Peanut Residue Research Articles

Effect of Agricultural Residues Based-Compost on the Yield of Amarantus hybridus L. (Amaranthaceae) in Gbado-Lite City, Nord-Ubangi (Democratic Republic of the Congo)

An experimental study was conducted in Gbadolite city to develop composts from peanut (Groundnut) and maize residues alone or combined. The study found that plots modified with compost based on peanut (Groundnut) residues combined with corn residues are of good quality compared to non-waste compost combined and unamended plots as indicated by the average values of plant height (91.9±0.79 cm vs. 54.0±1.35 cm), diameter at the collar (12.66±0.47 mm vs. 9.00±1.41 mm); number of leaves ( 20.6±0.47 vs. 15.6±0.47); leaf lengths (23.5±1.17 cm vs. 19.4±1.92 cm ); leaf widths (7.32±0.44 cm vs. 6.34±0.68 cm) yield per hectare ( 22.63±0.67T/ha vs 11.51±2.85 T/ha ). It is therefore desirable that compost be characterized from a physical-chemical point of view (pH, minerals, C/N ratio, etc.) and considers the production of other plants grown on this substrate in order to assess its effectiveness.

Fungal endophyte Phomopsis liquidambari biodegrades soil resveratrol: a potential allelochemical in peanut monocropping systems

Most allelochemicals are secondary products released from root excretions or plant residues that accumulate in continuous cropping systems and cause severe decline in peanut yield. Resveratrol is a plant-derived stilbene that is released from peanut residues and accumulates in the soil; however, its allelopathic effects on peanut production are overlooked. Effective management solutions need to be developed to relieve allelopathy caused by soil resveratrol. Here, the biodegradation of resveratrol by the fungal endophyte Phomopsis liquidambari was investigated in a mineral salt medium and a soil trial. Resveratrol and its metabolites (produced by degradation by P. liquidambari) were detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Resveratrol released from peanut residues reached a maximum concentration of 0.18 μg g-1 soil in litterbag experiments. Exogenous resveratrol inhibited peanut growth, nodule formation, and soil dehydrogenase activity, and reduced the soil microbial biomass carbon content and bacterial abundance, indicating an allelopathic role in peanut growth. More than 97% of the resveratrol was degraded within 72 and 168 h by P. liquidambari in pure culture and soil conditions, respectively. Resveratrol was first cleaved to 3,5-dihydroxybenzaldehyde and 4-hydroxybenzaldehyde, which were subsequently oxidized into 3,5-dihydroxybenzoic acid and 4-hydroxybenzoic acid, respectively. Fungal resveratrol cleavage oxygenase and the related gene expression were enhanced when P. liquidambari was induced by the resveratrol during the incubation. Our results indicate that the practical application of the fungal endophyte P. liquidambari has strong potential for biodegrading soil resveratrol, which can cause allelopathy in peanut continuous cropping systems. © 2019 Society of Chemical Industry.

Nitrogen Contributions from Peanut Residues to Subsequent Crops

There is not enough evidence to support current peanut N credit recommendations in the Southeast. Nitrogen is released rapidly from peanut residues, and it moves quickly through light-textured soils found in this region. Only a relatively small amount of N from peanut residues is available when subsequent crops need it. This new 5-page document discusses peanut nitrogen credits, nitrogen release from peanut residues, crop performance following peanut, tillage and nitrogen release, and peanut residue distribution and nitrogen release. Written by Arun Jani and Michael J. Mulvaney, and published by the UF/IFAS Agronomy Department, April 2019. http://edis.ifas.ufl.edu/ag431

Estimates on nitrogen uptake in the subsequent wheat by above-ground and root residue and rhizodeposition of using peanut labeled with 15N isotope on the North China Plain

Leguminous crops play a vital role in enhancing crop yield and improving soil fertility. Therefore, it can be used as an organic N source for improving soil fertility. The purpose of this study was to (i) quantify the amounts of N derived from rhizodeposition, root and above-ground biomass of peanut residue in comparison with wheat and (ii) estimate the effect of the residual N on the wheat-growing season in the subsequent year. The plants of peanut and wheat were stem fed with 15N urea using the cotton-wick method at the Wuqiao Station of China Agricultural University in 2014. The experiment consisted of four residue-returning strategies in a randomized complete-block design: (i) no return of crop residue (CR0); (ii) return of above-ground biomass of peanut crop (CR1); (iii) return of peanut root biomass (CR2); and (iv) return of all residue of the whole peanut plant (CR3). The 31.5 and 21% of the labeled 15N isotope were accumulated in the above-ground tissues (leaves and stems) of peanuts and wheat, respectively. N rhizodeposition of peanuts and wheat accounted for 14.91 and 3.61% of the BG15N, respectively. The 15N from the below-ground 15N-labeled of peanuts were supplied 11.3, 5.9, 13.5, and 6.1% of in the CR0, CR1, CR2, and CR3 treatments, respectively. Peanut straw contributes a significant proportion of N to the soil through the decomposition of plant residues and N rhizodeposition. With the current production level on the NCP, it is estimated that peanut straw can potentially replace 104 500 tons of synthetic N fertilizer per year. The inclusion of peanut in rotation with cereal can significantly reduce the use of N fertilizer and enhance the system sustainability.

Shared Cooking Equipment in Restaurants: A Quantitative Risk Assessment for Peanut-Allergic Consumers

Previous research confirmed the potential risk of accidental exposure to peanut for peanut-allergic consumers if dining at restaurants that share utensils when preparing various Asian dishes. The current study further expands knowledge surrounding possible transfer of peanut residue through shared cooking equipment. Shared equipment kitchen-based experiments were performed to investigate possible transfer of peanut-containing sauces into peanut-free dishes. The amount of residue (mg) sticking to professional cooking equipment (wok, sauce pan, mixing bowl) was measured after preparation of single-serve meals, before and after cleaning. Peanut-containing versions of popular sauces were used to represent three major themes in Asian cooking: sugar-based Pad Thai and General Tso’s sauces, and an oil-based Indian coconut curry. Shared cooking equipment had mean potential transfer amounts of 830 – 15800 mg sauce (48 – 1559 mg peanut protein), dependent on equipment and recipe. In the majority of cases (32 of 35), no measurable residue was found after common cleaning practice (brief scrub with brush and warm water, no dishwasher sanitation assistance). However, in a few cases, up to 0.2 g sauce residue (up to 20 mg peanut protein) remained after cleaning. Warm water and brush cleaning reduces the amount of peanut residue. Nevertheless there is a remaining risk of accidental exposure to peanut. Prior dose-response research indicates that 25% of the peanut-allergic population is predicted to have an allergic reaction when exposed to 20 mg peanut protein. This study confirms potential risk to a peanut-allergic consumer when Asian restaurants cook with shared pans or mixing bowls.

Improved extraction of peanut residues from a wheat flour matrix for immunochemical detection

The efficacy of different buffers in extracting peanut from a solid model food incurred with peanut and subjected to processing was evaluated using two commercial ELISA kits: Veratox® for peanut allergen and peanut ELISA from Morinaga. Average percentage recoveries of peanut from unprocessed samples using the kit supplied buffers were 46 ± 5 and 28 ± 2 with the Veratox and Morinaga kits, respectively. However, Na2CO3, pH 9.6 and PBS containing 1 M GuHCl recovered 65% ± 4% and 77% ± 10% of peanut, respectively from unprocessed samples with the Veratox kit. These two buffers also performed better than the Veratox buffer with fried, high pressure processed, and baked samples. PBS containing SDS and β-ME, performed significantly better than the Morinaga buffer in recovering peanut from unprocessed, boiled and fried samples. Thus, the use of alternative extraction buffers provides better recovery of peanut residues from a processed solid food matrix.

Peanut residue distribution gradients and tillage practices determine patterns of nitrogen mineralization

Peanut (Arachis hypogaea L.) harvest practices create residue distribution gradients in the field that lead to spatial and temporal variability in available nitrogen (N) during subsequent crop growth. The objective of this study was to quantify N mineralization from peanut residue loading rates that are reflective of postharvest residue distribution gradients under simulated conventional and conservation tillage. A field study was conducted in Florida, USA beginning in September 2015. Fresh shoot residues were placed in litterbags at loading rates (1.1, 2.2, 4.5, and 6.7 Mg ha−1 on an air-dry weight basis) that were based on the residue distribution gradient measured in the field following harvest. Three tillage scenarios were simulated by placing litterbags on the soil surface (no-till) or burying them at 0.10 m depth in fall or spring (fall and spring tillage, respectively). Litterbags were retrieved periodically over 365 days. Buried residues mineralized N faster than surface residues, even when buried residues had high levels of recalcitrant fractions, as was the case with spring-incorporated residues. Exponential models predicted that during a wheat (Triticum aestivum L.) crop, residue loading rates of 1.1, 2.2, 4.5, and 6.7 Mg ha−1 would mineralize 3–6, 5–12, 24–34, and 35–41 kg N ha−1, respectively, depending on tillage practice. At the same loading rates, N mineralization estimates dropped to 2–4, 3–6, 9–11, and 5–18 kg N ha−1 during a hypothetical cotton (Gossypium hirsutum L.) crop planted the following spring. These results suggest that peanut harvest and tillage practices cause large spatial and temporal variability in available N following harvest and may partially explain inconsistencies and spatial variability in subsequent crop performance when peanut residues are relied upon as a N source and mineral N fertilization is reduced.

Pinto peanut cover crop nitrogen contributions and potential to mitigate nitrous oxide emissions in subtropical coffee plantations

Many coffee (Coffea arabica L) production systems are characterised by high use of nitrogen (N) fertilisers, which can result in N leaching and emissions of nitrous oxide (N2O). We investigated the potential for legume cover crops grown inter-row to provide N for coffee trees and lower seasonal N2O emissions compared to poultry litter amendment at two subtropical field sites over 12 months, with unfertilised traditional grass groundcover used as a control treatment. Groundcovers (legume and grass treatments) were slashed from the inter-row into the tree line every 2–6 weeks as per normal farming operations. The prostrate ground cover legume Pinto peanut (Arachis pintoi) produced 4–5 t ha−1 biomass at both sites over the 12 month period, and fixed 146 kg N ha−1 year−1 at one site as estimated using the 15N natural abundance method. Background emissions from soil were lower at site 1 (0.38 kg N2O-N ha−1 year−1) than site 2 (2.26 kg N2O-N ha−1 year−1) reflecting differences in soil N and C levels at the sites. The use of Pinto peanut residues as an N amendment didn't result in any N2O flux events beyond those observed in the traditional groundcover control treatment across the season at either site, while the application of poultry litter to match farmer practice at these sites led to a major emission event. Ultimately, the Pinto peanut cover crop treatment led to a lower emission factor than for poultry litter at both sites, and resulted in significantly lower cumulative seasonal emissions for the legume cover crop (0.34 kg N2O-N ha−1 season−1) than poultry litter amendment (0.68 kg N2O-N ha−1 season−1) at site 1 despite similar inputs of N into the system. These findings suggest cover crop legumes could be integrated into coffee plantations to offset a portion of external N inputs, while lowering N2O emissions.

The Alleopathic Compound Luteolin from Peanut Litter Affects Peanut Nodule Formation and the Rhizosphere Microbial Community

Core Ideas Flavonoid luteolin can accumulate in consecutively monocultured peanut fields. Luteolin treatment changes the rhizosphere microbial community of peanut. Flavonoid luteolin in peanut residues may cause continuous cropping obstacles. The flavonoid luteolin is a common flavone released from peanut (Arachis hypogaea L.) residues. Luteolin accumulates in consecutively monocultured soil and affects the growth and nodulation of continuously cropped peanut. A microcosm experiment was performed to determine the effects of luteolin released from peanut residue on peanut nodule formation and on the rhizosphere soil microbial community. Luteolin reached a maximum concentration of 0.42 μg g−1 soil in litterbag experiments, and the half‐life of luteolin at 2.5 to 40 μg g−1 soil varied from 1.13 to 2.91 d. Results from pot experiments indicate that soil with luteolin treatment inhibited peanut seedling nodulation and growth, soil dehydrogenase activity, microbial biomass carbon content, biofilm formation, and chemotactic response of Rhizobium sp. and changed the microbial community structures and abundances at concentration of luteolin as low as 0.42 μg g−1 in soil. This might explain why peanut performs poorly with continuous consecutive monocropping.

Cow manure-loaded biochar changes Cd fractionation and phytotoxicity potential for wheat in a natural acidic contaminated soil

The current study aims to investigate the implications of amending a soil contaminated with Cd with peanut residues biochar (BP) solely or in combination with cow manure (CMPB) at different rates on phytotoxicity of Cd for wheat plants and its distribution in a mine contaminated soil. Soil pH and EC increased progressively in soils amended with either PB or CMPB. Exchangeable Cd was decreased while its non-exchangeable fractions were increased. Dry weights of wheat straw, roots and grains increased when soils amended with either PB or CMPB, especially at the higher application rate. Such increases were correlated significantly with the extractable soil-Cd. Concentrations of Cd in roots were higher than those in straw; whereas, the concentrations in grains seemed to be the lowest. Generally, values of bio-concentration and translocation factors did not exceed “1” and decreased with application of either PB or CMPB. In conclusion, enriching biochar with cow manure is a recommended strategy to reduce Cd uptake and translocation to straw and seeds. Moreover, Concentrations of Cd did not exceed the permissible levels in grains when soils amended with the highest rate of CMPB.

Quantitative Assessment of the Safety Benefits Associated with Increasing Clinical Peanut Thresholds Through Immunotherapy

Peanut immunotherapy studies are conducted with the aim to decrease the sensitivity of patients to peanut exposure with the outcome evaluated by testing the threshold for allergic response in a double-blind placebo-controlled food challenge. The clinical relevance of increasing this threshold is not well characterized. We aimed to quantify the clinical benefit of an increased threshold for peanut-allergic patients. Quantitative risk assessment was performed by matching modeled exposure to peanut protein with individual threshold levels. Exposure was modeled by pairing US consumption data for various food product categories with potential contamination levels of peanut that have been demonstrated to be present on occasion in such food products. Cookies, ice cream, doughnuts/snack cakes, and snack chip mixes were considered in the risk assessment. Increasing the baseline threshold before immunotherapy from 100 mg or less peanut protein to 300 mg peanut protein postimmunotherapy reduces the risk of experiencing an allergic reaction by more than 95% for all 4 food product categories that may contain trace levels of peanut residue. Further increase in the threshold to 1000 mg of peanut protein had an additional quantitative benefit in risk reduction for all patients reacting to 300 mg or less at baseline. We conclude that achieving thresholds of 300mg and 1000 mg of peanut protein by peanut immunotherapy is clinically relevant, and that the risk for peanut-allergic patients who have achieved this increased threshold to experience an allergic reaction is reduced in a clinically meaningful way.

Peanut Residue Carbon and Nitrogen Mineralization under Simulated Conventional and Conservation Tillage

Core Ideas Recommendations of 22 to 67 kg N ha−1 credit after peanut are not substantiated. Decomposition of peanut residue in North Carolina and Alabama fit double exponential decay equations. Nitrogen credit to wheat was 14 to 24 kg N ha−1, but to cotton was 2 to 10 kg N ha−1. Nitrogen credits differ by location and placement of residue. Nitrogen credits should be specified to which crop they are applied. Residue management is an important aspect of cropping systems. Availability of plant residue N to succeeding crops depends on N mineralization rates. Cooperative Extension currently recommends 22 to 67 kg N ha−1 credit to subsequent crops following peanut (Arachis hypogaea L.), but these recommendations are not supported in the literature, nor do they specify if the credit is applied to a subsequent winter or spring crop. The objective of this study was to assess N release rates from residues of three peanut cultivars (NC V‐11, GA 02‐C, and ANorden) at two placements (surface and 10‐cm deep) and two locations representing northern and southern extremes of U.S. commercial peanut production (North Carolina and Alabama). Litterbags containing the equivalent of 3.5 Mg ha−1 were placed in a completely randomized design at both locations with four replications and retrieved periodically up to 335 d after application. Results were fit to single or double exponential decay models. Based on empirical models, the N credit to a subsequent winter wheat (Triticum aestivum L.) crop was estimated at 14 to 19 kg N ha−1 when peanut residues were buried after harvest, and 19 to 24 kg N ha−1 when on the soil surface. When N credits were applied to a subsequent cotton (Gossypium hirsutum L.) crop, they were reduced to 2 to 9 kg N ha−1 (buried) and 6 to 10 kg N ha−1 (surface). Current recommendations are higher than the results obtained in this study suggest and warrant re‐examination.

Food Industry Co-streams: Potential Raw Materials for Biodegradable Mulch Film Applications

Vast amounts of co-streams are generated from plant and animal-based food processing industries. Efficient utilization of these co-streams is important from an economic and environmental perspective. Non-utilization or under-utilization of co-streams results in loss of potential revenues, increased disposal cost of these products and environmental pollution. At present, extensive research is taking place around the globe towards recycling of co-streams to generate value-added products. This review evaluates various co-streams from food processing industries as raw materials in developing biodegradable agricultural mulching applications. Among the agriculture-based co-streams, potato peels, tomato peels, carrot residues, apple pomace, coffee residues and peanut residues were reviewed with respect to production amount, composition, film forming components and film forming capabilities. Similarly, selected co-streams from slaughterhouses, poultry and fish processing industries were also reviewed and evaluated for the same purpose.

Sustainability Assessment of the Agricultural and Energy Systems of Senegal

To improve decision-making, sustainability-based approaches to assessment of options and undertakings demand that we move beyond narrowly defined considerations to address the full suite of requirements for progress towards sustainability. This paper reports on a sustainability assessment exercise that originally focused on burning agricultural residues, primarily peanut shells, for cooking applications in Senegal. The scope of assessment had to be expanded to address the agricultural and energy systems of Senegal, when closer examination revealed a complex set of energy and agricultural system interactions that could undermine the anticipated positive effects of initiatives centred primarily on peanut residue cookstoves. The case highlights the need to be open to expanding the scope of assessment to address underlying and/or unexpected issues that cannot be addressed appropriately at the project scale. In particular, the case illustrates how the assessment of an energy system may serve as an entry point into a deeper exploration of the context in which the energy system is embedded. The analysis also illustrates a situation in which different paths that may be followed, each with its own degree of uncertainty, path dependence, feasibility, fairness, cultural sensitivity, trade-off acceptability and possibilities for public judgement of overall desirability.

内生真菌对花生残茬腐解及土壤酚酸含量的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 内生真菌对花生残茬腐解及土壤酚酸含量的影响 DOI: 10.5846/stxb201308132074 作者: 作者单位: 南京师范大学,南京师范大学,南京师范大学,南京师范大学,中国科学院土壤环境与污染修复重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技支撑计划资助项目(2012BAD05B04);国家自然科学基金资助项目(31370507,30970523);江苏省高校自然科学研究重大项目(13KJA180003);南京市科委工程中心创新能力提升项目(201105058) Effects of an endophytic fungus on decay of peanut residues and phenolic acid concentrations in soil Author: Affiliation: Nanjing Normal University,Nanjing Normal University,Nanjing Normal University,Nanjing Normal University,Key Laboratory of Soil Environment and Pollution Remediation,Institute of Soil Science,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤中花生残茬是导致连作障碍的原因之一。为了探讨施加内生真菌Phomopsis liquidambari(B3)对加速花生残茬腐解、改善连作花生土壤环境、缓解花生连作障碍的作用及其可能机理,通过向土壤中添加花生(Archis hypogaea)残体,利用盆栽试验探讨了施加B3对花生残茬腐解率、土壤部分酚酸物质和酶活性的影响。结果表明:与CK相比,在萌发期和苗期,添加B3处理显著加快残茬腐解,提高纤维素木质素降解率,增加土壤中对羟基苯甲酸、香草酸和香豆酸的含量;在花生整个生育期,施加B3显著调节了土壤中漆酶、锰过氧化物酶(Manganese peroxidase, MnP)、木质素过氧化物酶(Lignin peroxidase, LiP)和多酚氧化酶(Polyphenol oxidase, PPO)活性的动态变化,这种变化有利于花生残茬快速腐解和酚酸类化感物质的及时转化。开花期之后施加B3处理土壤酚酸含量显著降低,花生荚果增产19.9%。实时定量PCR结果表明内生真菌B3在土壤中30 d内可以被检测,并对复杂多样的酚酸类物质具有广谱高效的降解能力。由此说明,施加内生真菌B3可以显著加快连作土壤中花生残茬腐解,进而通过减少土壤酚酸含量来缓解由残茬腐解引起的连作障碍。 Abstract:Peanut residue in the soil is considered to be an obstacle to peanut replanting. We aimed to understand the effect of applying an endophytic fungus [Phomopsis liquidambari (B3)]on accelerating peanut residue decay, improving the micro-ecological environment in the soil, and alleviating an obstacle to peanut replanting as well as its possible mechanism. We investigated the dynamics of peanut residue decay, phenolic acid concentrations, and enzyme activities during peanut growth in a pot experiment, where peanut residues were added into soil. Results showed that applying endophytic fungus B3 (treatment B3+) significantly accelerated the decay of peanut residue at the peanut germination and seedling stages; the decay rate increased by 12.0%-14.7% and the degradation rate of cellulose and lignin increased by 13.7%-17.8% and 21.2%-26.0%, respectively, compared with controls (CK). From the flowering to maturation stages, the decay rate of peanut residues gradually decreased in treatment B3+, but remained higher than that in CK. In addition, the concentrations of p-hydroxybenzoic acid (4-HBA), vanillic acid (VA), and p-coumaric acid (p-CA) in treatment B3+ were significantly greater than those in CK at the germination and seedling stages. This indicated that application of endophytic fungus B3 significantly promoted the release of phenolic acids during decay of peanut residues before the seedling stage.The concentrations of the three kinds of phenolic acids in CK were much greater than those in treatment B3+ from flowering to maturation stages, which were critical stages for peanut formation and disease control; a high concentration of phenolic acids was harmful to peanut growth. In treatment B3+, the activities of laccase, manganese peroxidase, lignin peroxidase, and polyphenol oxidase were all significantly greater than those in CK at the corresponding peanut growth period, and peanut pod yield increased by 19.9%, compared with CK. Increases in activities of soil enzymes, which were associated with decay of peanut residues in treatment B3+, should be beneficial to decay of peanut residues and accelerate conversion of harmful phenolic acid allelochemicals. However, there was no significant difference in the decay rate of peanut residues, phenolic acids concentrations, enzyme activities, and peanut pod yield between treatment B3 (applying sterilized endophytic fungus B3) and CK, indicating that the availability of the endophytic fungus B3 in soils is important. To further demonstrate the availability of B3 and its role in degradation of phenolic acids, a real-time quantitative polymerase chain reaction technique was used to monitor dynamics of endophytic fungus B3 during peanut growth. The biodegradability of B3 was also investigated in pure culture. The results showed that endophytic fungus B3 could adapt to a non-host environment and survive for about 30 d in soil containing higher amounts of peanut residues under natural conditions after detaching from its host. With 200 mg/L VA and p-CA as the sole carbon source, the degradation rate of VA for 96 h and p-CA for 120 h reached 99% after inoculation with B3, and the biomass of B3 increased gradually with time after inoculation. The results suggested that promoting the rapid degradation of peanut residues and regulating dynamics of phenolic acids should be important mechanisms for B3 to alleviate obstacles in peanut replanting. 参考文献 相似文献 引证文献

Survey of peanut levels in selected Irish food products bearing peanut allergen advisory labels

Peanut allergy affects up to 2% of consumers and is responsible for the majority of fatalities caused by food-induced anaphylaxis. Peanut-containing products must be clearly labelled. Manufacturers are not legally required to label peanut if its inclusion resulted from unintentional cross contact with foods manufactured in the same facility. However, the use of allergen advisory statements alerting consumers of the potential presence of peanut allergen has increased in recent years. In previous studies, the vast majority of foods with precautionary allergen statements did not contain detectable levels of peanut, but no data are available on Irish food products. Thirty-eight food products bearing peanut/nut allergen-related statements were purchased from multiple locations in the Republic of Ireland and analysed for the presence of peanut. Peanut was detected in at least one lot in 5.3% (2 of 38) of the products tested. The doses of peanut detected ranged from 0.14 mg to 0.52 mg per suggested serving size (0.035–0.13 mg peanut protein). No detectable levels of peanut were found in the products that indicated peanut/nuts as a minor ingredient. Quantitative risk assessment, based on the known distribution of individual threshold doses for peanut, indicates that only a very small percentage of the peanut-allergic population would be likely to experience an allergic reaction to those products while the majority of products with advisory labels appear safe for the peanut-allergic population. Food manufacturers should be encouraged to analyse products manufactured in shared facilities and even on shared equipment with peanuts for peanut residues to determine whether sufficient risk exists to warrant the use of advisory labelling. Although it appears that the majority of food products bearing advisory nut statements are in fact free of peanut contamination, advice to peanut allergy sufferers to avoid said foods should continue in Ireland and therefore in the wider European Union.

False Positive Detection of Peanut Residue in Liquid Caramel Coloring Using Commercial ELISA Kits

Initial food industry testing in our laboratory using enzyme-linked immunosorbent assay (ELISA) methods indicated that the darkest caramel color (class IV) unexpectedly contained traces of peanut protein, a potential undeclared allergen issue. Caramel production centers on the heating of sugars, often glucose, under controlled heat and chemical processing conditions with other ingredients including ammonia, sulfite, and/or alkali salts. These ingredients should not contain any traces of peanut residue. We sought to determine the reliability of commercially available peanut allergen ELISA methods for detection of apparent peanut residue in caramel coloring. Caramel color samples of classes I, II, III, and IV were obtained from 2 commercial suppliers and tested using 6 commercially available quantitative and qualitative peanut ELISA kits. Five lots of class IV caramel color were spiked with a known concentration of peanut protein from light roasted peanut flour to assess recovery of peanut residue using a spike and recovery protocol with either 15 ppm or 100 ppm peanut protein on a kit-specific basis. A false positive detection of peanut protein was found in class IV caramel colors with a range of 1.2 to 17.6 parts per million recovered in both spiked and unspiked liquid caramel color samples. ELISA kit spike/recovery results indicate that false negative results might also be obtained if peanut contamination were ever to actually exist in class IV caramel color. Manufacturers of peanut-free products often test all ingredients for peanut allergen residues using commercial ELISA kits. ELISA methods are not reliable for the detection of peanut in class IV caramel ingredients and their use is not recommended with this matrix.

Impact of Thermal Processing on ELISA Detection of Peanut Allergens

This study examined the effect of heat treatment on the solubility of peanut proteins and compared the performances of two commercial ELISA kits (Veratox Quantitative Peanut Allergen Test and BioKits Peanut Assay Kit) for quantitation of peanut residues as affected by different heat treatments (moist and dry heat) and detection targets (mixture of proteins vs specific protein). Both laboratory-prepared and commercial peanut flour preparations were used for the evaluation. The two ELISA kits tended to underestimate the levels of protein in samples that were subjected to elevated heat, respectively, by more than 60- or 400-fold lower for the autoclaved samples and by as much as 70- or 2000-fold lower for the dark-roast commercial flour samples. The BioKits test, which employs antibodies specific to a heat labile protein (Ara h 1), in general exhibited a greater degree of underestimation. These results suggest that commercial ELISA kits may not be able to accurately determine the amount of proteins present in thermally processed foods due to changes in the solubility and immunoreactivity of the target proteins. Users need to be aware of such limitations before applying ELISA kits for evaluation of food allergen control programs.

Persistence of peanut allergen on a table surface

BackgroundA diagnosis of peanut allergy has a major impact on an individual’s quality of life. Exposure to even small amounts of peanut can trigger serious reactions. Common cleaning agents can easily remove peanut allergen from surfaces such as table tops. Parents of children with peanut allergy frequently ask if peanut allergen can persist on surfaces if they have not been cleaned.ObjectivesThe purpose of this study was to determine the persistence of peanut allergen on a typical table surface over time.MethodsFive mL of peanut butter was evenly smeared on a 12 inch by 12 inch (30.5 by 30.5 cm) square on a nonporous (laminated plastic) table surface. Five squares were prepared in the same manner. The table was kept in a regular hospital office at room temperature and ambient lighting. No cleaning occurred for 110 days. Samples were taken at regular intervals from different areas each time. A monoclonal-based ELISA for arachis hypogaea allergen 1 (Ara h 1), range of detection 1.95-2000 ng/mL, was used to assess peanut allergen on the table surface.ResultsAt baseline, there was no detectable Ara h 1 allergen. Immediately post application and for 110 days of collecting, detectable Ara h 1 was found each time a sample was taken. There was no obvious allergen degradation over time. Active cleaning of the contaminated surface with a commercial cleaning wipe resulted in no detectable Ara h 1 allergen.ConclusionsPeanut allergen is very robust. Detectable Ara h 1 was present on the table surface for 110 days. Active cleaning of peanut contaminated surfaces easily removed peanut residue and allergen. Regular cleaning of surfaces before and after eating should be reinforced as a safety measure for all individuals with peanut allergy.

Influence ofVerticillium dahliaeInfested Peanut Residue on Wilt Development in Subsequent Cotton

Texas ranks first in cotton production in the United States and accounts for approximately 40% of the total production. Most of the cotton production is concentrated in the Texas High Plains where cotton and peanut are commonly grown in rotation. With peanut being a legume crop, farmers routinely leave residue on the soil surface to improve soil fertility; however,V. dahliaecan survive in the crop residue contributing inoculum to the soil. A microplot study was conducted to investigate the impact of peanut residue infested withV. dahliaeon subsequent microsclerotia density in soil and Verticillium wilt development in cotton. The effects of infested peanut residue rate on percent germination of cotton seeds and on wilt incidence were monitored in 2008 and 2009. In both years microplots were planted with a susceptible cotton cultivar, Stoneville (ST) 4554B2RF. Increasing infested peanut residue rate was positively correlated with wilt incidence in cotton and negatively correlated with germination of cotton seeds. Density of microsclerotia in the soil increased significantly with increasing rates of infested peanut residue over time. Results indicate infested peanut residue serve as a source ofV. dahliaeinoculum, and removing infested residue can reduce disease development in subsequent cotton crops.