Development of a sandwich enzyme-linked immunosorbent kit for reliable detection of milk allergens in processed food.

The inclusion of undeclared cow's milk proteins may cause health complications to milk-allergic consumers and is one of the leading cause of food recall in many countries all over the world. Therefore, to keep control on such incidences in processed products, we established a milk sandwich ELISA test kit by incorporating two polyclonal antibodies against milk proteins obtained from different species. Its analytical effectiveness in terms of sensitivity, specificity, accuracy, trueness, and precision were all analyzed. The limit of detection (LOD) of the test kit was 0.011 ppm, with high specificity for milk protein residues. The test kit was highly specific, apart from considerable cross-reactivity with goat milk and minor cross-reactivity with donkey and horse milk. The coefficient of variation of the test kit for intra-assay ranged from 4.02% to 14.62% and inter-assay ranged from 6.05% to 15.08% respectively. The sandwich ELISA was highly specific in detecting commercial food products. In a limited retail survey, 5/6 of the milk proteins declared on the ingredient labels tested positive for milk proteins. The study offers effective technical support for the sensitive detection of milk products both for food manufacturers and regulatory authorities.

A sensitive sandwich enzyme-linked immunosorbent assay (sELISA) targeted multiple wheat protein fractions for the detection of several cereal grains in processed foods.

Wheat allergy has become a global public health and food safety concern; however, there is no accessible cure for wheat allergy. The complete exclusion of wheat-containing foods and environmental exposure is the most efficient allergy management to avoid the adverse reactions, which can be severe and occasionally life threatening. Therefore, the assay for accurate detection of wheat residues is demanded urgently for appropriate labeling guidelines and consumer safety. Thus, a sandwich enzyme-linked immunosorbent assay (sELISA) targeting multiple wheat protein fractions was fabricated in the present study. The results showed that the limit of detection (LOD) and limit of quantitation (LOQ) of the constructed sELISA were 0.25 and 0.5 µg/g with high specificity for wheat. No cross-reactivity was observed in 32 foods or food ingredients tested, except barley and rye. The developed sELISA can also discriminate against many commercial foods containing declared or undeclared wheat residues except for Chinese yellow wine. Furthermore, high heat also can obtain a higher level of proteins extracted with corresponding enhanced detectability up to 100°C from heated samples and 160 °C in baked samples. PRACTICAL APPLICATION: Wheat is the most common food ingredient and wildly applied in various processed foods. However, wheat can cause severe and life-threatening symptoms in some allergic patients and must be labeled and tested accurately to protect those with a wheat allergy. Developing a new test assay can serve as a powerful tool for food manufacturers and regulatory agencies to accurately quantify wheat residues in processed foods and ensure their absence due to unintended contamination.

A review on food processing and preparation methods for altering fish allergenicity.

People eat many varieties of food to satiate their hunger. Among them, a few numbers of food cause overreaction of the body's immune system, and fish holds a permanent position on that list. Processing methods, including one treatment or a combination, can have different effects on the allergenic potential of food proteins. An important point to note, however, is that not all of these methods can eliminate the potential for protein allergy. Thus, it is essential to understand the risk involved with the consumption of processed fish and its derivatives. Fish could be prepared in various ways before come to the dining plate. It has shown some of these methods can effectively manipulate the allergenicity owing to the alterations occurred in the protein conformation. This article provides an overview of the impact of fish processing methods (thermal and non-thermal) on the allergenic potential of fish along with possible causative structural modification provokes allergen stability. The article begins with current trends related to fish consumption, proceeds with the prevalence and underlying mechanism of fish allergy. Properties of clinically relevant fish proteins, projected IgE epitopes of PV, cross-reactivity of fish allergens are also addressed in this context to understand and compare the behavioral patterns of PV profiles of different species on processing methods.

Development of a sensitive sandwich-ELISA assay for reliable detection of fish residues in foods.

A new sandwich-type Enzyme-Linked Immunosorbent Assay (ELISA) method was developed based on goat IgG as capturing antibody and rabbit IgG as detecting antibody targeting soluble antigenic fish proteins in foods as detection targets. The assay has provided a relatively lower limit of quantitation (LoQ) for fish proteins with LoQ 0.5 ng/ml and appears highly sensitive. The analysis of 24 different substances, both raw and boiled, revealed no cross-reactivity above the cut-off point of the limit of quantitation. Recoveries of the SB spiked food matrixes were in the range of 83-131%. Assay precision testing proved that repeatability (<5%) and reproducibility (<11%) had an acceptable level of variation. The sandwich ELISA was capable of detecting all tested commercially important fish. As a potential analytical tool, the newly developed immunoenzymatic method is suitable for detecting undeclared fish residues in real food samples available in the market, thereby will help to reduce the incidents of fish allergies.

Whey allergens: Influence of nonthermal processing treatments and their detection methods.

Whey and its components are recognized as value-added ingredients in infant formulas, beverages, sports nutritious foods, and other food products. Whey offers opportunities for the food industrial sector to develop functional foods with potential health benefits due to its unique physiological and functional attributes. Despite all the above importance, the consumption of whey protein (WP) can trigger hypersensitive reactions and is a constant threat for sensitive individuals. Although avoiding such food products is the most successful approach, there is still a chance of incorrect labeling and cross-contamination during food processing. As whey allergens in food products are cross-reactive, the phenomenon of homologous milk proteins of various species may escalate to a more serious problem. In this review, nonthermal processing technologies used to prevent and eliminate WP allergies are presented and discussed in detail. These processing technologies can either enhance or mitigate the impact of potential allergenicity. Therefore, the development of highly precise analytical technologies to detect and quantify the existence of whey allergens is of considerable importance. The present review is an attempt to cover all the updated approaches used for the detection of whey allergens in processed food products. Immunological and DNA-based assays are generally used for detecting allergenic proteins in processed food products. In addition, mass spectrometry is also employed as a preliminary technique for detection. We also highlighted the latest improvements in allergen detection toward biosensing strategies particularly immunosensors and aptasensors.

Extraction of total wheat (Triticum aestivum) protein fractions and cross-reactivity of wheat allergens with other cereals.

A one-step mild extraction of total wheat protein fractions was developed in this study, and the allergic cross-reactivity among dietary cereals were assessed by SDS-PAGE, western blotting, indirect ELISA, and inhibition ELISA using sera from 12 wheat allergic patients. The fractions of albumin, globulin, gliadin and glutenins in wheat flour can be obtained by a one-step extraction with Na2CO3-NaHCO3 (20 mM, pH 9.6, 0.5 M NaCl, 40% ethanol, 1 mM PMSF) in comparison to sequential extractions. Results showed high cross-reactivity in wheat, barley and rye due to close resemblance and high sequence identity (>50%), whereas nearly negligible cross-reactivity among rice, buckwheat, and quinoa was observed. Our research findings suggest that people with wheat allergy should rely primarily on the use of rice, quinoa and non-grain buckwheat, which is an effective substitute for wheat, while those with hypersensitivity should avoid the use of barley and rye in their diet.