市售虱目魚乾之衛生品質、生物胺含量及組織胺生產菌分離之探討

本研究乃自台灣南部5處市場購買32個虱目魚乾樣品，進行衛生品質、組織胺含量以及組織胺生產菌之分離，以了解市售虱目魚乾之食用安全性。研究結果顯示，22件樣品(68.8%)之揮發性鹽基態氮超過腐敗限量標準(30 mg/100g)；而組織胺含量方面，大部分虱目魚乾樣品(78.1%，25/32) 已超過美國藥物食品管理局(FDA)對水產品中組織胺限量標準5.0 mg/100g，其中有14個樣品(43.7 %)之組織胺含量超過可引發危害作用量 > 50 mg/100g，因此食用這些虱目魚乾可能會導致組織胺中毒。另外，從樣品中分離出30株組織胺生產菌，經以PCR法增幅菌株之16S rDNA序列分析鑑定，其中22株為低產量組織胺生產菌－Staphylococcus xylosus (10株)、S. sciuri (1株)、Bacillus thuringiensis (2株)、Citrobacter freundii (5株)、Klebsiella pneumoniae (1株) 與 E. cloacae (3株)，其他8株為高產量組織胺生產菌(於含1% Histidine之TSB培養液中可產生＞500 ppm之Histamine)－Enterobacter aerogenes (7株)與Citrobacter sp. (1株)。

關鍵字

組織胺；虱目魚乾；組織胺生產菌；品質

並列摘要

Thirty-two dried milkfish products sold in five retail markets in southern Taiwan were purchased and tested to determine the occurrence of histamine and histamine-forming bacteria. This study showed that the TVBN content in 22 samples (68.8%) exceeded the 30 mg/100g decomposition limit. Most of the tested dried milkfish products (78.1%, 25/32) had histamine levels greater than the FDA guideline of 5 mg/100g for scombroid fish and/or product, while fourteen of them (43.7 %) contained > 50 mg/100g hazard action level. Thirty histamine-producing bacterial strains were isolated from samples and identified by 16S rDNA sequencing with PCR amplification. While the bacterial isolates of Staphylococcus xylosus (ten strains), S. sciuri (one strain), Bacillus thuringiensis (two strains), Citrobacter freundii (five strains), Klebsiella pneumoniae (one strain) and E. cloacae (three strains) were identified to be weak histamine-formers, the Enterobacter aerogenes (seven strains) and Citrobacter sp. (one strain) isolates were proven to be prolific histamine-formers with ability to produce >500 ppm histamine in TSBH medium.