• Coagulase positive staphylococci. Enumeration in foods (NMKL Method No. 66, 3.ed. 1999)
• Aerobic microorganisms. Determination in foods
  (NMKL Method No. 86, 3.ed. 1999)
• Listeria monocytogenes. Detection in foods
  (NMKL Method No. 136, 2.ed. 1999)

Participating at a Nordic seminar on analysis of fats in foodstuffs, 9-10 September 1999? Click here!

NMKL's annual meeting in Kirkjubæjarklaustur, Iceland, 21-24 August 1999 Click here!

(NMKL Method No. 66, 3. ed. 1999)

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This method is used for enumeration of coagulase positive staphylococci in foods. The method is applicable to all foods. For fermented products where staphylococci have been used as starter cultures, a low number of coagulase positive staphylococci can be difficult to detect.

The genus Staphylococcus comprises Gram positive, facultative anaerobic, catalase positive spherical coccoid bacteria. Some species are coagulase positive. Among the coagulase positive staphylococci some strains produce staphylococcal enterotoxin (SE). Most enterotoxigenic strains belong to S. aureus, however, strains within S. intermedius and S. hyicus may also be enterotoxigenic. It should be pointed out that some strains belonging to the coagulase negative staphylococci may also produce SE. Staphylococci are widely distributed; the main reservoir is skin and mucosal surfaces of humans and warm-blooded animals.

Coagulase positive staphylococci in the food sample are enumerated by surface streaking of decimal dilutions of a specified quantity of the sample on the selective agar-medium Baird-Parker (BP) and/or on blood agar (BA). After incubation colonies with typical and atypical appearance are counted. A subset of these is tested for coagulase production.

NMKL give thanks to DVM, PhD Hilde Kruse, National Veterinary Institute, Oslo, Norway for the revision of this method.

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(NMKL Method No. 86, 3.ed. 1999)

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The method is suitable for determining the number of viable aerobic microorganisms in foods.

The method can be applied to all kinds of foods.

Aerobic microorganisms: Microorganisms, which grow under aerobic conditions when the test is carried out in accordance with the method described.

Aerobic colony count: The number of viable aerobic microorganisms per gram of food found providing the test is carried out in accordance with the method described.

Homogenization of the food in a mechanical blender with a dilution fluid. Preparation of decimal dilutions from the homogenate.Transfer of 1 ml aliquots of the diluted homogenate to empty Petri dishes where they are mixed with a non-selective agar medium. Incubation at 25^oC under aerobic conditions for 3 days. For analyses of products with a mesophile flora an incubation at 30^oC for 3 days may be used. Calculation of the number of viable aerobic microorganisms per gram of sample from the number of colonies per Petri dish.

NMKL give thanks to Allan Holmlund, SLU, Inst. for livsmedelshygien, Uppsala, Sweden for the revision of this method.

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(NMKL Method No. 136, 2.edition, 1999)

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The method is intended for qualitative and/or semi- quantitative determination of Listeria monocytogenes in all kinds of foods.

Listeria monocytogenes is a short, slender, Gram positive rod (20 h culture). It is catalase positive, shows tumbling, rotatory motility when microscoped and exhibits umbrella-shaped growth in motility tubes (when cultured at 20-25° C). The organism hydrolyses aesculin and exhibits a narrow ß-haemolytic zone when cultivated on blood agar. L. monocytogenes produces acid from rhamnose but not from xylose.

A two-stage enrichment procedure is used. Food samples are homogenised and incubated in a selective enrichment broth. After 24 hours a secondary enrichment broth with higher selectivity is used. Two alternative secondary enrichment broths are described, which are regarded to perform equally well. Isolation is performed on two selective agar media. Confirmation is achieved by determination of the morphological, physiological and biochemical properties of the isolate or by the use of a validated commercial available culture identification test.

NMKL give thanks to D.V.M., Ph.D.,Birgit Nørrung,

Ministry of Food, Agriculture and Fisheries, Søborg, Denmark, for revision of this method.

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A big advantage of being a member of NMKL is the opportunity to visit different, attractive places in the Nordic countries. This year the NMKL's national committee of Iceland is going to arrange the annual meeting, and they have invited the NMKL members to Kirkjubæjarklaustur on South Iceland.

Kirkjubæjarklaustur is the trade centre of a thriving farming community. It is sheltered by wooded cliffs, with a picturesque waterfall coming off the edge of the plateau behind Kirkjubæjarklaustur. To the front are views of the river and adjacent lava fields.

The Icelandic National Committee welcome the members of NMKL and observers from EK-Livs, AOAC International and IDF to the annual general meeting 21-24 August 1999.

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• Exchange of Practical Experience

• Practical experiences with different methods

9 - 10 September 1999

Analytical methods for the determination of fats in foodstuffs are constantly evolving. Therefore, a regular update of knowledge is of great importance. MATFORSK at Ås, Norway, in co-operation with the Royal Veterinary and Agricultural University of Denmark and Swedish Meats R&D, invites to a Nordic seminar titled: "Analysis of fats in foodstuffs - practical experience with different methods". The methods presented will focus on the use of very little or no organic solvents.

The seminar will give an overview of newer analytical methods used to quantify fats in foods. Among other topics, analytical principles such as supercritical fluid extraction (SFE), low solute nuclear magnetic resonance (NMR), near infrared reflection /transmission (NIR/NIT) and accelerated solvents extraction (ASE) will be discussed. The "Büchi fat determination system", one of the latest methods on the market, and approved by AOAC INTERNATIONAL, will also be presented. In co-operation with commercial suppliers, a workshop will be arranged to allow a close look at the practical side of the different methods and the equipment required.

The seminar is aimed at professionals in the food and service industries, analytical laboratories, governmental food control authorities, research, educational and commercial institutions, and suppliers of analytical equipment.

The analytical principles presented are applicable to a wide range of disciplines not limited to the food industry. Thus, this seminar will be useful to professionals in other analytical capacities.

The seminar is arranged at the Quality Airport Hotel, Gardermoen, September 9 - 10, 1999
Close date for entries: 15. June to Matforsk
Price: NOK: 3500
Overnight stay at the hotel: NOK 1295 (full board)
Contact persons at Matforsk:
Senior Engineer Frank Lundby
Secretary Ragnhild Norrang, tel: +47 64 97 01 00, fax: +47 64 97 03 33
e-mail: ragnhild.norrang@matforsk.no

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