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Biomedical subjects

S L Hefle

Publications and source records attributed to S L Hefle.

27 records · Page 2Linked to original sources
PubMed1999

Impact of processing on food allergens.

In general, allergenic foods are resistant to processes commonly used in food manufacturing. Nearly all the causative proteins (allergens) retain their allergenicity after treatment by heat and/or proteolysis. Notable exceptions exist; for example, the allergenicity of many fresh fruits and vegetables is decreased or removed by relatively mild processes such as gentle heating or mashing. The use of proteolytic enzymes to remove allergenicity is successfully used in the production of hypoallergenic infant formulas, but this approach with other allergenic foods has resulted in only limited success. Processing effects can result in decreased or complete removal of allergenic qualities of a food, such as the removal of proteins in oilseed processing, which renders the oils hypoallergenic and safe for consumption by allergic individuals. This discussion will address the different allergenic foods and processes which can affect or decrease their allergenicity.

Allergens↗
PubMed1998

Anaphylaxis in a milk-allergic child following ingestion of lemon sorbet containing trace quantities of milk.

Although allergic persons can react to foods containing trace quantities of unlabeled or unintended food allergens, there are few data available on the quantities of these allergens required to evoke allergic symptoms. We report a milk-allergic 3-year-old boy who experienced throat itching, facial angioedema, and vomiting within 20 min of ingesting 4 to 6 oz (ca. 113.4 to 170.1 g) of lemon sorbet. Subsequent analysis of two sorbet samples provided by the parents and a third sample purchased locally by the investigators revealed trace quantities of milk allergens, whey protein (8.8 micrograms/ml), or lactose (200 ppm). The quantity of whey protein ingested was estimated to be 120 to 180 micrograms (equivalent to 23 to 24 microliters of milk). All three sorbet samples had been manufactured in the same plant within a 4-month period; the equipment used to produce and package the sorbet was also used to produce and package ice cream. No milk allergen or whey protein was detected in 38 other marketplace sorbet samples submitted by the manufacturer for testing. We concluded that trace quantities of whey proteins (< 200 micrograms) can elicit systemic reactions in exquisitely milk-allergic individuals. Such individuals should avoid eating frozen desserts prepared using equipment also used for producing or packaging ice cream, unless manufacturers can demonstrate unequivocally that their cleaning practices are sufficient to prevent milk contamination. Adequate tests are not currently available to food manufacturers but are under development.

Allergens↗
PubMed1997

An evaluation of the sensitivity of subjects with peanut allergy to very low doses of peanut protein: a randomized, double-blind, placebo-controlled food challenge study.

BACKGROUND: The minimum dose of food protein to which subjects with food allergy have reacted in double-blind, placebo-controlled food challenges is between 50 and 100 mg. However, subjects with peanut allergy often report severe reactions after minimal contact with peanuts, even through intact skin. OBJECTIVE: We sought to determine whether adults previously proven by challenge to be allergic to peanut react to very low doses of peanut protein. METHODS: We used a randomized, double-blind, placebo-controlled food challenge of 14 subjects allergic to peanuts with doses of peanut ranging from 10 microg to 50 mg, administered in the form of a commercially available peanut flour. RESULTS: One subject had a systemic reaction to 5 mg of peanut protein, and two subjects had mild objective reactions to 2 mg and 50 mg of peanut protein, respectively. Five subjects had mild subjective reactions (1 to 5 mg and 4 to 50 mg). All subjects with convincing objective reactions had short-lived subjective reactions to preceding doses, as low as 100 microg in two cases. Five subjects did not react to any dose up to 50 mg. CONCLUSION: Even in a group of well-characterized, highly sensitive subjects with peanut allergy, the threshold dose of peanut protein varies. As little as 100 microg of peanut protein provokes symptoms in some subjects with peanut allergy.

Adult↗
PubMed1996

Allergenic foods.

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Adolescent↗
PubMed1996

Food allergens.

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Allergens↗
PubMed1995

Comparison of commercial peanut skin test extracts.

BACKGROUND: Skin prick testing is a major tool for diagnosing food allergy. Food allergen extracts have not been standardized; this may lead to great variability in the predictive accuracy of skin prick tests. METHODS: Six commercial peanut skin test extracts were compared in vitro with RAST inhibition assays, ELISA, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting with sera from peanut-allergic adults and in vivo by skin prick testing. RESULTS: ELISA showed that the content of peanut allergens Ara h I and Ara h II in the extracts ranged from 0.0015 to 0.0236 and 0.0001 to 0.0164 mg Eq/ml, respectively. RAST inhibition studies showed that the extracts produced curves of similar slope, suggesting conservation of allergenic epitopes. SDS-PAGE revealed differences in protein profiles because roasted extracts generally possessed the same number and proportion of major protein bands but raw extracts varied more in both respects. SDS-PAGE and immunoblotting showed that two of the extracts contained major IgE-binding protein bands that did not appear in the others. One roasted extract gave little protein banding and consequently little IgE binding. CONCLUSIONS: Skin testing results showed no differences in the ability of the extracts to provoke a positive skin test response in peanut-sensitive subjects.

Arachis↗
PubMed1994

Adverse reaction to lupine-fortified pasta.

A 5-year-old girl with peanut sensitivity experienced urticaria and angioedema after ingesting a spaghetti-like pasta fortified with sweet lupine seed flour. The pasta was extracted and used in immunologic studies in patients with peanut sensitivity to determine whether such individuals are at similar risk. Results of skin prick tests with the lupine pasta extract were positive in five of seven subjects; these patients also reported a history of adverse reactions to green peas. In direct RAST studies IgE binding from pooled sera from patients with peanut sensitivity to the lupine pasta extract was 7 times that of a nonallergic control serum, and individual serum samples demonstrated binding from 1 to 6 times that of the negative control. Direct RAST studies of lupine seed flour with serum samples from patients with peanut allergy demonstrated IgE binding 1 to 11 times that of the negative control. Immunoblotting studies of electrophoretically separated pasta extract and lupine seed flour proteins showed IgE-binding protein bands at approximately 21 kd and in the range of 35 to 55 kd molecular weight. We conclude that some peanut-sensitive patients may be at risk for adverse reactions to lupine.

Adult↗