Search

This study aimed to investigate changes in macronutrients, total bacterial count, and serum proteome of human milk (HM) under different frozen storage (-18°C and -60°C, 60 d and 180 d) by using IBT Labeling proteomics techniques and ELISA kit. The results indicated that total protein concentrations and total aerobic bacterial counts were significantly decreased at -18°C, while no difference at -60°C. A total of 1617 proteins were identified and quantified, and 173 proteins were significantly different. The -18°C storage had much higher influence on HM serum protein profiles than that of -60°C. Increased milk fat globule membrane (MFGM) proteins at -18°C are highly related to the damage of MFGM and transfer of MFGM proteins. The reduction of bioactive proteins is probably related to the ice-induced denaturation. In conclusion, fast cooling and ultra-low constant temperature are more suitable for the cryopreservation of human milk.

Gluten from wheat, rye, and barley can trigger IgE-mediated allergy or Celiac disease in sensitive individuals. Gluten-free labeled foods are available as a safe alternative. Immunoassays such as the enzyme-linked immunosorbent assay (ELISA) are commonly used to quantify gluten in foods. However, various non-assay related factors can affect gluten quantitation. The effect of gluten-containing grain cultivars, thermal processing, and enzymatic hydrolysis on gluten quantitation by various ELISA kits was evaluated. The ELISA kits exhibited variations in gluten quantitation depending on the gluten-containing grain and their cultivars. Acceptable gluten recoveries were obtained in 200mg/kg wheat, rye, and barley-spiked corn flour thermally processed at various conditions. However, depending on the enzyme, gluten grain source, and ELISA kit used, measured gluten content was significantly reduced in corn flour spiked with 200mg/kg hydrolyzed wheat, rye, and barley flour. Thus, the gluten grain source and processing conditions should be considered for accurate gluten analysis.

Many gluten-free (GF) food choices are now available in supermarkets. However, the unintentional presence of gluten in these foods poses a serious health risk to wheat-allergic and celiac patients. Different GF labelled foods (275) and non-GF labelled foods, without wheat/rye/barley on the ingredient label (186), were analysed for gluten content by two different enzyme linked immunosorbent assay (ELISA) kits. Considering the gluten threshold of 20 ppm, GF labelled foods had 98.9% GF labelling compliance with 1.1% (3 out of 275) of foods being mislabelled/misbranded. Among the non-GF labelled foods, 19.4% (36 out of 186) of foods had >20 ppm of gluten, as measured by at least one ELISA kit, of which 19 foods had >100 ppm of gluten. The presence of oats in non-GF labelled foods was strongly correlated with a positive ELISA result. Gluten was also found in a significant number of foods with gluten/wheat-related advisory warnings.

Recently some cases described allergic reactions to undeclared lysozyme present in foods. In order to protect the allergic consumer, a better control is needed based on reliable and specific detection and quantification methods. The two currently used methods, a commercially available enzyme-linked immunosorbent assay (ELISA) for egg white allergens and a liquid chromatographic method, were compared. Despite the technical specifications of the ELISA kit, ensuring quantitative analysis of lysozyme in absence of other egg white proteins, no reliable quantitative and even qualitative data could be obtained which contrasted with the capabilities of the instrumental technique. A more elaborated evaluation of the methods on spiked samples identified the causes of the observed discrepancies. It was shown that next to a poor sensitivity of the ELISA kit also an insufficient lysozyme extraction and a co-extraction of interfering substances were the causes of the anomalies observed during application of the immunochemical method.

The gliadin contents of twenty-eight commercially available beers spanning the range of grist material and alcohol level were determined using a competitive enzyme immunoassay (RIDASCREEN competitive ELISA kit). The gliadin levels ranged from