Generation of food-based chlorination disinfection byproducts (F-DBPs) during food processing

据估计，美国每年有7600万人因食物而患病，因此用含有高剂量氯消毒剂的洗涤水冲洗农产品变得越来越重要。然而，氯可以与农产品中的生物分子反应，形成可能致癌的氯化副产物。这项研究将确定这些氯化副产品，重点是那些留在产品中，直到消费者食用。这项研究将量化生菜、胡萝卜、西红柿、苹果和鸡肉在农产品包装设施使用的条件下用含氯洗涤水处理时形成的副产品。 这项研究的成功完成将产生可用于制定控制食源性疾病同时最大限度地降低癌症风险的氯剂量指南的结果。研究结果还将有助于维持对那些担心食品中这些潜在致癌副产品的国家的农产品出口。与受污染农产品有关的食源性疫情凸显了加工设施中食品消毒的重要性。然而，已知氯与有机物质反应产生卤化消毒副产物（DBPs），其通常是有毒的，甚至是致癌的。食品加工过程中氯化DBP的形成可能比饮用水中更重要，因为食品加工可能涉及100倍高水平的氯（约300 mg/L）和有机前体。 虽然目前食品安全的重点是病原体，但这种益处必须与DBP形成的潜在健康影响相平衡。本研究的目的是表征食品中产生的消毒副产物，这些消毒副产物是由氯与氨基酸酪氨酸和色氨酸以及不饱和脂肪酸反应产生的;食品中四种主要生物分子组中的两种与氯高度反应。这项研究的中心假设是，氯化最初将形成卤代酪氨酸，色氨酸和脂肪酸卤代醇生物分子，可溶性副产物可以在长时间氯化过程中释放。与饮用水氯化（天）相比，食物洗涤的较短氯接触时间（~15分钟）将有利于这些初始基于生物分子的副产物相对于可溶性副产物的较高产率。核心假设的推论是，生物分子为基础的副产品将留在食物中，而可溶性副产品将分配到洗涤水中。这些将通过比较各种系统中可溶性副产物和初始基于生物分子的氯化副产物的产率进行测试，包括：1）模型蛋白质和甘油三酯，2）在与食品消毒相关的条件下处理的生菜，胡萝卜，西红柿，苹果和鸡，以及3）从食品洗涤设施收集的样品。将测定基于氨基酸和脂肪酸的副产物的细胞毒性效力，并将其用于标准化食品中这些副产物的测量浓度，以与先前对饮用水中DBP毒性的评价进行比较。这项研究对社会的好处包括通过支持非洲裔美国研究生的论文研究来扩大STEM的参与，通过REU计划参与代表性不足的少数民族本科生，该奖项反映了NSF的法定使命，并通过评估被认为值得支持使用基金会的知识价值和更广泛的影响审查标准。

With an estimated 76 million illnesses attributable to food per year in the US, rinsing produce with washwater containing high doses of chlorine disinfectant is becoming increasingly important. However, chlorine can react with biomolecules in the produce to form chlorinated byproducts that are potentially cancer-causing. This research will identify these chlorinated byproducts, focusing on those that remain in the produce until eaten by consumers. The research will quantify byproducts formed when lettuce, carrots, tomatoes, apples and chicken are treated with chlorine-containing washwater under conditions used in produce packing facilities. Successful completion of this research will produce results that can be used to develop guidelines for chlorine doses that control foodborne illness while minimizing cancer risk. The results will also help maintain produce exports to countries concerned about these potentially cancer-causing byproducts in food.Foodborne outbreaks linked to contaminated produce have heightened the importance of food disinfection in processing facilities. However, chlorine is known to react with organic matter to produce halogenated disinfection byproducts (DBPs) that are often toxic and even carcinogenic. Chlorinated DBP formation during food processing may be more significant than in drinking water, because food processing can involve 100-fold higher levels of both chlorine (~300 mg/L) and organic precursors. While food safety currently focuses on pathogens, this benefit must be balanced with the potential health impacts of DBP formation. The goal of this research is to characterize DBPs produced in foods from reactions of chlorine with the amino acids tyrosine and tryptophan, and unsaturated fatty acids; two of the four major biomolecular groups in food which are highly reactive with chlorine. The central hypothesis of this research is that chlorination will initially form halogenated tyrosines, tryptophans, and fatty acid halohydrin biomolecules, and soluble byproducts can be released during prolonged chlorination. The shorter chlorine contact times of food washing (~15 min) compared to drinking water chlorination (days) will favor higher yields of these initial biomolecule-based byproducts relative to the soluble byproducts. The corollary to the central hypothesis is that biomolecule-based byproducts will remain in food while soluble byproducts will partition to the washwater. These will be tested by comparing the yields of soluble byproducts and initial biomolecule-based chlorination byproducts in various systems including: 1) model proteins and triglycerides, 2) lettuce, carrots, tomatoes, apples, and chickens treated under conditions relevant to food disinfection, and 3) samples collected from food washing facilities. The cytotoxic potencies of the amino acid- and fatty acid-based byproducts will be determined and used to normalize measured concentrations of these byproducts in foods for comparison to previous evaluations of DBP toxicity in drinking water. Benefits to society resulting from this research include broadening participation in STEM through support of the dissertation research of an African American graduate student, engagement of under-represented minority undergraduates through an REU program, and the involvement of a high school science teacher and underrepresented high school students in summer research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.