<p>A new European labeling directive (2003/89/EC) states that certain foods and products derived thereof must always be declared. Among the tree nuts specified is Macadamia nut (Macadamia spp.). During the last few years, cases of IgE-allergic reactions, even severe anaphylaxes, have been reported. Reliable methods for the detection of this nut are needed.</p><p>Protein from Macadamia nuts was isolated. Polyacrylamide gel electrophoresis in SDS revealed two main protein bands of about 20 and 50kDa. These protein bands were cut and extracted from the gel and rabbits were immunized with each protein.</p><p>Immunoblotting showed dominant reactivity with the respective antigens. The antisera were further tested for specificity in immunodiffusion and in rocket immunoelectrophoresis.</p><p>In addition, a specific DNA-method was developed, based on Real-Time PCR using Macadamia vicilin as target sequence. Two different primer pairs were tested. Specificity was tested against potentially related nuts. Optimisation of primer and probe concentrations was performed. The limit of detection was 2-4 pg DNA, corresponding to a macadamia nut concentration of 50 to 100 μg per g. In a background of soybean DNA, down to 0,01 % macadamia DNA could be detected.</p>

<p>Directive EC 2003/89/EC of the European Parliament and of the Council states that certain</p><p>ingredients and products derived there of known to cause allergen reactions must always be</p><p>declared. Furthermore labelling is mandatory irrespective of the amount included. The National</p><p>Food Administration therefore needs methods for monitoring the presence of allergens in food.</p><p>Methods already exist for most of the allergens on the EU-list, but an operational method for</p><p>celery (Apium graveolens) is missing.</p><p>A specific DNA-method was developed, based on TaqMan Real-Time PCR with the celery</p><p>mannitol dehydrogenase gene as target sequence. The analysis was started with homogenisation</p><p>of the sample followed by extraction of DNA. The Real-Time PCR method was shown to be</p><p>specific for celery, producing a 113 bp fragment with two celery varieties and negative results</p><p>with other closely selected species commonly present together with celery in food products (12</p><p>samples). The detection limit was 2-20 pg DNA, which corresponds to 1-7 haploid genome</p><p>copies. When evaluated with model samples of celery in meat, a detection limit of less than</p><p>0,01 % was determined. When used to analyse food products from the market, six out of seven</p><p>products declared to contain celery were correctly identified as positive.</p>

Directive EC 2003/89/EC of the European Parliament and of the Council states that certain ingredients and products derived there of known to cause allergen reactions must always be declared. Furthermore labelling is mandatory irrespective of the amount included. The National Food Administration therefore needs methods for monitoring the presence of allergens in food. Methods already exist for most of the allergens on the EU-list, but an operational method for celery (Apium graveolens) is missing. A specific DNA-method was developed, based on TaqMan Real-Time PCR with the celery mannitol dehydrogenase gene as target sequence. The analysis was started with homogenisation of the sample followed by extraction of DNA. The Real-Time PCR method was shown to be specific for celery, producing a 113 bp fragment with two celery varieties and negative results with other closely selected species commonly present together with celery in food products (12 samples). The detection limit was 2-20 pg DNA, which corresponds to 1-7 haploid genome copies. When evaluated with model samples of celery in meat, a detection limit of less than 0,01 % was determined. When used to analyse food products from the market, six out of seven products declared to contain celery were correctly identified as positive.

A new European labeling directive (2003/89/EC) states that certain foods and products derived thereof must always be declared. Among the tree nuts specified is Macadamia nut (Macadamia spp.). During the last few years, cases of IgE-allergic reactions, even severe anaphylaxes, have been reported. Reliable methods for the detection of this nut are needed. Protein from Macadamia nuts was isolated. Polyacrylamide gel electrophoresis in SDS revealed two main protein bands of about 20 and 50kDa. These protein bands were cut and extracted from the gel and rabbits were immunized with each protein. Immunoblotting showed dominant reactivity with the respective antigens. The antisera were further tested for specificity in immunodiffusion and in rocket immunoelectrophoresis. In addition, a specific DNA-method was developed, based on Real-Time PCR using Macadamia vicilin as target sequence. Two different primer pairs were tested. Specificity was tested against potentially related nuts. Optimisation of primer and probe concentrations was performed. The limit of detection was 2-4 pg DNA, corresponding to a macadamia nut concentration of 50 to 100 μg per g. In a background of soybean DNA, down to 0,01 % macadamia DNA could be detected.

No description available.