| NMKL newsletter |
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| Nr. 48/01, December 2001 | ||
NMKL
is arranging courses in
Uncertainty of measurement in microbiological testing of foods
There has been considerable interest in the NMKL courses in uncertainty of measurement within microbiological analysis. Chemists have been assessing uncertainty of measurement for some years, but the topic is relatively new within microbiology.
Professor Eysteins Skjerve lectures in
measurement uncertainty
Professor Eystein Skjerve,
Norwegian School of Veterinary Science and author of NMKL procedure no 8 (1999):
“Measurement of uncertainty in microbiological
examination of foods” lectures in all the Nordic countries on the principles
of application of uncertainty of measurement in quantitative microbiological
examinations of foods. To give participants the greatest benefit, a part of each
course is organized as a workshop, involving group exercises. For this reason,
the number participating in each course is restricted to about 40.
The courses arranged in
Norway Sweden and Denmark in were all quickly fully subscribed, with many
additional names on the waiting list. When all the courses have been completed,
an evaluation will be made as to whether similar and/or follow-up courses will
be arranged.
Invitations
have been sent to Finnish and Icelandic NMKL subscribers and addresses on
NMKL’s mailing list. Courses are to be held on January 9th 2002 at
the Environmental and Food Agency of Iceland (Hollustuvernd Ríkisins), and
January 30th 2002 at the National
Veterinary and Food Research Institute (Eläinlääkintä- ja
elintarviketutkimuslaitos, EELA) in Helsinki. See www.nmkl.org for programme and
registration.
An Excel spread sheet for calculations to be used in the estimation of uncertainty of measurement has been prepared, in connection with NMKL procedure no 8. This spread sheet is a useful tool and can be downloaded free of charge from NMKL’s homepage, link course/seminar.
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NMKL method no 5, 5th Ed. 2001:Aerobic microorganisms and
presumptive Entero-bacteriaceae.
Enumeration on surfaces and utensils. |
NMKL method No 10, 3. ed., 2001: Gravimetric determination of fat in milk, cream and
milk powder. |
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In 1998 Special Research Officer Gun Wirtanen, VTT, Technical Research
Centre of Finland was appointed as a referee to revise NMKL method no 5, 4th
Ed., 1987: Microbes,
total number. Determination with the swab method or contact plate method
on utensils in contact with food. Janne Lundén, University
of Finland, Faculty of Veterinary Medicine has been Wirtanen’s
co-referee. Enumeration of aerobic microorganisms and presumptive Enterobacteriaceae
using cotton swabs or using contact agar plates on surfaces in food
processing and production areas, as well as in catering, does not give the
absolute number of bacteria. It gives an estimate of the hygienic
standard. During the period Wirtanen was revising the NMKL method, she arranged a
Nordic collaborative validation on the method of aerobic microorganisms
under VTT’s direction, with traditional contact plates as well as a
commercially available contact plates. The study has been published in
Journal of AOAC International 83, 1357-1365. |
At the annual meeting in 1997, NMKL agreed to
the withdrawal of method No 10 2nd Ed., 1977. In place of this
one method, users have to apply several IDF (International Dairy
Federation) standards. It was therefore decided to revise method no 10 to
harmonize with the IDF standards. In 1998, Erik Wolthers and Leif Bøgh-Sørensen,
Danish Veterinary and Food Administration were appointed as referees. Wolthers and Bøgh-Sørensen have revised the
method with respect to several collaboratively validated IDF standards,
principally IDF 1D: 1996, IDF 16C:1987, IDF 9C:1987. The method is definitive for the quantitative
determination of fat content in milk, cream and milk powder. An ammoniacal ethanolic solution of the test sample is extracted with
diethyl ether and light petroleum. The solvents are removed by
distillation or evaporation, and the weight of the extracted substances
determined. (This is usually known as the Röse-Gottlieb method). |
NMKL would like to thank the referees and their institutes for their extensive work in the elaboration of these NMKL methods.
Methods
withdrawn
At
the 55th Annual Meeting, NMKL decided to withdraw the following
methods from its method collection:
No
20 , 2nd Ed. 1982: Methods for microbiological examinations of
butter.
No
101, 1982: Aflatoxins. Detection with mini-column.
Changes
in NMKL method 163, 1998: Pathogenic
Yersinia enterocolitica. PCR methods for detection in foods
Susanne Thisted Lambertz, one of the referees of NMKL method no 163, has
informed that item 5.2 in part A of the method required revision, as the
solution Bact-Xtractor is no longer produced. NMKL has approved the replacement
of item 5.2 in part A, in method No 163, 1998 with the following text:
5.2 Percollâ (Amersham Pharmacia Biotec AB)
Prepare a 100% solution:
Percoll 100 mL
NaCl
0.85 g
Mix and sterile filter. (Note! Percoll is not to be autoclaved) Store at
4-8 °C.
50% Percoll solution: dilute the 100% solution with
sterile saline solution.
A
Nordic working group consisting of:
Denmark:
Berit Behbahni, Veterinary and Food Administration, Nordøstsjælland
Finland:
Tuula Lakso, Helsinki City Environment Centre
Iceland
Páll Steinþórsson, Icelandic Fisheries Laboratories
Norway:
Anne Grændsen, Norwegian Institute for Food and Environmental Analysis
Sweden:
Annelie Eklöw, Arla FoU
has drawn up an NMKL procedure describing a control
programme and control methods, to be applied to the preparation of
microbiological media in a quality assured laboratory. The procedure includes
both solid and liquid media in the following categories:
·
Commercial
ready-to-use media
·
Media prepared from
commercially available dehydrated media
·
Media prepared from
scratch (single components)
In many situations, it is essential that the media
give reproducible results. In order to document satisfactory quality of media,
the laboratory must refer to an established quality control program.
NMKL would like to thank the project group and
particularly Anne Grændsen, Norsk Matanalyse, for drawing up this procedure,
which will be published in Norwegian very shortly.
Recently
published in Swedish:
NMKL procedure no 9, 2001: Evaluation
of results derived from the analysis of certified reference materials.
This
NMKL procedure is now also available in Swedish. The English version of the
procedure was published in March this year and a presentation of the procedure
was given in NMKL newsletter no 46/01. The use of certified reference materials
is an important aspect of quality assurance. The procedure describes the
evaluation of certified reference materials, how to detect systematic and random
errors by use of several reference materials, how to assess the z-score etc.
The NMKL working group who elaborated this procedure
consisted of the following members:
Denmark:
Erik Huusfeldt-Larsen, Danish Veterinary and Food Administration
Finland:
Reino Kario, The Customs Laboratory
Iceland:
Kristín Ólafsdóttir, Rannsóknastofa i Lyfjafræði, University of
Iceland
Norway:
Kåre Julshamn, Directorate of Fisheries
Sweden:
Lars Jorhem, National Food Administration (project leader)
NMKL would like to thank the project group and in
particular Lars Jorhem, the author of the procedure, who also translated the
procedure into Swedish.
NMKL’s collaboratively validated methods are
considered for revision every 10 years. Other method are reviewed every 5 years
or when necessary.
NMKL has decided that NMKL procedures are to be
considered for revision for first time after 2 years, then every 5th
year or when necessary.
New edition of NMKL report no 11, 2nd
ed. 2000:
“Guide
for referees within chemical analysis
– elaboration of methods within NMKL”
NMKL report no 11, 2. Ed. 2000 has been
reprinted, as two pages (page 13 and 28) were missing from the first printing.
The report has been distributed to NMKL’s
referees and members.
National Veterinary Institute (VI) was
established in 1891 and is a leading research establishment and centre of
expertise for diagnostic work in the diseases of animals (including fish) and
infectious agents and contaminants in foodstuffs and animal feed. VI is a
governmental institute under the Ministry of Agriculture, and is controlled by
the division of food production and health.
In 1994, VI started to work on establishing a
new department for food analysis. The reason was that the Norwegian Food Control
Authority became a purely administrative institution in 1995, and transferred
its chemistry and microbiology laboratories to VI. In the same year the Food
Control Authority was relocated to the same location as VI, at Adamstuen in
Oslo, and the VI’s department on food and feed hygiene was established. Today,
the department has 68 employees, including 14 doctoral candidates. VI has a
total of 309 employees, of which approximately 200 are at the VI in Oslo.
The Veterinary Institute is organized as
following:
Priority areas within food analysis:
Thor
Waaler at the “metal lab”, section for chemistry
Reference function:
As the Norwegian Food Control Authority no longer has
its own laboratory, the Authority has delegated reference functions to certain
research and analytical institutions. The department of food and feed hygiene at
VI has a reference function in several parameters (18 chemical and 12
bacteriological). This involves the development and use of complex analytical
methods, advisory consulting in connection with this, establishing working and
control routines for quality assurance of the work within a laboratory,
international cooperation with similar institutions and last but not least,
cooperation with other institutions in Norway with reference duty for food
analysis. VI has a specific coordinating function, and therefore hosts the
secretariat of the Norwegian National Committee within NMKL. In 1997, when it
was Norway’s turn to host the NMKL General Secretariat, VI was a natural
choice as host. The Institute was also willing to extend this relationship for
an additional 4 year period, until October 2005. VI also contributes its
expertise to NMKL, as personnel are members of the Norwegian National Committee,
as well as being referees, co-referees, contact persons and project members.
Research projects in progress:
The department has extensive research interests. In
2001, there are
15 projects are financed by the Norwegian Research
Council (NFR),
3 strategic institute programmes financed by the NFR
and
2 EU projects.
These projects are within the areas of:
Gro Johannessen working at the method
performance study on staph.eur? Gro is referee on 3 NMKL topics.
Surveillance programs in progress:
The Norwegian Food Control Authority has 11 projects
in progress, including:
From
the laboratory at the section for food and feed microbiology
National and international work:
Personnel from the department have honorary
appointments to the NFR and are also members of national scientific committees
and councils. International for a include NMKL, NordVal, CEN, ISO, Codex
Alimentarius, Scientific Committee on Toxicity, Ecotoxicity and the Environment
(SCTEE).
For further information about VI and VI’s numerous
activities please visit: www.vetinst.org
NMKL’s 55th Annual Meeting 2001, at
Lillehammer, 25-28 August, 2001.
The Norwegian National Committee invited NMKL’s
members to hold their 55th Annual Meeting in the beautiful and
historical surroundings of Lillehammer’s open air museum, Maihaugen.
At NMKL’s Annual Meetings there are both plenary
sessions and sessions for work in sub-committees. At the plenary sessions, NMKLs
affiliates and invited guests of NMKLs most important co-operators give updates
of activities. NMKL activities, method topics and the different projects are
discussed extensively in the 4 sub-committes:
·
Sub-committee 1:
administration, led by Ole Bjørn Jensen, Denmark
·
Sub-committee 2:
microbiology, led by Dr. Maija Hatakka, Finland
·
Sub-committee 3:
chemistry, led by Dr. Kåre Julshamn, Norway
·
Sub-committee 4:
sensory,
led by Dr. Halina Agerhem, Sweden
Kirkestuen, where the sub-committee meetings took place
The chairmen of sub-committees 1 (also NMKL chairman)
and 3, Ole Bjørn Jensen and Kåre Julshamn, together with secretary-general,
Hilde Skår Norli, were re-elected for a new 4-year period.
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| Managing Director Ole Bjørn Jensen, Scanpharm, Denmark, was re-elected as chairman for sub-committee 1 and for NMKL for a new 4 year period. | Professor Kåre Julshamn, Directorate of Fisheries Institute for Nutrition, Norway, was re-elected as chairman for sub-committee 3, chemistry. |
Hilde Skår Norli, National Veterinary Institute, Norway, was re-elected as NMKL’s secretary-general for a new 4 year period. |
Nine new method topics have been raised since the
last annual meeting. One referee has been appointed in chemistry, 7 in
microbiology and one in sensory.
All
the topics in NMKL’s working program (approximately 60) were reviewed at the
meeting – see NMKL’s home-page for an updated working schedule.
Methods approved for printing:
·
Coliform bacteria, thermotolerant. Enumeration
in foods. (Rev. of NMKL no. 125, 3rd ed., 1996)
· Bacterial count. Determination by direct epifluorescent filter technique (DEFT) in raw minced meat. (Rev. of NMKL no. 137, 1990)
·
Bacteriological examination of fresh and frozen seafood. (Rev.
of NMKL no. 96, 2nd ed., 1994)
·
Antibacterial substances. Detection by a
microbiological method in kidney and muscle from slaughter animals. (Rev.
of NMKL no. 121, 1987)
·
Nitrogen. Determination in foods and feeds according to Kjeldahl.
(Rev. of NMKL no. 6, 1976)
· Mercury. Determination by flow injection cold vapour atomic absorption spectrometry (FI-CVAAS) after microwave digestion.
· Ergosterol. LC determination in grain.
From
a meeting of sub-committee 3.
Members of the Norwegian National Committee: from left: Marit Rødbotten, Liv Marit Rørvik, Gudrun Q. Rognerud Urd Bente Anderssen, Tone Normann Asp.
NMKL’s
Working Plan
The 55th Annual Meeting of NMKL also approved a new working plan. This defines NMKL’s activities, the duties of the involved personnel, and the currect procedures. The plan is available on www.nmkl.org.
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Nordic
and international partners This year, NMKL had the pleasure of welcoming representatives from EK-Liv’s working group’s secretariat, the Nordic Group for Food Control (NNK), the Nordic working group for Toxicology and Risk Assessment (NNT) and the Nordic working group for Food Microbiology (NNM) respectively, who all presented reports of their work. The following were also represented, and gave reports: NordVal, CEN, AOAC INTERNATIONAL and IDF (International Dairy Federation).
Agreement
of Cooperation with NordVal The Annual Meeting 2001 approved an agreement of cooperation between NMKL and NordVal. NordVal is a Nordic organisation for the validation of alternative microbiological methods (test kits). They were established at NMKL’s suggestion, when NMKL decided to only validate methods where all the reagents are stated in the method. As mentioned in the previous NMKL News, NordVal are now well-established. The agreement of cooperation with NordVal comprises a mutual exchange of information, together with NMKL agreeing to give out information on NordVal, and which kits they have validated. This is to be continued until NordVal have their own website.
See
NMKL’s website for information on NordVal, and the kits which are
validated. http://www.nmkl.org/nordval.htm |
Agreement
of Cooperation with AOAC INTERNATIONAL NMKL has recently renewed its agreement of cooperation with AOAC INTERNATIONAL, which consists of exchange of information, participation at each other’s annual meetings and the possibility of the mutual adoption of each other’s methods, to avoid unnecessary double work. When AOAC INTERNATIONAL adopt NMKL methods, they are to be referred to as NMKL-AOAC methods. If NMKL adopts AOAC INTERNATIONAL methods, they are to be referred to as AOAC-NMKL methods.
Agreement
with AOAC INTERNATIONAL on Publication of microbiological methods NMKL
has also entered into an agreement with AOAC INTERNATIONAL concerning
publication of NMKL microbiological methods on their CD-ROM
Compendium, containing several microbiological methods. NMKL methods will
be published in NMKL format, with the NMKL logo. Why
doesn’t NMKL publish its methods on CD-ROM? Sub-committee 1 has discussed whether NMKL should make its methods collection available on CD-ROM. The disadvantage of using CD-ROM is that it becomes out-dated within only a few months, and it would be more advantageous to publish the methods as PDF files on the internet, as the most recent version would be available. NMKL therefore does not consider a method collection on CD-ROM to be the best alternative. |
Number
of subscribers: 436
Denmark:
116
Finland: 85
Iceland: 5
Norway:
132
Sweden: 81
Outside the Nordic: 17
A
subscription includes 6 methods annually.
Number
on mailing list:
736
receive
NMKL-newsletter only.
Sampling
– from science to practice,
seminar
at Lillehammer, August 2001
In
connection with the Annual Meeting, 2001, the Norwegian National committee
arranged a seminar on sampling. Sampling is an important aspect of ensuring a
reliable analytical result, and it is essential to have good, quality-assured
routines. NMKL is now working on a handbook in sampling, as an aid to
establishing good routines. In holding this seminar, the National Committee
hoped to focus attention on both sampling, and the handbook.
The
seminar was well attended, with 120 participants, from public food control and
administration, manufactures, research institutions, etc. All the Nordic
countries were represented. The topic is evidently both current and important
for many organisations.
The ten contributors illustrated the topic from different points of view. The sampling carried out by public authorities is often determined by national/international regulations, and the results of the tests are then the basis for risk analysis. We received an insight into the Danish food control authorities’ regulations with regard to sampling, a current topic for the other Nordic countries.
Sampling is based on scientific facts, but this must be adapted in practice, to give sampling plans that are possible to implement. Similarly, the analytical data from a single sample should be applicable to a whole batch, and provide the basis for sound decisions. Sampling plans should also take into account the type of testing to be performed, whether microbiological, chemical or sensory. It is necessary to distinguish between primary sampling, in the field or production/retailing site, and secondary sampling, in the laboratory, both of which contribute to the final result. The contributors gave an introduction in the scientific background, routines and equipment, and otherwise provided many useful hints.
Representatives from research institutions, food manufacturers and local public food control authorities presented their sampling routines, and discussed factors to be considered and routines to follow. The criteria for each sampling plan are determined by the aims of testing and the intended application of the data, and are based on scientific and statistical principles.
The seminar was concluded with a brief introduction in the use of NMKL’s Handbook in the field. Publication of the Handbook is expected in spring 2002.
Gudrun
Q. Rognerud
New
Chairwoman of the Norwegian National Committee
Gudrun Q. Rognerud is resigning as chairwoman of the Norwegian National Committee. She has been chairwoman since 1998/1999, and is at the same time retiring from her position as special advisor in the Norwegian Food Control Authority. Her structured and well-organized leadership reached a distinguished conclusion with NMKL’s 55th Annual Meeting and the seminar on sampling. We should like to thank her for an excellent co-operation. Dr. Tone Normann Asp, Norwegian School of Veterinary Science, will be taking over as chairwoman. The National Committee will remain in good hands, and we welcome Dr. Asp to a new period of co-operation.
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| Gudrun Q. Rognerud | Tone Normann Asp |
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