Development of an optimized ELISA and a sample preparation method for the detection of beta-lactoglobulin traces in baby foods.

Dairy products can induce allergic reactions even when present at very low levels, such as levels found in involuntary contamination during food manufacturing. beta-Lactoglobulin (betaLG) is the main allergen in cow's milk. The objective of this work was to develop a sensitive method for betaLG detection in baby foods through the optimization of an innovative sample preparation method. Three types of baby foods deliberately contaminated with dairy products or dairy desserts were sterilized to simulate the potential contamination occurring during manufacturing and then used as samples. Different sample preparation methods were compared. The best results were provided by an extraction solution containing beta-mercaptoethanol, guanidine hydrochloride, and a saline solution. An ELISA method was optimized for the detection of betaLG (LOD = 9.7 x 10(-13) M). The developed method allowed detection of even 1 part of dairy product in 100,000 parts of baby food for some of the analyzed foods.

Anion exchange liquid chromatography for the determination of nucleotides in baby and/or functional foods.

A sensitive, selective and solvent-free procedure is proposed for the rapid determination of monophosphate nucleotides (cytidine 5'-monophosphate, uridine 5'-monophosphate, adenosine 5'-monophosphate, and guanosine 5'-monophosphate) in baby foods. The method is based on the deproteinization of foods and direct analysis by anion exchange liquid chromatography (LC). Nucleotides were separated on an SAX anion exchange column with isocratic elution using 0.01 M dihydrogenphosphate buffer (pH 3.5) as mobile phase at a flow-rate of 1 mL min(-1) and detected by diode-array detection (DAD). The LC method rapidly separated the nucleotides (9 min) and was validated for linearity, detection and quantitation limits, selectivity, accuracy, and precision. The recoveries obtained for spiked samples were satisfactory for all the analytes. The proposed procedure allowed the only authorized nucleotides in infant formulas to be determined and was successfully applied to the analysis of different baby and/or functional food samples, including infant formulas, fermented milk, cereals, and purees.

A new sample preparation method compatible with capillary electrophoresis and laser-induced fluorescence for improving detection of low levels of beta-lactoglobulin in infant foods.

Beta-lactoglobulin (betaLG) is the main allergenic protein in cow's milk and can cause allergy even when present at very low concentration. The aim of this work is to develop an innovative sample preparation method fully compatible with capillary electrophoresis and laser-induced fluorescence detection for improving the sensitivity when analyzing betaLG. Different types of baby food were on purpose contaminated with diverse dairy desserts and submitted to thermal treatment to simulate potential contamination at production. Sample preparation prior to CE analysis was performed by the classical extraction method and by the innovative one, and the results were compared. Analysis was performed by capillary electrophoresis with laser-induced fluorescence detection. The innovative method permitted to detect contaminations as low as 1 part of yoghurt in 10,000 parts of baby food.