在亞熱帶生產低硝酸鹽蔬菜－主婦聯盟生活消費合作社檢驗資料之分析

Abstract

蔬菜中硝酸離子含量對人體健康的危害，已受許多國家關切並進行檢討。本文研究主婦聯盟生活消費合作社在1998~2005年之間，檢驗其共同購買中蔬菜之硝酸離子含量記錄，另外調查台北市零售市場之蔬菜硝酸離子含量，以了解目前國內之情形。 調查台北市零售市場蔬菜硝酸離子含量之結果，以葉菜類最高，除甘藍外，其餘皆在2000 mg NO3–/kg f.w.以上，且最高者為紅莧菜，平均達6650 mg NO3–/kg f.w.；根莖類以球莖甘藍、蘿蔔明顯偏高，其餘低於700 mg NO3–/kg f.w.；花果類皆低於1000 mg NO3–/kg f.w.，其中以青花菜較高。 而主婦聯盟生活消費合作社為有效降低蔬菜硝酸離子含量，除了實施蔬菜硝酸離子限量策略，以維護消費者健康，同時也教導生產者控制硝酸離子之栽培要領，及採收前先自行檢測，如此可明顯降低蔬菜硝酸離子含量，以符合主婦聯盟生活消費合作社再次檢驗之標準。目前主婦聯盟生活消費合作社對於降低蔬菜硝酸離子含量已有極佳的成效，如全部葉菜類的硝酸離子平均含量都已控制在2000 mg /kg f.w.以內，且每年記錄中更有低於100 mg /kg f.w.者。至於根莖類及花果類除蘿蔔、球莖甘藍與青花菜外，相較於零售市場調查之結果則差異不大，且其差異程度皆明顯低於葉菜類。此結果顯見市售之葉菜類仍有降低空間。 因此經由比較主婦聯盟生活消費合作社與台北市零售市場之結果，顯示即使是容易累積硝酸離子的蔬菜種類，或是因天候不佳導致過量硝酸離子累積，皆可經由適當栽培方法及人為的監控，在亞熱帶氣候區的台灣合理降低蔬菜硝酸離子含量。

The potential risk assessment of nitrate in vegetables to human health has been well concerned and by developed countries. This research has been conducted to study the test data of nitrate contents in edible parts of vegetables which are monitoned by Homemaker’s Union Comsumers Cooperative (HUCC) during 1998~2005. In the meantime, a survey of nitrate contents in vegetables purchased from Taipei traditional markets has been also carried out to compare with those of HUCC. Leafy vegetables tend to accumulate higher levels of nitrate than stem, root, flower, and fruit vegetables. The average nitrate contents of leafy vegetables are above 2000 mg NO3–/kg f.w. besides Cabbage in the samples purchased from Taipei traditional markets. Amaranth contained the highest nitrate content with an average of 6650 mg /kg f.w. Stem and root vegetables contained nitrate than less than 700 mg /kg f.w., except kohlrabi and radish. All the nitrate contents of flower and fruit vegetables were less than 1000 mg NO3–/kg f.w. while broccoli ranged the highest in this group. HUCC set the nitrate maximum levels for vegetables and also gave growers the instruction for controlling and testing nitrate content before harvest. After the application and efforts, nitrate content of vegetables had been level down apparently and were to agreeable by HUCC. So far the aim of producing low nitrate containiging vegetables has been achieved. The average nitrate contents of leafy vegetables have been controlled under 2000 mg /kg f.w., some samples were even tested less than 100 mg /kg f.w. The nitrate contents in stem, root, flower and fruit vegetables showed little differences between the samples of HUCC and Taipei traditional markets. In general, radish, kohlrabi and broccoli were containing less nitrate than leafy vegetables. Efforts could be made to low down the nitrate contents of leafy vegetables on the traditional markets. If could be expected that, we could reduce nitrate levels in the vegetables by means of cultural management under our subtropical climate conditions.