Ultra-high-pressure liquid chromatography–solid-phase clean-up for determining aflatoxins in Egyptian food commodities

In this work, we determined the content of regulated aflatoxins (ATs) B1, B2, G1, and G2 in food commodities using solid-phase extraction (SPE) and ultra-high-pressure liquid chromatography with fluorescence detection without derivatization. We extracted ATs from the ground samples by mixing in NaCl and 80% (v/v) methanol. The sample was enriched and cleaned up by SPE technique using Bakerbond^® C18 cartridges. The extract that we obtained was immediately analyzed using isocratic elution with a mobile phase consisting of acetonitrile, methanol and deionized water in a ratio of 64:18:18. Method validation was carried out by determining these ATs in a quality control material consisting of almond T02445QC and with the add-found test. The results provided satisfactory recovery within the range of 89.6–103.3%. Repeatability and intermediate precisions were assessed as RSD (%) which were found in the range of 1.1–11.3% and 1.5–12.0%, respectively. The limit of detection (S/N = 3) was 0.03, 0.02, 0.04, and 0.02 μg kg⁻¹ for B1, B2, G1 and G2, respectively. Finally, the method was successfully applied to determine ATs in raw Egyptian food commodities, namely maize, popcorn, pistachio, corn, peanuts, chilli, wheat, green coffee and almond, and the corresponding RSD did not exceed 11%.     

河南省市售食品中黄曲霉毒素污染状况分析

目的初步了解河南省市售食品中黄曲霉毒素的污染状况,为进一步完善相关卫生标准和有关部门加强监管提供科学依据。方法从河南省各地市的大型商场、小型超市、农贸市场随机采集米面制品(小麦粉、玉米面、米粉)、食用植物油(花生油、大豆油、玉米油)、坚果(花生、葵花籽、西瓜子)、调味品(酱油、食用醋、辣椒、花椒)等四类食品共862份样品,采用高效液相色谱法测定4种黄曲霉毒素的含量,并对检测结果进行分析。结果862份市售食品中,黄曲霉毒素的综合检出率为44.9%,其中,黄曲霉毒素B1的检出率为41.3%,合格率为92.8%。黄曲霉毒素含量最高的是花生,高达44.8μg/kg。结论市售食品中存在黄曲霉毒素污染的现象,有关部门应引起重视,加强监督管理,以减少其对人民群众健康的影响和危害。     

Peanut consumption and reduced risk of colorectal cancer in women： A prospective study in Taiwan

AIM: To examine whether peanut consumption is associated with a reduced risk of colorectal cancer in a prospective cohort with a 10-year follow-up. METHODS: In 1990-1992, residents (12026 men and 11917 women aged 30 to 65 years) in 7 townships, Taiwan, were interviewed and recruited into a cancer-screening cohort and annually followed up. Colorectal cancer cases in this cohort were identified from cancer registry and death certificates. Incidence rates of this disease by the end of 2001 were calculated by gender for the primary study variable and covariates. The dietary intake was assessed by means of weekly food frequency measures, including frequently consumed food groups and folk dishes including sweet potato, bean products, peanut products, pickled foodstuffs, nitrated or smoked foodstuffs. RESULTS: During the study period, 107 new colorectal cancer cases (68 men and 39 women) were confirmed. The multivariate Cox's proportional hazard model showed that the relative risk (RR) of peanut consumption was 0.73 [95% confidence interval (CI) =0.44-1.21] for men and 0.42 (95% CI =0.21-0.84) for women. However, frequent intake of pickled foodstuffs was harmful for women (RR = 2.15, 95% CI =0.99-4.65). The risk of colorectal cancer was also elevated among cigarette smokers but not significant (P<0.05). CONCLUSION: This study suggests that frequent intake of peanut and its products may reduce colorectal cancer risk in women, demonstrating the anti-proliferating effect of peanut intake.     

Comparative potency of Ara h 1 and Ara h 2 in immunochemical and functional assays of allergenicity

To assess the relative potency of the major peanut allergens, Ara h 1 and Ara h 2, we examined the relative ability of purified proteins to bind IgE on immunoblots, to cross-link allergen specific IgE in an in vitro assay of degranulation based on RBL SX-38 cells, and to bind IgE in the ImmunoCap assay. Sera from 12 highly sensitive, peanut allergic patients were studied in all assays. IgE immunoblots with crude peanut extracts showed binding of IgE to multiple bands including the 63 kDa and 17-19 kDa bands that contain Ara h 1 and Ara h 2, respectively. In the functional assay, Ara h 2 was more potent than Ara h 1 in 11 of 12 sera tested with a median potency that was 52.5-fold more than Ara h 1 (P < 0.005). Contrary to findings with the functional assay, IgE immunoblots with purified Ara h 1 and Ara h 2 showed substantially lighter binding of IgE to Ara h 2 compared with Ara h 1 (P = 0.02). The ImmunoCap assay gave intermediate results with slightly more IgE binding to Ara h 2 than to Ara h 1 (P = 0.005). In conclusion, Ara h 2 is a very potent allergen and is much more potent than Ara h 1 for most sera using an in vitro assay of IgE cross-linking and cell activation. This finding is different from what was predicted based on immunoblots or with the ImmunoCap assay.     

Perforation of Meckel's Diverticulum by a Peanut Presenting as a Mesentery Abscess

Background

Perforation of Meckel''s diverticulum by a foreign body in children is rarely reported and is usually associated with localized or generalized fibropurulent peritonitis.

Case Presentation

The authors encountered such a case in a 4-year-old boy with perforation of Meckel''s diverticulum by a piece of peanut presenting as a mesentery abscess. The diverticulum was wide-based and histology showed a transmural perforation at the tip of the diverticulum.

Conclusion

Local inflammation due to irritation of the foreign body and progressive pressure necrosis at the tip of the diverticulum may be the pathogenesis of mesentery abscess. A search of the English literature did not reveal any similar case.     

Determination of Aflatoxin B 1 in Highly Contaminated Peanut Samples Using HPLC and ELISA

The precision, accuracy, detection limit and peanut matrix influence of an ELISA were analysed in the determination of aflatoxin B 1 . The assay was performed on two different reference samples: peanut extract and peanut paste, that were spiked with known amounts of aflatoxins. The lower detectable level was 0.5 w g kg -1 . The average intra-assay precision expressed as coefficient of variation (CV) was 11.7% for concentrations between 2.54 and 901 w g kg -1 and the average inter-assay precision was 29.7% for the same range of concentrations. The average accuracy measured by a recovery assay in samples that contained only aflatoxin B 1 was 107%. The correlation between the ELISA and high-performance liquid chromatography (HPLC) applied to 28 peanut samples artificially contaminated with Aspergillus flavus and A. parasiticus spores showed a high correlation ( r = 0.977, P < 0.0001). The detection limits and matrix influence associated with our ELISA procedure were more sensitive than those reported for other ELISA procedures due to specific antiserum treatment.     

大豆、花生中异丙甲草胺残留量检测技术研究

目的:建立大豆、花生中异丙甲草胺残留量的检测技术。方法:采用超声波提取、硅镁吸附剂固相萃取小柱净化样品,毛细管柱气相色谱,电子捕获检测器进行分析。结果:方法的检出限为0.04 mg/kg,回收率为87.0%～98.2%,相对标准偏差为1.82%～5.82%。结论:该方法具有准确度高、精密度好,能够满足大豆、花生中异丙甲草胺残留量的检测要求。