The major allergen parvalbumin was purified from cod muscle tissues, and polyclonal antibodies we... more The major allergen parvalbumin was purified from cod muscle tissues, and polyclonal antibodies were raised towards it. The antibodies were tested for specificity and an enzyme-linked immunosorbent assay (ELISA) was developed using these antibodies. The ELISA was applied to measure parvalbumin in cod skin, the starting material for fish gelatin made from deep sea, wild fish. The ELISA was sufficiently sensitive (LLOQ = 0.8 ng ml(-1) in extracts, corresponding to 0.02 µg of parvalbumin per g of tissue), and did not cross-react with common food constituents. Fish gelatin, wine and beer, matrices for the potential use of this ELISA, did not cause disturbance of the assay performance. The data show that the parvalbumin content in cod muscle tissue is 6.25 mg g(-1), while the skins contained considerably less, 0.4 mg g(-1). Washing of the skins, a common industrial procedure during the manufacturing of fish gelatin, reduced the level of parvalbumin about 1000-fold to 0.5 µg g(-1), or 0.5 ppm. From 95 commercial lots of fish gelatin it is shown that 73 are below 0.02 µg g(-1) parvalbumin. From the other 22 lots, the one with the highest concentration contained 0.15 µg g(-1) of parvalbumin. These levels are generally assumed to be safe for fish-allergic individuals.
A portable, handheld gluten detection device, the Nima sensor, is now available for consumers wis... more A portable, handheld gluten detection device, the Nima sensor, is now available for consumers wishing to determine if gluten is present in food. By U.S. regulation, gluten-free foods should contain <20 ppm of gluten. Thirteen gluten-free foods (muffins, three different types of bread, three different types of pasta, puffed corn snack, ice cream, meatballs, vinegar and oil salad dressing, oatmeal, and dark chocolate) were prepared; each food was spiked on a weight to weight basis with gluten levels of 0, 5, 10, 20, 30, 40, and 100 ppm before processing or preparation. Unprocessed and processed foods were tested with the handheld gluten sensor and by two gluten-specific enzyme-linked immunosorbent assays (ELISAs) on the basis of the R5 and G12 monoclonal antibodies, respectively. The portable gluten detection device detected gluten in all food types at the 30-ppm addition level, failing to detect gluten in only 5 (6.4%) of 78 subsamples. At the 20-ppm addition level, the portable g...
Sulfiting agents, which have been used as salad fresheners to prevent the enzymatic browning of r... more Sulfiting agents, which have been used as salad fresheners to prevent the enzymatic browning of restaurant salads, may pose a hazard to sulfite-sensitive asthmatics. Chopped lettuce treated with a commercial salad freshener at the recommended level of 1 tablespoon per gallon (ca. 5.3 g/L) of dip solution can contain as much as 963 mg/kg (ppm) total SO2 equivalents. Most of the sulfite in chopped lettuce is free SO2. If commercial salad fresheners are abused by using levels in excess of 1 tablespoon per gallon, progressively higher levels of residual sulfite are retained on the lettuce. Cole slaw prepared according to a typical commercial formulation contained 350 mg/kg total SO2. A survey of lettuce salads, cole slaw and potato salads from 25 local and national chain restaurants and delicatessens in Madison, Wisconsin, showed sulfite residue levels to be well below those of a treated salad, indicating a lack of sulfite use.
The Journal of allergy and clinical immunology, Jan 24, 2017
Eliciting doses (ED) of allergenic foods can be defined by the distribution of threshold doses fo... more Eliciting doses (ED) of allergenic foods can be defined by the distribution of threshold doses for individuals within a specific population. ED05 is the dose that elicits a reaction in 5% of allergic subjects. The predicted ED05 for peanut (PN) is 1.5 mg of peanut protein (6 mg whole peanut). We sought to validate the predicted peanut ED05 (1.5 mg) with a novel single dose challenge. Consecutive eligible peanut allergic children in 3 centres were prospectively invited to participate, irrespective of previous reaction severity. Predetermined criteria for objective reactions were used to identify ED05 single dose reactors. 518 children (mean age 6.8 years) were eligible. No significant demographic or clinical differences were identified between 381(74%) participants and 137 (26%) non-participants or between subjects recruited at each centre. 378 children (206 male) completed the study. Almost half the group reported ignoring precautionary allergen labelling. 245 (65%) experienced no r...
RationaleSoybean-allergic individuals may be instructed by clinicians to avoid all foods derived ... more RationaleSoybean-allergic individuals may be instructed by clinicians to avoid all foods derived from soybeans including soybean oil. However, highly refined soybean oil contains extremely low levels of protein. Previous work suggested that soybean oil was not allergenic, but the number of subjects challenged was small and the protein content of the oil was unknown. These deficiencies are rectified in this
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, Jan 24, 2016
Four different market classes of peanut (Runner, Virginia Spanish, and Valencia) are commonly con... more Four different market classes of peanut (Runner, Virginia Spanish, and Valencia) are commonly consumed in Western countries, but for some consumers peanuts are a main cause of food-induced anaphylaxis. Limited information is available on the comparative allergenicity of these distinct market classes. The aim of this study was to compare allergenicity attributes of different peanut cultivars. The protein content and protein profiles were highly comparable for all tested cultivars. All cultivar samples contained the major allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6, as assessed by SDS-PAGE and RP-HPLC, although some minor differences in major allergen content were found between samples. All samples were reactive in commercial ELISAs for detection and quantification of peanut protein.. IgE-binding potency differed between samples with a maximum factor of 2, indicating a highly comparable allergenicity. Based on our observations, we conclude that peanuts from the main market types c...
The major allergen parvalbumin was purified from cod muscle tissues, and polyclonal antibodies we... more The major allergen parvalbumin was purified from cod muscle tissues, and polyclonal antibodies were raised towards it. The antibodies were tested for specificity and an enzyme-linked immunosorbent assay (ELISA) was developed using these antibodies. The ELISA was applied to measure parvalbumin in cod skin, the starting material for fish gelatin made from deep sea, wild fish. The ELISA was sufficiently sensitive (LLOQ = 0.8 ng ml(-1) in extracts, corresponding to 0.02 µg of parvalbumin per g of tissue), and did not cross-react with common food constituents. Fish gelatin, wine and beer, matrices for the potential use of this ELISA, did not cause disturbance of the assay performance. The data show that the parvalbumin content in cod muscle tissue is 6.25 mg g(-1), while the skins contained considerably less, 0.4 mg g(-1). Washing of the skins, a common industrial procedure during the manufacturing of fish gelatin, reduced the level of parvalbumin about 1000-fold to 0.5 µg g(-1), or 0.5 ppm. From 95 commercial lots of fish gelatin it is shown that 73 are below 0.02 µg g(-1) parvalbumin. From the other 22 lots, the one with the highest concentration contained 0.15 µg g(-1) of parvalbumin. These levels are generally assumed to be safe for fish-allergic individuals.
A portable, handheld gluten detection device, the Nima sensor, is now available for consumers wis... more A portable, handheld gluten detection device, the Nima sensor, is now available for consumers wishing to determine if gluten is present in food. By U.S. regulation, gluten-free foods should contain <20 ppm of gluten. Thirteen gluten-free foods (muffins, three different types of bread, three different types of pasta, puffed corn snack, ice cream, meatballs, vinegar and oil salad dressing, oatmeal, and dark chocolate) were prepared; each food was spiked on a weight to weight basis with gluten levels of 0, 5, 10, 20, 30, 40, and 100 ppm before processing or preparation. Unprocessed and processed foods were tested with the handheld gluten sensor and by two gluten-specific enzyme-linked immunosorbent assays (ELISAs) on the basis of the R5 and G12 monoclonal antibodies, respectively. The portable gluten detection device detected gluten in all food types at the 30-ppm addition level, failing to detect gluten in only 5 (6.4%) of 78 subsamples. At the 20-ppm addition level, the portable g...
Sulfiting agents, which have been used as salad fresheners to prevent the enzymatic browning of r... more Sulfiting agents, which have been used as salad fresheners to prevent the enzymatic browning of restaurant salads, may pose a hazard to sulfite-sensitive asthmatics. Chopped lettuce treated with a commercial salad freshener at the recommended level of 1 tablespoon per gallon (ca. 5.3 g/L) of dip solution can contain as much as 963 mg/kg (ppm) total SO2 equivalents. Most of the sulfite in chopped lettuce is free SO2. If commercial salad fresheners are abused by using levels in excess of 1 tablespoon per gallon, progressively higher levels of residual sulfite are retained on the lettuce. Cole slaw prepared according to a typical commercial formulation contained 350 mg/kg total SO2. A survey of lettuce salads, cole slaw and potato salads from 25 local and national chain restaurants and delicatessens in Madison, Wisconsin, showed sulfite residue levels to be well below those of a treated salad, indicating a lack of sulfite use.
The Journal of allergy and clinical immunology, Jan 24, 2017
Eliciting doses (ED) of allergenic foods can be defined by the distribution of threshold doses fo... more Eliciting doses (ED) of allergenic foods can be defined by the distribution of threshold doses for individuals within a specific population. ED05 is the dose that elicits a reaction in 5% of allergic subjects. The predicted ED05 for peanut (PN) is 1.5 mg of peanut protein (6 mg whole peanut). We sought to validate the predicted peanut ED05 (1.5 mg) with a novel single dose challenge. Consecutive eligible peanut allergic children in 3 centres were prospectively invited to participate, irrespective of previous reaction severity. Predetermined criteria for objective reactions were used to identify ED05 single dose reactors. 518 children (mean age 6.8 years) were eligible. No significant demographic or clinical differences were identified between 381(74%) participants and 137 (26%) non-participants or between subjects recruited at each centre. 378 children (206 male) completed the study. Almost half the group reported ignoring precautionary allergen labelling. 245 (65%) experienced no r...
RationaleSoybean-allergic individuals may be instructed by clinicians to avoid all foods derived ... more RationaleSoybean-allergic individuals may be instructed by clinicians to avoid all foods derived from soybeans including soybean oil. However, highly refined soybean oil contains extremely low levels of protein. Previous work suggested that soybean oil was not allergenic, but the number of subjects challenged was small and the protein content of the oil was unknown. These deficiencies are rectified in this
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, Jan 24, 2016
Four different market classes of peanut (Runner, Virginia Spanish, and Valencia) are commonly con... more Four different market classes of peanut (Runner, Virginia Spanish, and Valencia) are commonly consumed in Western countries, but for some consumers peanuts are a main cause of food-induced anaphylaxis. Limited information is available on the comparative allergenicity of these distinct market classes. The aim of this study was to compare allergenicity attributes of different peanut cultivars. The protein content and protein profiles were highly comparable for all tested cultivars. All cultivar samples contained the major allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6, as assessed by SDS-PAGE and RP-HPLC, although some minor differences in major allergen content were found between samples. All samples were reactive in commercial ELISAs for detection and quantification of peanut protein.. IgE-binding potency differed between samples with a maximum factor of 2, indicating a highly comparable allergenicity. Based on our observations, we conclude that peanuts from the main market types c...
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Papers by Julie Nordlee