Microbiologie des aliments — Exigences générales et
recommandations
AMENDEMENT 1
Reference number
ISO 7218:2007/Amd.1:2013(E)
©
ISO 2013
ISO 7218:2007/Amd.1:2013(E)
©  ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 7218:2007/Amd.1:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2, www.iso.org/directives.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received, www.iso.org/patents.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO//TC 34, Food products, Subcommittee SC 9,
Microbiology.
ISO 7218:2007/Amd.1:2013(E)
Microbiology of food and animal feeding stuffs — General
requirements and guidance for microbiological examinations
AMENDMENT 1
Page 1, Clause 2
Delete ISO 8261. This has been superseded by ISO 6887-5 [already included in "ISO 6887 (all parts)"].
Delete the entries numbered "ISO 835 (all parts)", "ISO 8655-1", "ISO/TS 11133 (all parts)", and "ISO 16140"
and insert the following.
ISO 835, Laboratory glassware — Graduated pipettes
ISO 8655 (all parts), Piston-operated volumetric apparatus
ISO 11133, Microbiology of food, animal feed and water — Preparation, production, storage and
performance testing of culture media
ISO 16140-2, Microbiology of food and animal feed — Method validation — Part 2: Protocol for the
validation of alternative (proprietary) methods against a reference method
Pages 6 to 30, Clauses 5 and 6
Delete the existing text and insert the following.
5 Apparatus and equipment
5.1 General
In accordance with good laboratory practice, all apparatus and equipment should be kept clean and in good working
condition. Before use, equipment should be verified as fit for the intended purpose and its performance monitored during
use, where appropriate.
Where necessary, equipment and monitoring devices should be calibrated to traceable national standards, and
recalibration and any necessary intermediate checks performed, and procedures and results documented.
Equipment should be regularly checked and maintained to ensure safety and fitness for use. Equipment should be
monitored according to the working conditions and the accuracy demanded for the results.
The frequency of calibration and verification checks of each item of equipment is, in most cases, not specified
in this International Standard, since it shall be determined by each laboratory, depending on the type of
equipment and on the laboratory’s level of activity, and in accordance with the manufacturer’s instructions. In
a limited number of cases, a frequency has been specified since it was considered to be essential.
ISO 7218:2007/Amd.1:2013(E)
Apparatus and equipment shall be constructed and installed to facilitate operation and to allow for ease of
maintenance, cleaning, decontamination and calibration.
Any measurement uncertainties given in this clause relate to the apparatus and equipment concerned and not
to the whole method of analysis.
Throughout this clause, requirements for accuracy of measuring equipment are given. These are based on the
practical tolerance required to demonstrate suitable control of equipment in routine use. The accuracy stated
is related to the metrological uncertainty of the device (see ISO/IEC Guide 99).
For temperature control equipment, check the stability and homogeneity of the temperature before initial use
and after any repair or modification which might have an effect on the temperature control.
5.2 Protective cabinets
5.2.1 Description
A protective cabinet is a work station with horizontal or vertical laminar airflow to remove dust and other
particles, such as microbes, from the air.
The maximum tolerable number of particles per cubic metre with a size greater than or equal to 0,5 µm
represents the dust-spreading class of a safety cabinet. For cabinets used in food microbiology, the number of
particles shall not exceed 4 000 per cubic metre.
Cabinets for use in food microbiology laboratories are of four types.
a) Class I biosafety cabinets are open-fronted exhaust-protective cabinets that are intended to protect the
operator and the environment but will not protect the product from extraneous contamination. Potentially
infected aerosols will be contained within the cabinet and trapped by impaction on the filter. The filtered
air is normally discharged to the atmosphere; if this is not done, the air shall pass through two high-
efficiency particulate air (HEPA) filters mounted in series. They are not recommended for work with risk
category 3 pathogens because of the difficulties in maintaining and ensuring appropriate operator
protection.
b) Class II biosafety cabinets protect the product, the operator and the environment. They recirculate some
filtered air, exhaust some to the atmosphere and take in replacement air through the working aperture,
thereby providing operator protection. They are suitable for work with risk category 2 and 3 pathogens.
c) Horizontal laminar outflow cabinets protect the work from contamination, but blow any aerosols generated
into the operator’s face. Therefore they are not suitable for handling inoculated cultures or preparation of
tissue culture.
d) Vertical laminar airflow cabinets protect the product by the use of vertical laminar flow of HEPA-filtered air.
They also protect the operator by the use of internally recirculated air. They are particularly suitable for
providing an aseptic environment for handling sterile products and for protecting the operator when
handling powders.
Use protective cabinets for all work involving the handling of pathogens and contaminated powders, if required
by national regulations.
The use of a gas burner or wire incinerator is not recommended in protective cabinets. If it is necessary, the gas burner
should have a small flame so that the airflow is not disturbed. The use of disposable equipment (loops, pipettes, etc.) is a
suitable alternative.
5.2.2 Use
Use protective cabinets that are appropriate for the intended application and environmental conditions in the
laboratory.
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ISO 7218:2007/Amd.1:2013(E)
Cabinets should be kept as free of equipment as possible.
Where practicable, place everything needed inside the cabinet before starting work to minimize the number of
arm movements into and out of the working aperture. Position equipment and materials so as to minimize
disturbance to the airflow at the working aperture.
Operators should be adequately trained in the correct use of cabinets to ensure their safety and the integrity of the product
or culture.
5.2.3 Cleaning and disinfection
Clean and disinfect the working area after use with appropriate and non-corrosive disinfectant in accordance
with the manufacturer’s instructions. Regularly examine wire grids protecting prefilters, if they exist, and wipe
clean with a disinfectant-soaked cloth.
For laminar flow cabinets, the filter face should be vacuum cleaned regularly, taking care not to damage the filter
medium.
Safety cabinets should be fumigated before filter changing or servicing.
After cleaning of the cabinets, ultraviolet (UV) lamps may be used for disinfection. UV lamps should be regularly
cleaned and replaced in accordance with the manufacturer’s instructions. If they are used, they should be cleaned
regularly to remove any dust and dirt that may block the germicidal effectiveness of the light. Ultraviolet light intensity
should be checked when the cabinet is recertified to ensure that light emission is according to the manufacturer's
instructions.
See Reference [17].
5.2.4 Maintenance and inspection
The efficiency of a protective cabinet shall be checked by a qualified or certified person on receipt and
thereafter at regular intervals as recommended by the manufacturer, as well as after any repair or modification.
The efficiency should be checked after relocation.
Periodic verification of freedom from any microbial contamination should be carried out by a check of the working
surface and walls of the cabinet.
A periodic verification of the number of airborne microorganisms present should be carried out during operation of the
filters using the usual equipment. For example, expose several open Petri dishes containing a non-selective agar culture
medium (e.g. Plate Count Agar) in each cabinet for 30 min. Other methods may be used.
5.3 Balances and gravimetric diluters
5.3.1 Use and measurement uncertainty
Balances are mainly used for weighing the test portion of the sample to be examined and the components of
the culture media and reagents. In addition, they may be used for carrying out measurements of dilution fluid
volumes by mass.
Gravimetric diluters are electronic instruments consisting of a balance and programmable liquid dispenser and
are used during the preparation of initial sample suspensions; they function by adding diluent to a subsample
at a set ratio. The subsample is then weighed to the tolerance specified in the application, and the diluter set
to dispense sufficient diluent for the ratio required (e.g. 9 to 1 for decimal dilutions). See ISO 6887-1.
A food microbiology laboratory shall be equipped with balances of the required range and measurement
uncertainty for the different products to be weighed.
ISO 7218:2007/Amd.1:2013(E)
Unless otherwise stated, the resolution of the balance should achieve a tolerance of 1 % but shall be sufficient to
achieve a maximum tolerance of 5 % of the mass.
EXAMPLE To weigh 10 g, the balance should be capable of being read to 0,1 g.
To weigh 1 g, the balance should be capable of being read to 0,01 g.
Place the equipment on a stable horizontal surface, adjusted as necessary to ensure that it is level and
protected from vibration and draughts.
5.3.2 Cleaning and disinfection
Equipment should be cleaned and disinfected after use or following spillage during weighing with an appropriate and
non-corrosive disinfectant.
5.3.3 Performance verification and calibration
5.3.3.1 Calibration
Calibration shall be checked across the entire range by a qualified person at a frequency dependent on use.
5.3.3.2 Verification
The performance of the balance system shall be regularly verified during use and after cleaning with check
weights in the range of use by a qualified person.
NOTE Check weights may also be verified immediately after calibration of the balance.
5.4 Homogenizers, blenders and mixers
5.4.1 Description
This equipment is used to prepare the initial suspension from the test sample.
The following apparatus may be used:
⎯ a peristaltic blender with sterile bags, possibly with a device for adjusting speed and time; or
NOTE The Stomacher® is an example of a suitable product available commercially. This information is given for the
convenience of users of this document and does not constitute an endorsement by ISO of this product.
⎯ a rotary homogenizer (blender), the notional speed of which is between 8 000 r/min and 45 000 r/min inclusive, with
sterilizable bowls equipped with covers; or
⎯ a vibrational mixer with sterile bags; or
NOTE The Pulsifier® is an example of a suitable product available commercially. This information is given for the
convenience of users of this document and does not constitute an endorsement by ISO of this product.
⎯ another homogenizing system with equivalent efficiency.
In certain cases, manual mixing may be carried out using sterile glass beads having an appropriate diameter
(approximately 6 mm; see ISO 6887-2 to ISO 6887-5).
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ISO 7218:2007/Amd.1:2013(E)
5.4.2 Use
The usual operating time of a peristaltic homogenizer is 1 min to 3 min (see ISO 6887-2 to 6887-5 for specific
foods).
Do not use this type of apparatus for certain foodstuffs, such as:
⎯ products which risk puncturing the bag (presence of sharp, hard or dry particles);
⎯ products which are difficult to homogenize because of their texture (e.g. salami-type sausage).
The rotary homogenizer shall operate for a duration such that the total number of revolutions is
between 15 000 r/min and 20 000 r/min inclusive. Even with the slowest homogenizer, this time shall not
exceed 2,5 min.
The vibrational mixer may be used for most foodstuffs, including hard or dry products. The usual operating time
is 0,5 min to 1 min. If microorganisms are likely to be encountered deep inside cohesive structures, the sample should be
cut into small pieces prior to processing.
Glass beads can be used for the preparation, by shaking, of the initial suspensions of certain viscous or thick products, in
particular certain dairy products (see specific standards).
5.4.3 Cleaning and disinfection
Clean and disinfect peristaltic homogenizers and vibrational mixers regularly and after any bag spillage or
leakage.
For rotary homogenizers, clean and sterilize the glass or metal bowl after each use.
5.4.4 Maintenance
Inspect and maintain equipment in accordance with the manufacturer’s instructions.
5.5 pH meter
5.5.1 Description
A pH meter is used to measure the potential difference, at a determined temperature, between a measuring
electrode and a reference one, both electrodes being introduced into the product. It shall be capable of being
read to the nearest 0,01 pH unit, enabling measurements to be made with a tolerance of ±0,1 pH unit. The pH
meter shall be equipped with either manual or automatic temperature compensation.
NOTE The measuring electrode and the reference electrode are usually grouped together in a combined electrode system.
5.5.2 Use
A pH meter is used to measure the pH value of culture media and reagents to check if adjustment is needed
during preparation and as a quality check after sterilization.
It may also be used to measure the pH value of samples and sample suspensions. The use of a pH meter is discussed in
the standard specific to the product to be analysed, in which the conditions for the determination of the pH value and for
adjustment of the pH value are specified.
Adjust the pH meter as indicated in the manufacturer’s manual to measure the pH value at a standardized
temperature, e.g. 25 °C. Read the pH value after stabilization has been reached. Record the value to two
decimal places.
ISO 7218:2007/Amd.1:2013(E)
NOTE The reading may be considered stable when the pH value measured over a period of 5 s varies by not more than 0,02 pH
units. Using electrodes in good condition, equilibrium is normally achieved within 30 s.
5.5.3 Calibration and verification
5.5.3.1 Calibration
Calibrate the pH meter in accordance with the manufacturer’s instructions, using at least two, and preferably
three, standard buffer solutions at least daily before use. Define the maximum permissible tolerances for these
readings, which shall be more stringent than the tolerance permitted in general use.
The standard solutions should be traceable and shall have pH values specified to two decimal places at the
measurement temperature (in general, pH 7,00 and pH 4,00 and/or pH 9,00 at 25 °C, in accordance with the
manufacturer’s instructions). The standards used shall encompass the pH value to be measured.
5.5.3.2 Verification
After calibration of the pH meter with the two traceable standard buffer solutions, a third buffer standard solution should
be used to perform a check reading (in “read” mode) to demonstrate the functionality of the pH meter.
If readings fall outside the maximum permissible limits adjust the pH meter in accordance with the
manufacturer’s instructions. This adjustment shall be followed by further calibration and check.
5.5.4 Maintenance
Check and maintain the electrodes in accordance with the manufacturer’s instructions. It is necessary, in
particular, to monitor regularly
⎯ the condition of the electrodes with respect to ageing and soiling; and
⎯ the response time and stability.
Rinse the electrodes with distilled or deionized water after each use. In order to take into account the soiling
and ageing of the electrodes, regularly clean them more thoroughly in accordance with the manufacturer’s
instructions.
Store the electrodes in accordance with the manufacturer’s instructions.
5.6 Autoclave
5.6.1 Description
An autoclave enables a saturated steam temperature to be attained in the chamber.
The autoclave should be equipped with
⎯ at least one safety valve;
⎯ a drain cock;
⎯ a regulation device allowing the temperature in the chamber to be maintained to within ±3 °C of the target
temperature (to take into account the measurement uncertainty associated with the measuring thermocouple); and
⎯ a temperature probe or a recording thermocouple.
It should also be equipped with a timer and temperature recorder.
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ISO 7218:2007/Amd.1:2013(E)
5.6.2 Use
With steam sterilization, all air is expelled prior to the pressure build-up. If the autoclave is not fitted with an
automatic evacuation device, it is necessary to remove the air until a continuous jet of steam is emitted.
For the sterilization of culture media, the saturated steam in the chamber shall be at a temperature of at least
121 °C ± 3 °C or temperature specified by manufacturers or production instructions or specified in the test
method.
For the destruction of cultured microorganisms and decontamination of used culture media, the saturated
steam in the chamber shall be at a temperature of at least 121 °C ± 3 °C.
During the same sterilization cycle, do not use the autoclave to sterilize clean equipment (and/or culture
media) and at the same time to decontaminate used equipment (and/or used culture media).
It is preferable to use separate autoclaves for these two processes. After autoclaving, all materials and equipment should
be allowed to cool within the autoclave before removal.
For safety reasons, do not remove the contents until the temperature has dropped below approximately 80 °C.
5.6.3 Maintenance
Clean the chamber, drain filter and door seals regularly. Check the door seals for integrity. Carry out draining
operations and descaling, if necessary, at regular intervals. Follow the manufacturer’s recommendations.
5.6.4 Verification
The autoclave shall be kept in good operating condition and shall be regularly inspected by competent
qualified personnel in accordance with the manufacturer’s instructions.
Keep the monitoring instruments in good working order and verify them by calibration and regular checks.
Initial validation should include performance studies for each operating cycle and each load configuration used in
practice. This process should be repeated after significant repair or modification. Sufficient temperature sensors should
be positioned within the load to demonstrate adequate heat penetration at all locations. Validation and revalidation should
consider the suitability of heat-up and cool-down times as well as the sterilization temperature.
For each load, as a minimum, a process indicator should be included at the centre of the load to verify the heating process
where a traceable record of process efficiency is not available.
5.7 Media preparator
5.7.1 Description
A media preparator is principally designed for the sterilization of large volumes of media (>1 l). It consists of a
heating vessel, water jacket and continuous stirring device. The equipment shall also be fitted with a
temperature gauge, pressure gauge, timer and safety valve.
In addition, the unit should have a safety lock to prevent opening until a temperature of <80 °C is reached.
5.7.2 Use
Follow the manufacturer’s instructions at all times.
The entire production process takes place within the apparatus. After addition of all the ingredients, they are
dissolved by stirring and heating. This is followed by sterilization.
ISO 7218:2007/Amd.1:2013(E)
5.7.3 Maintenance
Wash the preparator and rinse thoroughly with purified water between each media batch.
5.7.4 Verification
The preparator shall be kept in good working condition and inspected regularly by competent qualified
personnel in accordance with the manufacturer’s instructions.
Keep the monitoring instruments in good working order and verify them by calibration and regular checks.
Initial validation should include performance studies for each operating cycle and each load size used in practice. This
process should be repeated after significant repair or modification. Two temperature probes, one adjacent to the control
probe and another remote from it, may be used to demonstrate uniform heating.
The temperature and duration of each cycle should be checked.
5.8 Incubator
5.8.1 Description
An incubator consists of an insulated chamber which enables the temperature to be kept stable and uniformly
distributed to within the maximum permissible temperature tolerance specified in the test method.
5.8.2 Use
Incubators shall be equipped with a regulation system that allows the temperature or other parameters to be
kept even and stable over their entire working volume. Define the working volume to ensure that this is
achieved.
If the ambient temperature is close to or higher than that of the incubator, it is necessary to fit a cooling
system to the chamber.
The walls of incubators should be protected from sunlight.
If possible, incubators should not be completely filled in a single operation because the culture media will take a long
time to come to temperature equilibrium, whatever type of incubator is used (forced-air convection or otherwise). Refrain
from leaving the incubator door open for long periods.
When loading incubators, attention should be paid to air circulation (see 10.2.5).
5.8.3 Cleaning and sanitization
Clean and sanitize regularly the inner and outer walls of the incubator and, if appropriate, remove dust from
the ventilation system.
5.8.4 Verification
Check the temperature stability and the homogeneity of the temperature distribution at the working
temperature(s) throughout the working volume of the incubator through simultaneous use of a number of
thermometers or thermocouples of known accuracy and appropriate temperature range.
Use the information to define the acceptable operating range of the incubator and the optimum position of the
thermometer or recording thermocouple used to monitor working temperatures.
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ISO 7218:2007/Amd.1:2013(E)
For example, to achieve a target temperature of (37 ± 1) °C when the profiling data shows a range of 36,8 °C to 37,3 °C
across the incubator, then the operating range should be reduced to 36,2 °C to 37,7 °C in order to ensure all parts of the
incubator achieve the target temperature of 37 °C.
This process should be repeated after each significant repair or modification.
The temperature of operation should be checked with one or more maximum and minimum thermometers or recording
thermocouples, for example.
Check the incubator temperature at least every working day. For this purpose, each incubator shall
incorporate at least one working measurement device, which can be immersed in glycerol (or other appropriate heat
sink). Other checking systems of equivalent performance may be used.
5.9 Refrigerator, cold-storage room
5.9.1 Description
These are chambers which allow maintenance of cold storage. For the conservation of food samples for
analysis, the temperature shall be (3 ± 2) °C (maximum permissible tolerances), except for particular
applications. For other uses, the temperature, unless otherwise specified, shall be (5 ± 3) °C.
5.9.2 Use
In order to avoid cross-contamination, use different chambers, or at least different containers, to achieve
physical separation, for the storage of
⎯ uninoculated culture media and reagents;
⎯ test samples; and
⎯ microorganism cultures and incubated media.
Load refrigerators, chillers and cold-storage rooms in such a way that appropriate air circulation is maintained
and the potential for cross-contamination is minimized.
5.9.3 Verification
Check the temperature of each chamber each working day using a thermometer or a permanently installed
probe. The accuracy required of the temperature-monitoring device is dependent on the purpose for which the
unit is used.
5.9.4 Maintenance and cleaning
Carry out the following maintenance operations at regular intervals to ensure proper operation:
⎯ removal of dust from the motor blades or from the external heat-exchange plates;
⎯ defrosting;
⎯ cleaning and sanitization of the inside of the chambers.
5.10 Freezer and deep freezer
5.10.1 Description
A freezer is a chamber which allows frozen storage to be guaranteed. The temperature, unless otherwise
specified, shall be below −15 °C, preferably below −18 °C for food samples.
ISO 7218:2007/Amd.1:2013(E)
A deep freezer is a chamber which allows deep-frozen storage to be guaranteed. The temperature, unless
otherwise specified, shall be below −70 °C.
5.10.2 Use
5.10.2.1 Freezer
Different chambers, or at least different containers, shall be available to achieve physical separation for the
storage of
⎯ uninoculated reagents;
⎯ samples for analysis; and
⎯ microorganism cultures.
Load the freezer in such a way that a sufficiently low temperature is maintained, in particular when unfrozen
products are introduced.
5.10.2.2 Deep freezer
The principle use is storage of microorganisms, reference and/or working cultures, and reagents.
Load the freezer in such a way that a sufficiently low temperature is maintained and cross-contamination
between microorganisms and reagents is prevented.
5.10.3 Verification
Check the temperature of each chamber regularly using a suitable temperature-monitoring device.
5.10.4 Maintenance
Carry out regularly the following maintenance operations:
⎯ removal of dust from the motor blades and from the external heat-exchange plates (if accessible);
⎯ defrosting;
⎯ cleaning and sanitization of the inside of the chambers.
5.11 Thermostatically controlled bath
5.11.1 Description
A thermostatically controlled bath, filled with a liquid (water, ethylene glycol, etc.), with or without a fitted lid or
other device to limit evaporation, is required to maintain a specified temperature. Temperature control is often
more precise than an air incubator, enabling maximum permissible tolerance of ±0,5 °C or better to be
achieved. The working temperatures and required maximum permissible tolerance are stipulated in each
individual application or standard method. A cooling system is necessary to maintain a temperature near or
below ambient temperature.
5.11.2 Use
The main uses are as follows:
⎯ incubation at a constant temperature of inoculated culture media;
10 © ISO 2013 – All rights reserved

ISO 7218:2007/Amd.1:2013(E)
⎯ maintenance of sterile molten agar media during media preparation;
⎯ tempering of sterile molten agar media for use in specific standard methods;
⎯ preparation of initial sample suspensions or solutions at a controlled temperature;
⎯ heat treatment of initial sample suspensions at a controlled temperature (e.g. pasteurization).
Where precise temperature control is required, the bath shall be equipped with a circulating-water pump and
an automatic temperature-regulation system. Any agitation of the liquid shall not cause droplet dispersal.
Lidded baths are preferable for precise or high-temperature usage. Sloping lids that allow condensate to drain should be
used.
For incubation of inoculated media, maintain the liquid level so that the top of the test medium is at least 2 cm
below the liquid level in the bath throughout the incubation.
Other containers should be placed within baths such that the level of their contents is below that of the liquid.
The depth of immersion shall preclude entry of water through the closure.
Devices to maintain stability of the containers may be required, for example racks.
All containers should be dried after removal from the bath and before further use.
5.11.3 Verification
Check the stability and homogeneity of the temperature throughout the bath before initial use and after any
repair or modification having an effect on the temperature control.
Monitor each bath with a thermometer, thermocouple or temperature-recording device of suitable minimum
measurement uncertainty (see 5.28.2), and independent of the automatic temperature-regulation system.
NOTE A digital display can also be used, provided that its accuracy and resolution are verified.
Monitor the temperature of the bath during each use and at least daily for periods of extended incubation.
5.11.4 Maintenance
Baths should be filled with liquid as recommended by the manufacturer. For incubation of cultures, distilled or deionized
water should preferably be used.
Check regularly the level of the liquid to ensure the correct functioning of the bath and satisfactory immersion
of items in the bath. The liquid level shall always cover the heating elements.
Baths should be emptied, cleaned, sanitized and refilled regularly and at a frequency depending on usage, or after a
spillage occurs.
5.12 Steamers, including boiling-water baths
5.12.1 Description
Steamers and boiling-water baths consist of a heating element surrounded by water in a vessel with a close-
fitting lid. In a steamer, this creates steam at atmospheric pressure; in a boiling-water bath this heats the water
to a temperature at or close to the boiling point, with or without the production of steam.
ISO 7218:2007/Amd.1:2013(E)
5.12.2 Use
The main uses are as follows:
⎯ melting of agar media;
⎯ preparation of heat-labile media;
⎯ reduction of contamination of small items of equipment between use.
A safe and adequate level of water shall be present in the vessel to ensure that the heating elements are
covered at all times.
An autoclave with a free-steaming facility may also be used.
5.12.3 Maintenance
Keep steamers and boiling water baths clean.
If necessary, regular descaling should be performed at a frequency dependent on local water hardness.
5.13 Sterilizing oven
5.13.1 Description
A sterilizing oven is a chamber that is capable of maintaining a temperature of 160 °C to 180 °C for the
destruction of microorganisms by dry heat.
5.13.2 Use
Only robust equipment such as glass and metalware shall be sterilized in the sterilizing oven; do not use it for
plastic and rubber items.
Before sterilization, clean all glassware and metalware to be sterilized in the oven.
If volumetric glassware is sterilized in the sterilizing oven, verify regularly the accuracy of marked volumes.
The temperature shall be uniform throughout the chamber. The oven shall be equipped with a thermostat and
a thermometer or temperature-recording device of suitable accuracy.
It should be equipped with a duration indicator, programmer or timer.
Once the operating temperature is reached, the sterilizing procedure shall last for at least 1 h at 170 °C ±
10°C or an equivalent time/temperature combination.
After sterilization, to prevent cracking, glassware should be allowed to cool in the oven before removal.
5.13.3 Verification
Check the stability and homogeneity of the temperature throughout the oven before initial use and after any
repair or modification which might have an effect on the temperature control.
The oven shall be fitted with a calibrated thermometer, thermocouple or temperature-recording device of
suitable accuracy which is independent of the automatic temperature-regulation system. The monitoring
device shall have a resolution of 1 °C or better at the oven temperature used.
The temperature of the oven should be monitored and recorded during each use.
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ISO 7218:2007/Amd.1:2013(E)
5.13.4 Maintenance
Clean internal surfaces when required.
5.14 Microwave oven
5.14.1 Description
A microwave oven is a device that allows heating of items by microwave energy at atmospheric pressure.
5.14.2 Use
Use the equipment currently available only to heat liquids or melt agar culture media.
WARNING — Do not heat media containing heat-sensitive components in a microwave unless it has
been verified that this way of heating has no effect on medium performance. No assessment has yet
been made of the efficiency of microwaves for sterilizing culture media and microwave ovens shall not
be used for this purpose.
The oven shall be capable of heating liquids and culture media in a controlled manner via a microwave
emission cycle. The distribution of microwaves shall be homogeneous to avoid zones of overheating. Ovens
fitted with a turntable or a stirrer for the microwaves give better heat distribution.
Do not use metal equipment, including metal closures. Loosen bottle caps or stoppers before heating.
Heating for longer periods at lower power ratings can give better heat distribution.
WARNING — Handle heated items with care. Contents can become super-heated and boil out or
bottles can explode.
When melting agar media, a low power setting (e.g. defrost cycle) and a water heat sink (e.g. 50 ml to 100 ml of water in
a microwaveable beaker) are recommended to aid control of the heating process.
A standing time of at least 5 min is recommended after the heating process before removal from the microwave oven.
5.14.3 Verification
Suitable heating times and power settings shall be established at initial commissioning for the different
volumes of liquids and culture media routinely handled, to ensure optimum performance and avoid
overheating of sensitive products.
5.14.4 Maintenance
Clean the oven immediately any spillage occurs, as well as at regular intervals dependent on usage.
Oven door seals should be inspected for integrity and the oven checked for radiation leakage at regular intervals with a
probe or equivalent device according to the manufacturer's instructions.
5.15 Glass washer
5.15.1 Description
Laboratory glass washers are electronically controlled machines for washing general laboratory glassware,
which can be programmed for different washing cycles and rinses (e.g. distilled or deionized water or acid).
Devices for washing glass pipettes are special glass washers designed to clean the narrow bores of pipettes.
ISO 7218:2007/Amd.1:2013(E)
5.15.2 Use
Many types of glass washer are available, and these shall generally be installed and used following the
manufacturer’s instructions.
5.15.3 Verification
Check the effectiveness of cleaning by visual inspection and, in critical applications, carry out tests to ensure
that glassware is free from inhibitory substances.
Alkaline or acidic residues may be checked for by using a universal pH indicator solution; a pH within the range 6,5
to 7,3 should be achieved.
5.15.4 Maintenance
Progamme regular maintenance as specified by the manufacturer at a suitable frequency.
More frequent servicing may be required for heavily used equipment or in hard water areas.
5.16 Optical microscope
5.16.1 Description
There are several different types of microscope: monocular, binocular, with a visual display unit, a camera or
fluorescence equipment, etc., and with an internal or external light source. For bacteriological examinations,
objectives with magnifications from ×10 (dry lens) to about ×100 (oil immersion with spring-loaded turret) are
used to obtain an overall magnification of ×100 to ×1 000. Phase contrast and dark field microscopy are also
invaluable for examination of “wet preparations”.
5.16.2 Use
Set up the optics of the microscope in accordance with the manufacturer’s instructions. The optical axis of the
light from the high-intensity light bulb shall pass through the centre of the substage condenser, the slide and
the object lens to the eyepiece so that sphe
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