The secretariat of NMKL wishes you all a lovely summer!!

New NMKL Methods:
No. 137, 2nd Ed., 2002: Bacterial count. Determination by direct epifluorescent filter technique (DEFT) in raw minced meat.
No. 171, 2002: Halophilic and osmophilic microbes (‘pink’ and ‘dun’). Determination in salted fish products.
No. 172, 2002: Ergosterol. Deter­mination by HPLC in cereals.

New NMKL Procedures:
NMKL Procedure No. 12, 2002: Guide on Sampling for Analysis of Foods.
NMKL Procedure No. 8, 2nd. Ed., 2002: Measurement of uncertainty in microbiological examination of foods.
NMKL Procedure No. 10 (Control of Microbiological Media) available in English

Seminar: How safe is it to eat Nordic fish? 

Courses in the Evaluation of Results from Certified Reference Materials (CRMs)

New secretary of the Norwegian National Committee of NMKL

News from NordVal

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NMKL is arranging

Courses in the Evaluation of Results from Certified Reference Materials (CRMs)

The courses are based on NMKL procedure no. 9, 2001: Evaluation of results derived from the analysis of certified reference materials.

Set aside the following dates for courses in CRM:

19th November 2002:   National Veterinary Institute, Oslo, Norway
21st November 2002:    Helsinki, Finland*
25th November 2002:   National Food Administration, Uppsala, Sweden
26th November  2002:  Copenhagen, Denmark*
27th November 2002:  Reykavik, Island*

*exact location to be determined.

Course Administrator: Lars Jorhem, National Food Administration, Sweden. Jorhem has been the administrator and author of the NMKL procedure no 9, and is recognised in both the Nordic countries and internationally for his work in procedures for the evaluation and use of certified reference materials.

Preliminary program:

Each section will include several practical examples for calculation.

Registration: The numbers participating in each course are limited, so it pays to register in good time. Registration should be sent to NMKL’s general secretariat by e-mail: nmkl@vetinst.no within 10^th November 2002.

Course fee: NOK 1000,- (incl. lunch) -  information on method of payment will be given at the time of registration. 

Further information on the courses will be given on NMKL’s home page: www.nmkl.org

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NMKL Method No. 137, 2nd Ed., 2002:

BACTERIAL COUNT. Determination by direct epifluorescent filter techn-ique (DEFT) in raw minced meat.

Laboratory Manager, Flemming Boisen, Danish Veterinary and Food Administration, Region of Fyn, Denmark has revised the edition from 1990. Boisen has also previously administered the collaborative study of the method.

The principal changes in the newer edition include a more detailed description for the preparation of various reagents, together with an explanation of the significance of the colours when the organisms are stained. In addition, the pretreatment of the sample has been slightly simplified.

The principle of the method is the same as in the previous edition. A known test volume is pretreated with an enzyme and a surfactant. The microorganisms in the resulting solution are concentrated by passing through a membrane filter. The microorganisms are then stained using a dye that gives orange and orange-yellow fluorescence when illuminated with blue light.

This NMKL method was studied on raw minced meat, with satisfactory results. Twelve laboratories participated.

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NMKL Method No. 171, 2002:

HALOPHILIC AND OSMOPHILIC MICROBES (‘pink’ and ‘dun’). Determination in salted fish products.

Grete Lorentzen, Guro Pedersen and Olaug Taran Skjerdal, Fiskeri-forskningen, Tromsø, Norway have elaborated this NMKL method.

Pink and dun require 15 and 7.5% NaCl respectively for growth and they are lysed at higher salt concentrations. In addition, they have stringent nutritional requirements and cannot grow on standard agar growth medium, which is the reason for NMKL elaborating method no. 171.

Fully-salted fish products contain approx. 20% salt, and can be preserved for several months if kept dry at 4ºC. At higher temperatures, they are destroyed by halophilic and osmophilic microbes, known as  "pink" and "dun". These organisms only affect high-salt products. 

Pink is a traditional term for visible growth of extremely halophilic bacteria in fully-salted fish products. The bacteria belong to the family Halobacteriaceae and are Gram negative. The majority are non-motile and obligate aerobes. The colonies occur in varying shades of red.

Dun is the traditional term for the occurrence of brown colonies (1-2 mm in diameter) in salted fish. Their brown colour changes with salt content. Dun is a single-celled fungus Wallemia sebi, an obligate aerobe.

Pink and dun can be demonstrated by seeding on the appropriate agar media. Samples for pink are incubated in the light at 37°C for 2-3 weeks, while samples for dun are incubated at 20-24°C (room temperature) for 2 weeks or more.

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NMKL Method No. 172, 2002:

ERGOSTEROL. Determina-tion by HPLC in cereals.

Anders Staffas, National Food Administration, Sweden, has elaborated and arranged the collaborative study of this NMKL method.  

Existing official guidelines for mould in cereals and cereal products are based on microbiological analytical methods, which can take up to a week and the results of which (CFU/g) give little information on the degree of mould growth. The microbiological methods are useful in demonstrating which mould species are growing, but there is a need for more rapid methods measuring the total biomass of fungal moulds and which can function as a measure of hygienic quality. Ergosterol is such a marker. Ergosterol is a lipid occurring in fungi (moulds and yeasts), both in the free form and esterified with fatty acids.

The principle for the method is:
- hydrolysis (releasing ergosterol)
- extraction with hexane on a silica-based column. 
- analysis using normal phase HPLC with UV detection.

The method has been tested in a NMKL collaborative study arranged by Anders Staffas, with 8 participating laboratories. One laboratory had to be excluded as they had used reverse phase chromatography instead of normal phase. The study was carried out on oats, wheat, barley and wheat flour. The results of the study were satisfactory.

NMKL would like to thank Flemming Boisen, Grete Lorentzen, Guro Pedersen, Olaug Taran Skjerdal and Anders Staffas, and their institutes, for their considerable work in the method elaborating and arrangement of the collaborative studies.

NMKL would also like to thank all the laboratories that have participated in the studies and the contact persons for their valuable comments and input.

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New procedure: NMKL Procedure No. 12, 2002:

GUIDE ON SAMPLING FOR ANALYSIS OF FOODS

Considerable effort and resources are expended on the analysis of foodstuffs. However, frequently, too few units are selected, or they are selected in such a manner that they are not representative of the lot under scrutiny. The consequences may be unreliable results and wasted time and effort, which may ultimately lead to wrong administrative decisions. Wrong results will also be obtained if test samples are incorrectly labelled, inappropriately stored or pre-treated in a manner not conforming to rules or regulations. The sample size should be appropriate to the purpose - either more or less samples would be a waste of money. A working group established by the Nordic Committee on Food Analysis elaborated this procedure within the framework of a project under the Nordic Council of Ministers. The following persons were members of the working group: Denmark: Erling Pedersen, Danish Veterinary and Food Administration Finland: Pirjo-Liisa Penttilä, National Food Agency Iceland:  Jónina Stefánsdóttir, Environment and Food Agency of Iceland Norway: Per Lea, MATFORSK - Norwegian Food Research Institute, Astrid Nordbotten and Hilde Skaar Norli, National Veterinary Institute Sweden: Per Norberg, National Food Administration NMKL Secretary General, Hilde Skaar Norli has officiated as project leader.

The procedure describes, amongst other matters, which aspect should be considered when designing projects and sampling plans. Various sampling techniques, equipment and some given sampling plans are further described, together with the keeping, storage, reduction and pre-treatment of samples.

The NMKL procedure is intended for sampling procedures designers, sampling and laboratory personnel and stakeholders - in essence: everyone concerned with the analysis of food and decision-making based on such analyses.

Norwegian and English versions of the procedure are published and may be ordered from the NMKL’s General Secretariat. The NMKL Procedure No. 12 will also be translated into Finnish.

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New edition of the NMKL Procedure No. 8:

MEASUREMENT OF UNCERTAINTY IN MICROBIOLOGICAL EXAMINATION OF FOODS  

The estimation and expression of measurement uncertainty when reporting quantitative results have become important in connection with quality assurance and accreditation of analysis at microbiological food laboratories. This NMKL procedure describes some simple procedures and techniques, which may be used for this purpose.

This procedure is a revised version of NMKL Procedure No. 8 (1999). The revision has been carried out by Professor Eystein Skjerve, the Norwegian School of Veterinary Science. The author especially appreciated comments and suggestions put forward in connection with the NMKL courses in measurement uncertainty, together with input from experts in NMKL’s National Committees. Ones again, our thanks to Prof. Skjerve for his pioneering work.

The NMKL Procedure No. 8, 2nd edition, includes new material, several examples and corrections and updates. A simple spreadsheet (Excel), illustrating the use of the described techniques, has been prepared in connection with this report. The spreadsheet can be downloaded free of charge from NMKL’s web page: http://www.nmkl.org. The NMKL Procedure can be ordered form NMKL’s General Secretariat. The revised edition is so far only available in Norwegian, but will also be translated into English.

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Call to mind the seminar:

HOW SAFE IS IT TO EAT NORDIC FISH?

Friday August 23, 2002 at Hotel Arkipelag, Mariehamn, Åland

The seminar will provide a forum for nutritionists, food control authorities and laboratories, as well as for research personnel within food science. It is open to all participants from the Nordic and the Baltic countries.

Themes for the seminar are:
- The nutritional quality of fish
- Known harmful effects associated with eating fish
- EU legislation on fish and the official control of fish
- Toxic substances in the Baltic Sea
- Dioxins in Baltic fish

The program is available at NMKL’s homepage under course/seminar.

Language: English.

Registration Fee: 150 € (incl. abstracts, lunch as well as morning and afternoon coffee).

Register to Christina Bäckman on e-mail: Christina.Backman@eela.fi

Deadline: Immediately. 

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The NMKL Procedure No. 10, 2001:

Control of Microbiological Media,

which was presented in the NMKL Newsletter No. 48/01 is soon also available in English.

Click here to read more about the procedure.

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NMKL would like to warmly welcome Dag Grønningen, National Veterinary Institute, as the new secretary of the Norwegian National Committee of NMKL. We look forward to the cooperation. 

NMKL would also like to thank Astrid Nordbotten for her excellent cooperation over many years.

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NEWS FROM NORDVAL

In 2002 NordVal has revised its "Terms of Reference". The validation programme now includes the validation of alternative microbiological methods for foods, water, feed of animal and vegetable origin, animal faeces and food environmental samples. The validation can include the complete analytical procedure, but also be limited to a single analytical step.

In May 2002, the first two NordVal validations of methods covering just one analytical step were completed:

- the AccuProbe Listeria Monocytogenes Culture Identification Test for the confirmation of presumptive Listeria monocytogenes harvested from solid media and

- the AccuProbe Campylobacter Culture Identification Test for the confirmation of Campylobacter (jejuni, coli and laridis) harvested from solid media.

NordVal validations of single analytical steps are considered to become of increasing interest also for NMKL methods. Already now in NMKL method no 136: "Listeria monocytogenes. Detection in Foods" a paragraph is included, which indicate that validated commercial test kits can be used for confirmation of presumptive Listeria monocytogenes.

 This spring NordVal has completed extended validation of the two following test kits:

- the Transia Plate Salmonella Gold. In June 2001 this kit was granted NordVal validation for meat and meat products and dairy products. In April 2002 the validation was extended to cover all food matrices.

- 3M Petrifilm Enterobacteriaceae Count Plate for the enumeration of enterobacteriaceae in all foods.

For further information on approved methods and validation of alternative methods, see NordVal’s web pages at www.nmkl.org and click on NordVal.

Sven Qvist
Chairman of NordVal

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Copyright © NMKL.  Med enerett.
Revidert: 28 september 2005 .