Review article: safe amounts of gluten for patients with wheat allergy or coeliac disease.

For both wheat allergy and coeliac disease the dietary avoidance of wheat and other gluten-containing cereals is the only effective treatment. Estimation of the maximum tolerated amount of gluten for susceptible individuals would support effective management of their disease. Literature was reviewed to evaluate whether an upper limit for gluten content in food, which would be safe for sufferers from both diseases, could be identified. When setting gluten limits for coeliac disease sufferers, the overall potential daily intake should be considered, while for wheat allergy limits should be based on single servings. For coeliac disease sufferers this limit should lie between 10 and 100 mg daily intake. For wheat allergy, lowest eliciting doses for children lie in the lower milligram range, while for adults they are most significantly higher. Gliadins (part of the gluten proteins) not only trigger coeliac disease, but are also major allergens in wheat allergy. Therefore, measurement of gliadins with validated enzyme-linked immunosorbent assay methods provides an appropriate marker for assessing gluten and/or wheat protein contents in food. Available data suggest that a maximum gluten content for 'gluten-free' foods could be set, which protects both wheat allergy sufferers and coeliac patients.

Analysis of steryl esters in cocoa butter by on-line liquid chromatography-gas chromatography.

On-line liquid chromatography-gas chromatography (LC-GC) has been applied to the analysis of steryl esters in cocoa butter. Separation of the steryl esters was achieved after on-line transfer to capillary GC. HPLC removes the large amount of triglycerides and pre-separates the components of interest, thus avoiding time-consuming sample preparation prior to GC analysis. The identities of the compounds were confirmed by GC-MS investigation of the collected HPLC fraction and by comparison of the mass spectra (chemical ionization using ammonia as ionization gas) to those of synthesized reference compounds. Using cholesteryl laurate as internal standard, steryl esters were quantified in commercial cocoa butter samples, the detection limit being 3 mg/kg and the quantification limit 10 mg/kg, respectively. Only slight differences in percentage distributions of steryl esters depending on the geographical origin of the material were observed. The patterns were shown to remain unchanged after deodorization. The method described might be a valuable tool for authenticity assessment of cocoa butter.

Determination of total taurine in pet foods by liquid chromatography of the dansyl derivative: collaborative study.

A liquid chromatographic (LC) method for the determination of total taurine in pet foods was evaluated in a collaborative study. Ten laboratories assayed 6 blind duplicate pairs of wet and dry pet foods. The taurine in the 6 sample pairs ranged from low (170 mg/kg) to high (2250 mg/kg) concentrations as is. Collaborators also assayed a sample of known taurine concentration for familiarization purposes. Samples were hydrolyzed to release bound taurine, which was subsequently converted to the dansyl derivative and quantitated by gradient-elution LC with fluorescence detection. Repeatability relative standard deviations, RSDr, ranged from 3.2 to 10.0%; reproducibility relative standard deviations, RSDR, ranged from 6.1 to 16.1%. The method has been adopted Official First Action status by AOAC INTERNATIONAL.

Determination of locust bean gum and guar gum by polymerase chain reaction and restriction fragment length polymorphism analysis.

A polymerase chain reaction (PCR) was developed to differentiate the thickening agents locust bean gum (LBG) and the cheaper guar gum in finished food products. Universal primers for amplification of the intergenic spacer region between trnL 3' (UAA) exon and trnF (GAA) gene in the chloroplast (cp) genome and subsequent restriction analysis were applied to differentiate guar gum and LBG. The presence of <5% (w/w) guar gum powder added to LBG powder was detectable. Based on data obtained from sequencing this intergenic spacer region, a second PCR method for the specific detection of guar gum DNA was also developed. This assay detected guar gum powder in LBG in amounts as low as 1% (w/w). Both methods successfully detected guar gum and/or LBG in ice cream stabilizers and in foodstuffs, such as dairy products, ice cream, dry seasoning mixes, a finished roasting sauce, and a fruit jelly product, but not in products with highly degraded DNA, such as tomato ketchup and sterilized chocolate cream. Both methods detected guar gum and LBG in ice cream and fresh cheese at levels <0.1%.

Criteria for identifying allergenic foods of public health importance.

The World Health Organisation and other food safety authorities recognise food allergy as a significant public health concern due to the high prevalence and potential severity of the condition and the impact it has on the quality of life and economy. A public health perspective focuses on risk management at the societal level rather than precautions taken by individuals. Allergen lists were originally drawn up on the basis of a combination of prevalence and severity information, but data to document inclusion were limited. Since then the number of allergenic foods for which reactions have been well documented has grown considerably. Yet, most of them are of limited significance to public health. To address food allergy issues from the point of view of risk management, an expert group appointed by the Food Allergy Task Force of the International Life Sciences Institute ILSI Europe reviewed the criteria. We propose a revised set of criteria together with a framework which can be used to help decide which allergenic foods are of sufficient public health importance to be included in allergen lists. Criteria include clinical issues (diagnosis, potency of allergen, severity of reactions), population elements (prevalence, exposure) and modulating factors (food processing). In the framework, data providing evidence for these criteria are weighted according to quality, using a ranking derived from evidence-based medicine. The advantage of this approach is that it makes explicit each of the considerations, thereby rendering the whole process more transparent for all stakeholders.

Maillard reaction products and lysinoalanine: urinary excretion and the effects on kidney function of preterm infants fed heat-processed milk formula.

Heat processing is essential for the preservation of milk-based infant formulas. Heating, however, induces a number of chemical changes during which lysine in the milk proteins reacts with reducing sugars to form Maillard reaction products (MRPs) and also reacts with the dehydroalanine resulting from cystine degradation to form lysinoalanine (LAL). Both products have been reported to induce histological changes in the straight portion of the proximal tubule in the rat kidney. This pilot study was made to investigate the urinary excretion by healthy preterm babies of MRPs and LAL contained in infant formula and to determine their influence on kidney function. Twelve healthy male preterm babies were first fed for 10 days with pooled human milk and then for 5 days with each of two experimental premature infant formulas in a cross-over design. The infant formulas were sterilized either by ultra-high temperature (UHT) treatment or by a conventional retort process to give products with low and high levels of MRPs and LAL, respectively. In total, some 15.6% of the initial lysine had been modified in the in-can-sterilized product, compared to 6.2% in the UHT product. Urinary excretion of MRP lactulosyllysine ranged from 1.3 to 3.9% of the ingested amount, whereas that of LAL ranged from 6.2 to 9.3%. The higher level of MRPs and LAL in the formulas compared to breast milk had no influence on creatinine clearance or electrolyte excretion. There was no evidence of tubular damage as determined by the urinary excretion of four kidney-derived enzymes. Feeding of formula, however, did result in a general increase in urinary microprotein levels.(ABSTRACT TRUNCATED AT 250 WORDS)