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PubMedDate not supplied

Rapid extraction of aflatoxin from creamy and crunchy peanut butter.

A rapid extraction technique was developed for the isolation and subsequent liquid chromatographic determination of aflatoxins B1, B2, G1, and G2 in creamy and crunchy peanut butter. Peanut buftter samples were extracted with a methanol 15% sodium chloride (7 + 3) solution followed by a second extraction with methanol. The extract was subjected to a cleanup using a Vicam Aflatest immunoaffinity column. Control samples for both smooth and crunchy peanut butter were fortified at 4 different levels for aflatoxin B1, B2, G1, and G2. The average aflatoxin B1, B2, G1, and G2 recoveries from smooth peanut buffer were 95.2, 89.9, 94.1, and 62.4%, respectively, and 92.4, 84.3, 85.5, and 53.7%, respectively, from crunchy peanut butter. This extraction method and the official AOAC Method 991.31 produced comparable results for peanut butter samples. This method provides a rapid, specific, and easily controlled assay for the analysis of aflatoxins in peanut butter with minimal solvent usage. Organic solvent consumption was decreased by 85% and hazardous waste production was decreased by 80% in comparison with the AOAC method. Along with the decreased solvent consumption, significant savings in time were observed.

Aflatoxins↗

PubMedDate not supplied

Liquid chromatographic method for determination of aflatoxins B1, B2, G1, and G2 in corn and peanut products: collaborative study.

A collaborative study of a liquid chromatographic method for the determination of aflatoxins B1, B2, G1, and G2 was conducted in laboratories located in the United States, Canada, South Africa, and Switzerland. Twenty-one artificially contaminated raw peanuts, peanut butter, and corn samples containing varying amounts of aflatoxins B1, B2, G1, and G2 were distributed to participating laboratories. The test portion was extracted with methanol-0.1N HCl (4 + 1), filtered, defatted with hexane, and then partitioned with methylene chloride. The concentrated extract was passed through a silica gel column. Aflatoxins B1 and G1 were derivatized with trifluoroacetic acid, and the individual aflatoxins were determined by reverse-phase liquid chromatography with fluorescence detection. Statistical analysis of the data was performed to determine or confirm outliers, and to compute repeatability and reproducibility of the method. For corn, relative standard deviations for repeatability (RSDr) for aflatoxin B1 ranged from 27.2 to 8.3% for contamination levels from 5 through 50 ng/g. For raw peanuts and peanut butter, RSDr values for aflatoxin B1 were 35.0 to 41.2% and 11.2 to 19.1%, respectively, for contamination levels from 5 through 25 ng/g. RSDr values for aflatoxins B2, G1, and G2 were similar. Relative standard deviations for reproducibility (RSDr) for aflatoxin B1 ranged from 15.8 to 38.4%, 24.4 to 33.4%, and 43.9 to 54.0% for corn, peanut butter, and raw peanuts, respectively. The method has been adopted official first action for the determination of aflatoxins B1, B2, G1, and G2 in peanut butter and corn at concentrations greater than or equal to 13 ng total aflatoxins/g.

Aflatoxin B1↗

PubMedDate not supplied

Enzyme immunoassay for determination of peanut proteins in food products.

Food allergy presents a problem for many parts of society, including sensitive subjects, schools, health authorities, and the food industry. Once food allergy is diagnosed, dietary avoidance is the principle method of management. Because trace levels of peanuts can elicit an adverse to fatal reaction, unintentional exposure to the offending allergens may have devastating consequences to sensitive individuals. However, determination of trace amounts of unintentional peanut contamination in our food supply is very difficult. Recently, we developed polyclonal antibodies specific to peanut proteins that do not cross-react with 22 legumes, tree nuts, or other common snack ingredients. An antiserum containing the polyclonal antibodies was used to develop a sensitive enzyme-linked immunosorbent assay (ELISA) for determination of peanut proteins in snack foods. This study reports the first successful ELISA test to detect trace amounts of peanut allergens in a variety of foods. The concentration of peanut protein that inhibited 50% of antibody-antigen binding (IC50) was 12 ng/mL, the linear range was 1-63 ng/mL, and the detection limit was 400 ng/g (ppb) for the various foods tested. Recoveries ranged from 68 to 90%, with coefficients of variation of 2-22%, depending on the commodity. Using this new procedure, allergy-related complaint samples from various food groups were analyzed, and undeclared peanut proteins were identified in some products.

Animals↗

PubMed2001

Oral administration of IL-12 suppresses anaphylactic reactions in a murine model of peanut hypersensitivity.

There is no satisfactory therapeutic intervention for peanut allergy, which accounts for most life-threatening food allergic reactions. Since IL-12 has been found to inhibit allergic airway responses in a mouse model of asthma and to cure Th2 cytokine-mediated murine schistosomiasis, we hypothesized that IL-12 treatment might also inhibit peanut allergic reactions. Consequently, we investigated the effects of oral IL-12 treatment in a murine model of peanut allergy and found that oral administration of liposome encapsulated rIL-12 could both prevent and reverse peanut hypersensitivity and could reduce histamine release, peanut-specific serum IgE and IgG1, and fecal IgA levels. Oral IL-12 treatment also increased IFN-gamma but did not decrease IL-4 or IL-5 levels. We conclude that oral rIL-12 treatment has therapeutic as well as preventive effects on peanut allergy, which are associated with increased IFN-gamma production.

Administration, Oral↗

PubMed2006

[What type of avoidance for peanut allergic children?].

We analyzed, from the literature, the balance benefit/risk of a strict avoidance of peanut in children with peanut allergy. The benefits of a strict avoidance diet seem limited: reactions to the low doses and to the peanut oil refined are rare and most often slight. It is not proven that a strict avoidance facilitates the cure of allergy. On the other hand, strict avoidance could induce a worsening of allergy, with deterioration of quality of life, creation of food neophobia. In case of cure of allergy, it is difficult to normalize the diet after a strict avoidance. Outside of the rare sensitive patients to a very low dose of peanut, for which a strict avoidance is counseled, the report benefits risk is in favor of the prescription of adapted avoidance to the eliciting dose. For the majority of the peanut allergic children, it seems to us that the avoidance can and must be limited to the non hidden peanut.

Allergens↗

PubMed2006

Early-life supplementation of vitamins A and D, in water-soluble form or in peanut oil, and allergic diseases during childhood.

BACKGROUND: Early vitamin supplementation is given routinely to infants in many countries, but it is unclear whether this affects the risk of allergic diseases. OBJECTIVES: We sought to study the association between early-life supplementation of vitamins A and D in water-soluble form or in peanut oil and allergic diseases up to 4 years of age. METHODS: A prospective birth cohort of 4089 newborn infants was followed for 4 years using parental questionnaires repeatedly to collect information on exposure and health. At 4 years, the response rate was 90%, and allergen-specific IgE levels to food and airborne allergens were measured in 2614 of the participating children. RESULTS: Vitamins A and D were given to 98% of the children in infancy, and vitamins based in peanut oil dominated (90%). Children supplemented with vitamins A and D in water-soluble form during the first year of life had an almost 2-fold increased risk of asthma (adjusted odds ratio [OD], 2.18; 95% CI, 1.45-3.28), food hypersensitivity (adjusted OR, 1.89; 95% CI, 1.33-2.65), and sensitization to common food and airborne allergens (adjusted OR, 1.88; 95% CI, 1.34-2.64) at age 4 years compared with those receiving vitamins in peanut oil. No increased risk of IgE antibodies to peanut was seen in children receiving vitamins in peanut oil. CONCLUSION: Supplementation of vitamins A and D in water-soluble form seems to increase the risk of allergic disease up to the age of 4 years compared with supplementation with the same vitamins given in peanut oil. CLINICAL IMPLICATIONS: Vitamins A and D in oil does not seem to increase the risk of allergic disease during childhood.

Air Pollution↗

PubMed2004

Oil, sugar, and starch characteristics in peanut breeding lines selected for low and high oil content and their combining ability.

Peanut seeds contain approximately 50% oil on a dry weight basis, making them a high fat food. Reduction of the oil content would make peanuts a more desirable food to fat conscious consumers. Removal of existing oil by processing is not feasible for in-shell peanuts, the dominant product of the North Carolina-Virginia area. To reduce oil content in in-shell peanuts, a genetic solution must be found. However, while reduced oil content is a desirable objective, changes in oil must not be accompanied by significant decreases in any of the desirable aspects of peanut flavor. Because the impact of selection for low or high oil on flavor is not known, it would be useful to know in what form dry matter is being stored in the seed, particularly if it is not being stored as oil. Screening of 584 accessions identified two lines (PI 269723 and PI 315608) with high and two (Robusto 2 and Robusto 3) with low oil contents, each pair differing in sugar content. The four parents were crossed in diallel fashion to investigate patterns of inheritance. General combining abilities (GCA) for oil content closely followed values of the parental lines. One low oil parent (Robusto 2) had a correspondingly elevated GCA for sugar content, but neither low oil parent had the effect of elevating starch in progeny. Reciprocal cross differences were found for starch and sugar contents, suggesting influences of cytoplasmic genes on those traits. These lines serve as resource material for researchers interested in the genetic and physiological aspects of the oil-sugar-starch relationship in peanuts.

Arachis↗

PubMed2001

Hidden peanut allergens detected in various foods: findings and legal measures.

BACKGROUND: Undeclared allergens in foodstuffs represent a major health problem for sensitized persons. Until recently, most food control authorities were not in the position to monitor hidden allergens and to take legal measures against their presence in foodstuffs. METHODS: In this study, we employed human sera-based immunoassay techniques, enabling semiquantitative detection and identification of peanut allergens in a variety of foodstuffs. RESULTS: This study showed the presence of undeclared allergens in products belonging to various food categories, such as cereals, cookies, cakes, and snacks. The detection limit for peanut contamination was in most instances less than 50 mg peanut material per kg, i.e., less than about 5 mg peanut allergens per kg. We legally objected to products with more than one part per thousand or 1000 mg/kg of peanut contamination. CONCLUSIONS: In most cases, food producers, confronted with our results, were able to detect and eliminate the sources of the contamination. They implemented measures to prevent the presence of hidden peanut allergens in their products, increasing food safety for sensitized persons and overall food quality.

Allergens↗

PubMed1998

Isolation and characterization of proteic allergens in refined peanut oil.

Allergic reactions to peanut oil are very much debated, even if the responsibility of peanut oil has been evoked in several cases of adverse reactions, including death related to severe asthma. The aim of the present study was to investigate the presence of allergenic proteins in peanut oil. Proteins were extracted from commercial refined peanut oil, with a relative content in the order of 0.1-0.2 microg per g of oil, and molecular sizes ranging from 14 up to 76kDa in SDS-PAGE. Eight protein bands were systematically observed in crude, neutralized and refined oils, with a molecular mass ranging from approximately 14 to 76 kDa, including one at 18 kDa which was identified by Western blot performed with serum from two allergic patients. The protein extract gave positive IgE-RIA with patient sera, positive in vitro leucocyte histamine release tests and positive skin-prick tests in allergic patients. The allergenic protein was purified by HPLC and [125I] iodide-labelled. It had an isoelectric point at 4.5 in isoelectrofocusing. In conclusion, we have demonstrated the presence of allergenic proteins in crude and refined peanut oil. These proteins are the same size as two allergens previously described in peanut protein extracts.

Adolescent↗

PubMed2003

Comparison of commercially available ELISA kits with human sera-based detection methods for peanut allergens in foods.

Undeclared peanut allergens as contaminants in foodstuffs represent a major health problem for sensitized persons. Various immunochemical techniques are employed to detect and quantify peanut allergens. There is an urgent need to compare and standardize those test systems to enable comparable allergen analyses of foodstuffs, comparable studies, and consequent and consistent measures against the presence of hidden peanut allergens. The present study compared commercially available peanut ELISA kits with human sera-based immunoassay techniques (dot blotting and Western blotting), enabling semiquantitative and quantitative detection, and identification of peanut contaminants in foodstuffs. Additionally, the effect of conventional roasting conditions on the detection and quantification of peanut with the selected methods was investigated.

Allergens↗

PubMed2005

Inter-laboratory validation study of five commercial ELISA test kits for the determination of peanut proteins in biscuits and dark chocolate.

The results of an inter-laboratory study with five commercially available peanut ELISA test kits to detect and quantify peanut residues in two food matrices (biscuit and dark chocolate) at four different concentrations (0-10 mg peanut kg(-1) matrix corresponding to about 0-2.5 mg peanut protein kg(-1) matrix) are reported. In general the five ELISA test kits evaluated could detect peanut protein in the two food matrices. In three cases, the study challenged the test kits beyond their intended use for quantification below the manufacturers' defined cut-off limits. Generally, all five ELISA test kits performed well in the concentration range 5-10 mg kg(-1) rather than in the low concentration range (2.0 or 2.5 mg kg(-1)). The variation in the found recoveries of peanut between the different test kits had a spread of 44-191% across all concentrations. The quantification characteristics between test kits differed significantly at the very low mg kg(-1) level. Two test kits performed well even at concentrations below 5 mg kg(-1) with reproducibilities of 27-36% for biscuits and 45-57% for chocolate.

Arachis↗

PubMed2006

Efficacy of oral iodized peanut oil is greater than that of iodized poppy seed oil among Indonesian schoolchildren.

BACKGROUND: Oral iodized poppy seed oil is an appropriate measure for controlling iodine deficiency in areas where iodized salt is not yet available. However, a more effective and cheaper iodized oil preparation is needed. OBJECTIVE: The aim of this study was to compare the efficacy of iodized peanut oil with that of iodized poppy seed oil. DESIGN: Schoolchildren aged 8-10 y were supplemented with a single oral dose of iodized peanut oil (P200, P400, or P800 mg I), iodized poppy seed oil (PS400 mg I), or peanut oil (placebo). The concentration of urinary iodine (UI) was measured at 0, 4, 12, 25, and 50 wk, whereas thyroid volume and serum thyrotropin and free thyroxine concentrations were measured at 0, 25, and 50 wk. RESULTS: UI was higher in all treatment groups than in the placebo group, except at baseline. UI in the P200 group was not significantly different from that in the PS400 group at all times of measurement. In a comparison of preparations supplying 400 mg I conducted by using a mathematical model, iodine retention from the peanut oil preparation was 3 times that from the poppy seed oil, and the protection period for peanut oil was twice as long as that for the poppy seed oil (P < 0.001 for both). The reduction in thyroid volume was greater in the treatment groups than in the placebo group (P < 0.001). No significant differences in serum hormone concentrations were observed between groups before or after treatment. CONCLUSION: Iodized peanut oil is more efficacious in controlling iodine deficiency than is iodized poppy seed oil containing the same amount of iodine.

Administration, Oral↗

PubMed2005

Towards immunotherapy for peanut allergy.

PURPOSE OF REVIEW: Food allergy is a major cause of life-threatening hypersensitivity reactions. Peanut allergy is the most serious of the hypersensitivity reactions to foods due to its persistence and high risk of severe anaphylaxis. Currently, strict avoidance of the allergenic food and ready access to self-injectable epinephrine is the 'standard of care' for food allergy. Based on extensive characterization of food allergens and a better understanding of the immunological mechanisms underlying allergic disease, promising therapeutic modalities for food allergy treatment and prevention are being developed. RECENT FINDINGS: Immunotherapeutic strategies include peptide immunotherapy, mutated protein immunotherapy and DNA immunization, which all strive to decrease the deleterious Th2 response. Another approach already in clinical trials for peanut allergy is the anti-IgE therapy which prevents circulating IgE from binding to effector cells, consequently decreasing clinical symptoms after peanut ingestion. In order to be applicable, these strategies must be well tolerated, inexpensive and easily administered. Realistic treatment options would likely involve a combination of different approaches. SUMMARY: Food allergy affects approximately 4-6% of children and 3-4% of adults. Peanut allergy can be devastating as reactions range from urticaria to severe anaphylactic shock and death. The only preventive measure for peanut allergy is strict avoidance of the incriminating food. It is likely immunotherapy will be available in the near future as a well tolerated and effective therapy for treating peanut allergy. The use of the anti-IgE therapy in conjunction with other immunotherapy would possibly be the best treatment option in the future.

Allergens↗

PubMed2005

Characterization of the T-cell epitopes of a major peanut allergen, Ara h 2.

BACKGROUND: The development of safe and effective immunotherapy for peanut allergy has been complicated by the high anaphylactic potential of native peanut extracts. We sought to map the T-cell epitopes of the major peanut allergen, Ara h 2 in order to develop T-cell targeted vaccines. METHODS: A panel of eight peanut-specific CD4+ T-cell lines (TCL) was derived from eight peanut-allergic subjects and proliferative and cytokine responses to stimulation with a set of overlapping 20-mer peptides representing the entire sequence of Ara h 2 determined. Proliferation was assessed in 72 h assays via tritiated thymidine incorporation, while interleukin (IL)-5 and interferon (IFN)-gamma production were assessed via sandwich enzyme-linked immunosorbent assay (ELISA) of cell culture supernatants. RESULTS: Eight of the 17 Ara h 2 peptides were recognized by one or more subjects, with the two peptides showing highest reactivity [Ara h 2 (19-38) and Ara h 2 (73-92)] being recognized by three subjects each. Adjoining peptides Ara h 2 (28-47) and Ara h 2 (100-119) induced proliferative responses in two subjects. Each of these peptides was associated with a Th2-type cytokine response. CONCLUSION: Two highly immunogenic T-cell reactive regions of Ara h 2 have been identified, Ara h 2 (19-47) and Ara h 2 (73-119), providing scope for the development of safe forms of immunotherapy for peanut allergy.

2S Albumins, Plant↗

PubMed2005

Allergen immunotherapy with heat-killed Listeria monocytogenes alleviates peanut and food-induced anaphylaxis in dogs.

BACKGROUND: Heat-killed Listeria monocytogenes (HKL) potently stimulates interferon (IFN)-gamma production in CD4 T-lymphocytes, and when used as adjuvant for immunotherapy, reduces immunoglobulin (Ig)E production and reverses established allergen-induced airway hyperreactivity (AHR) in a murine model of asthma. We asked if such treatment could decrease established peanut-induced anaphylaxis or cow's milk-induced food allergy in highly food-allergic dogs. METHODS: We therefore studied four 4-year-old atopic colony dogs extremely allergic to peanut (Group I), as well as five 7-year-old dogs very allergic to wheat, milk and other foods (Group II). All dogs experienced marked allergic symptoms, including vomiting and diarrhea on oral challenge with the relevant foods. The dogs were then vaccinated once subcutaneously with peanut or milk and wheat with HKL emulsified in incomplete Freund's adjuvant. RESULTS: Following vaccination of the allergic dogs with HKL and allergen, oral challenges with peanut (Group I) or milk (Group II) elicited only minor or no symptoms. In addition, skin test end-point titrations showed marked reductions for >10 weeks after treatment, and levels of Ara h 1-specific IgE in serum of peanut sensitive dogs, as demonstrated by immunoblotting, were greatly reduced by treatment with HKL plus peanut allergen. CONCLUSIONS: Thus, HKL plus allergen treatment markedly improved established food allergic responses in dogs, suggesting that such an immunotherapy strategy in humans might greatly improve individuals with food allergy and anaphylaxis.

Allergens↗

PubMed2004

General paediatricians and the case of resolving peanut allergy.

Children with peanut allergy are almost always advised to avoid nuts for life. There have been recent reports from academic centres that in some cases the allergy might resolve and thus these dietary restrictions can be lifted. To evaluate resolution of peanut allergy in a selected group of children in a general paediatric setting. Children 4-16 yr old with a clear history of an allergic reaction to peanuts who had not had any reaction in the previous 2 yr were eligible. Specific immunoglobulin E (IgE) or skin prick test (SPT) at the time of diagnosis was sought. A SPT and specific IgE was then done and if this was <or= 8 mm and <or= 17.5 kU[A]/l respectively, a double-blind placebo-controlled food challenge was undertaken. A negative challenge consisted of tolerance to a cumulative dose of 15.8 g peanuts followed by an open challenge. From the 82 case notes reviewed 54 children were eligible to participate. Twenty-nine agreed to participate and underwent SPT (29) and specific IgE (28). Of these children eight were eligible for food challenge. Four challenges were negative and four positive. Peanut allergy may resolve in approximately 15% of selected children attending an allergy clinic run by general paediatricians in a district general hospital. Food challenge constitutes the appropriate way of removing the burden that comes with a diagnosis of peanut allergy and enables dietary restriction to cease.

Adolescent↗

PubMed2025

A single hybrid origin of cultivated peanut.

This study, the first in a three-part series, lays the foundation for understanding the origin of the peanut crop (Arachis hypogaea). Its subsequent evolution is explored in the two papers that follow. The evidence that A. hypogaea originated from a single hybridization event between Arachis duranensis and Arachis ipaënsis less than 10 000 years ago was already very strong. Here, we extend this evidence using more than 1600 single-nucleotide polymorphisms to make an almost exhaustive comparison of wild Arachis section germplasm conserved ex situ with the A and B subgenomes of divergent, sequenced cultivated peanuts. The wild relatives of peanut are highly selfing and their geocarpy means they plant their own seeds, allowing them to persist as discrete populations for millennia. This unusual biology creates a rare opportunity for genetic archaeology: ancestral lineages can be identified with exceptional precision. Our results reaffirm a single origin for the cultigen, identifying A. duranensis from Río Seco and A. ipaënsis K 30076 as the closest known relatives of the A and B subgenomes of peanut. As a genomic resource, we generated a chromosome-scale assembly of the Río Seco A. duranensis K 30065 and confirmed that it is more closely related to the A subgenome of peanut than the current reference genome (V14167). Even if somewhat closer wild accessions were found through new field collections, they would still belong to the same ancestral lineage. With this level of evidence, the origin of peanut is now known in greater detail than that of any other ancient polyploid crop.

Arachis↗

PubMed1994

Identification of peanut agglutinin and soybean trypsin inhibitor as minor legume allergens.

Peanuts and soybeans are frequent causes of food hypersensitivity reactions in children. Sera from 12 patients with atopic dermatitis and a positive double-blind placebo-controlled food challenge to peanut and sera from 5 patients with atopic dermatitis and a positive double-blind placebo-controlled food challenge to soybean were used to identify and characterize specific legume allergens. Identification of a minor allergen from peanut and a minor allergen from soybean was accomplished using various physicochemical techniques. The peanut fraction, peanut agglutinin, isolated by anion-exchange chromatography and electrolution and confirmed by amino acid sequencing, bound IgE in only 50% of the peanut challenge positive patients. The soybean fraction, soybean trypsin inhibitor, identified by gel filtration and electroelution and confirmed by amino acid sequencing, bound IgE in only 20% of the soy challenge positive patients. The identification of these two known legume proteins as minor allergens should allow further immunologic and structural investigations to compare the major and minor legume allergens.

Allergens↗