Early introduction of peanuts.
Peanut allergy is the most common food allergy and the leading cause of anaphylaxis and death due to food allergy. Despite previous guidelines created by the American Academy of Pediatrics in 2003, peanut allergy has continued to significantly increase over the past decade. Therefore, further research has been done to help clinicians provide more evidence-based recommendations about the timing of introduction of peanuts. The LEAP study, published in February 2015, demonstrated the value of much earlier introduction of peanuts to nonallergic patients than previously suggested. These findings have altered current practice, and recommendations supported by the American Academy of Pediatrics now allow the introduction of peanuts as early as age 4 months to reduce the likelihood of developing peanut allergy.
Detection of Food Allergens by Taqman Real-Time PCR Methodology.
Real-time PCR (polymerase chain reaction) has shown to be a very effective technology for the detection of food allergens. The protocol described herein consists on a real-time PCR assay targeting the plant ITS (Internal Transcribed Spacer) region, using species-specific primers and hydrolysis probes (Taqman) dual labeled with a reporter fluorophore at the 5' end (6-carboxyfluorescein, FAM) and a quencher fluorophore at the 3' end (Blackberry, BBQ). The species-specific real-time PCR systems (primers/probe) described in this work allowed the detection of different nuts (peanut, hazelnut, pistachio, almond, cashew, macadamia, walnut and pecan), common allergens present in commercial food products, with a detection limit of 0.1 mg/kg.
Validation of Recipes for Double-Blind Placebo-Controlled Challenges With Milk, Egg White, and Hazelnut.
BACKGROUND: The double-blind, placebo-controlled food challenge (DBPCFC) is considered the definitive diagnostic test for food allergy. Nevertheless, validated recipes for masking the foods are scarce, have not been standardized, and differ between centers. Sensory evaluation techniques such as the triangle test are necessary to validate the recipes used for DBPCFC. METHODS: We developed 3 recipes for use in DBPCFC with milk, egg white, and hazelnut and used the triangle test to validate them in a 2-phase study in which 197 volunteers participated. In each phase, participants tried 3 samples (2 active-1 placebo or 2 placebo-1 active) and had to identify the odd one. In phase 1, the 3 samples were given simultaneously, whereas in phase 2, the 3 samples of foods that failed validation in phase 1 were given sequentially. A visual analog scale (VAS) ranging from 1 to 10 was used to evaluate how much participants liked the recipes. RESULTS: In phase 1, the egg white recipe was validated (n=89 volunteers, 38.9% found the odd sample, P=.16). Milk and hazelnut recipes were validated in phase 2 (for both foods, n=30 participants, 36.7% found the odd sample, P=.36). Median VAS scores for the 3 recipes ranged from 6.6 to 9.7. CONCLUSIONS: We used sensory testing to validate milk, egg white, and hazelnut recipes for use in DBPCFC. The validated recipes are easy to prepare in a clinical setting, provide the equivalent of 1 serving dose, and were liked by most participants.
Detection of Food Allergens by Phage-Displayed Produced Antibodies.
Phage display is a powerful tool to produce recombinant antibodies against a given antigen without animal immunization. This technology employs libraries of recombinant bacteriophages that display billions of different functional antibody fragments on their surface. They are selected by panning in vitro against the target antigen in search for specific binders. In this chapter, we describe the selection of single chain variable fragment (scFv) antibodies to be used for detection of allergenic proteins from nuts in food products. The artificial libraries TomLinson I+J (MRC Laboratory of Molecular Biology and MRC Centre for Protein Engineering) were employed that resulted in successful phage-ELISA systems for detection of almond and walnut proteins in commercial food products.
Drying and decontamination of raw pistachios with sequential infrared drying, tempering and hot air drying.
Pistachio nuts have been associated with outbreaks of foodborne disease and the industry has been impacted by numerous product recalls due to contamination with Salmonella enterica. The current hot air drying of pistachios has low energy efficiency and drying rates, and also does not guarantee the microbial safety of products. In the study described herein, dehulled and water-sorted pistachios with a moisture content (MC) of 38.14% (wet basis) were dried in a sequential infrared and hot air (SIRHA) drier to <9% MC. The decontamination efficacy was assessed by inoculating pistachios with Enterococcus faecium, a surrogate of Salmonella enterica used for quality control in the almond industry. Drying with IR alone saved 105min (34.4%) of drying time compared with hot air drying. SIRHA drying of pistachios for 2h with infrared (IR) heat followed by tempering at a product temperature of 70°C for 2h and then by hot air drying shortened the drying time by 40min (9.1%) compared with drying by hot air only. This SIRHA method also reduced the E. faecium cell population by 6.1-logCFU/g kernel and 5.41-logCFU/g shell of pistachios. The free fatty acid contents of SIRHA dried pistachios were on par with that of hot air dried samples. Despite significant differences in peroxide values (PV) of pistachio kernels dried with the SIRHA method compared with hot air drying at 70°C, the PV were within the permissible limit of 5Meq/kg for edible oils. Our findings demonstrate the efficacy of SIRHA drying in achieving simultaneous drying and decontamination of pistachios.
A Limited Survey of Dark Chocolate Bars Obtained in the United States for Undeclared Milk and Peanut Allergens.
Undeclared allergens in chocolate products have been responsible for numerous allergen-related recalls in the United States. A survey was conducted to determine the prevalence of undeclared milk and peanut in 88 and 78 dark chocolate bars, respectively. Concentrations of milk (as nonfat dry milk) or peanut in three samples of each chocolate product were determined with two milk- or peanut-specific enzyme-linked immunosorbent assay kits. In 75% of the chocolate bar products with a milk advisory statement, milk concentrations were above the limit of quantitation (2.5 μg/g [ppm]), with the majority having concentrations >1,000 ppm. An additional 67% of chocolate bars with a "traces of milk" statement contained 3 to 6,700 ppm of milk. Fifteen percent of chocolates labeled dairy free or lactose free and 25% labeled vegan were positive for milk, all with concentrations >1,000 ppm. Even for chocolates with no reference to milk on the label, 33% of these products contained 60 to 3,400 ppm of milk. The survey of chocolate products for peanuts revealed that 8% of products with an advisory statement contained peanut, with the highest concentration of 550 ppm. All nine chocolates bearing the peanut-free or allergen-free statement were negative for peanut, but 17% of chocolates with no label statement for peanut were positive for peanut at concentrations of 9 to 170 ppm. Evaluation of multiple lots of four chocolate products revealed that milk was consistently present or absent for the products investigated, but mixed results were obtained when multiple lots were tested for peanut. This study indicates that a large proportion of dark chocolate bars contain undeclared milk. The type of advisory statement or the absence of a milk advisory statement on products did not predict the amount or absence of milk protein. In contrast, a lower proportion of chocolates containing undeclared peanut was found. Consumers with food allergies should be cautious when purchasing dark chocolate products, particularly those that have an advisory label statement.
Influence of japanese consumer gender and age on sensory attributes and preference (A case study on deep-fried peanuts).
BACKGROUND: Detailed exploration of sensory perception as well as preference across gender and age for a certain food is very useful for developing a vendible food commodity related to physiological and psychological motivation for food preference. Sensory tests including color, sweetness, bitterness, fried peanut aroma, textural preference, and overall liking of deep-fried peanuts were carried out using 417 healthy Japanese consumers with varying frying time (2, 4, 6, 9, 12, and 15 min) at 150 °C. To determine the influence of gender and age on sensory evaluation, systematic statistical analysis including one-way analysis of variance (ANOVA), polynomial regression analysis, and multiple regression analysis were conducted using the collected data. RESULTS: The results indicated that females were more sensitive to bitterness than males. This may affect sensory preference; female subjects favored peanuts prepared with a shorter frying time more than male subjects did. With advancing age, textural preference played a more important role in overall preference. Older subjects liked deeper-fried peanuts, which are more brittle, more than younger subjects did. CONCLUSION: In the present study, systematic statistical analysis based on collected sensory evaluation data using deep-fried peanuts was conducted, and the tendency of sensory perception and preference across gender and age were clarified. These results may be useful for engineering optimal strategies to target specific segments to gain greater acceptance in the market.
Peanut Allergen Threshold Study (PATS): Novel single-dose oral food challenge study to validate eliciting doses in peanut allergic children.
BACKGROUND: Eliciting doses (ED) of allergenic foods can be defined by the distribution of threshold doses for individuals within a specific population. ED05 is the dose that elicits a reaction in 5% of allergic subjects. The predicted ED05 for peanut (PN) is 1.5 mg of peanut protein (6 mg whole peanut). OBJECTIVE: We sought to validate the predicted peanut ED05 (1.5 mg) with a novel single dose challenge. METHODS: Consecutive eligible peanut allergic children in 3 centres were prospectively invited to participate, irrespective of previous reaction severity. Predetermined criteria for objective reactions were used to identify ED05 single dose reactors. RESULTS: 518 children (mean age 6.8 years) were eligible. No significant demographic or clinical differences were identified between 381(74%) participants and 137 (26%) non-participants or between subjects recruited at each centre. 378 children (206 male) completed the study. Almost half the group reported ignoring precautionary allergen labelling. 245 (65%) experienced no reaction to the single dose of peanut. 67 (18%) reported a subjective reaction without objective findings. 58 (15%) experienced signs of a mild and transient nature that did not meet the pre-determined criteria. Only 8 subjects (2.1%, 95% CI 0.6%-3.4%) met the pre-determined criteria for an objective and likely related event. No child experienced more than a mild reaction, 4 of the 8 received oral antihistamines only and none received epinephrine. Food allergy related quality of life improved from baseline to 1 month post challenge regardless of outcome (eta squared = 0.2, p <0.0001). Peanut SPT, peanut and Ara h 2 spIgE levels were not associated with objective reactivity to PN ED05. CONCLUSION: A single administration of 1.5 mg PN protein elicited objective reactions in fewer than the predicted 5% of peanut-allergic subjects. The novel single dose OFC appears clinically safe and patient-acceptable, regardless of the outcome. It identifies the most highly dose-sensitive food allergic population, not otherwise identifiable using routinely available peanut SPT or spIgE levels but this single-dose approach has not yet been validated for risk assessment of individual patients.
Quantification of Inositol Phosphates in Almond Meal and Almond Brown Skins by HPLC/ESI/MS.
The extraction and measurement of all six forms of inositol phosphates (InsPs) in almond meal and brown skins were improved from existing methods by pH adjustment, supplementation of EDTA, and rapid analysis via anion-exchange high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. The quantity of InsPs in six major almond cultivars ranged from 8 to 12 lmol/g in the meal and 5 to 14 lmol/g in the brown skins. InsP6 was the dominant form, but lower forms still accounted for 20% of the total InsPs molar concentration in a majority of the samples. InsPs contributed 32–55% of the organic phosphorus content and 20–38% of the total phosphorus content in the meal. In brown skins, these ranges were 44–77% and 30–52%, respectively. The successful application of this analytical method with almonds demonstrates its potential use for re-examination of the reported phytic acid contents in many other tree nuts, legumes, grains, and complex foods.
Chemical and sensory characterization of oxidative changes in roasted almonds undergoing accelerated shelf-life.
Peroxide values [PV], free fatty acid values [FFAs], conjugated dienes [CD], tocopherols, headspace volatiles and consumer hedonic response were measured in light roast [LR] and dark roast [DR] almonds stored under conditions that promote rancidity development over 12 months. Results demonstrate that although rancidity develops at different rates in LR and DR almonds, consumer liking was not significantly different between these almonds. Average hedonic ratings fell below 5 ("neither like nor dislike") by 6 months of storage. This did not correspond with recommended industry rejection standards of PV <5 mEq and FFA <1.5 % oleic. FFAs remain well below <1.5% oleic during storage indicating that FFAs are not a good marker of rancidity in roasted almonds stored in low humidity environments. Regression of consumer liking to rancidity indicators revealed that select headspace volatiles including: heptanal, octanal, nonanal, 2-octenal, 2-heptanone, 2-pentylfuran, hexanal, and pentanal, correlate better with liking than non-volatile indicators.