台灣天然和再製乾酪之衛生品質和組織胺生成乳酸桿菌之分析   全文下載

Hygienic Quality and Incidence of Histamine-forming Lactobacillus Species in Natural and Processed Cheese in Taiwan

本研究係自超級市場採集31 件天然乾酪與39 件再製乾酪樣品，分別分析其中之組織胺相關衛生品質與細菌含量。在微生物品質方面，天然乾酪樣品中之總生菌數與大腸桿菌群含量範圍分別為＜ 1至6.84 log CFU/g 以及＜ 3至60 MPN/g ，再製乾酪樣品之總生菌數與大腸桿菌群含量範圍分別為＜ 1至4.57 log CFU/g 以及＜3至30 MPN/g，而在所有乾酪樣品中並未檢出大腸桿菌（E. coli）。在天然乾酪與再製乾酪樣品中，各有2 件樣品之大腸桿菌群含量超過食品衛生標準的10 MPN/g。其次，雖然天然乾酪樣品中之組織胺平均含量為7.9 mg/100 g ，其中有17 件（54.8%）樣品組織胺含量超過美國FDA規定的鯖科魚類產品之限量標準5 mg/100 g ，而再製乾酪則僅有6 件（15.4%）樣品之組織胺含量超過5 mg/100 g ；在所有乾酪樣品中，其他8 種生物胺之平均含量均小於2 mg/100g 。另外，從天然乾酪中分離出37 株可疑之組織胺生產菌菌落，其中有15 株菌於添加0.25% L-histidine 之MRS broth中培養，分別具有產生6.4 ppm 至16.4 ppm 組織胺之能力，並經鑑定均為乳酸菌（Lactobacillus spp.）。有7 株菌屬於L. brevis ，而有一株L. brevis 亦可產生高達71.2 ppm 之酪胺（tyramine）。

Thirty-one natural cheese and 39 processed cheese products were collected from food markets in Taiwan and analyzed for bacterial content and histamine-related quality. The natural cheese samples had <1 to 6.84 log colony forming unit (CFU)/g of aerobic plate count (APC) and <3 to 60 most probable number (MPN)/g of total coliform (TC). On the other hand, the processed cheese products had <1 to 4.57 log CFU/g of APC and <3 to 30 MPN/g of TC. None of the tested samples contained Escherichia coli. Only 2 of the natural cheese and 2 of the processed cheese products contained more than 10 MPN/g of TC, which is beyond the regulatory limit of hygienic quality. The tested natural cheese products had an average histamine content of 7.9 mg/100 g, while 17 of them (54.8%) had histamine content greater than the 5 mg/100 g limit set by the U.S. Food and Drug Administration for scombroid fish and/or product. In contrast, only 6 processed cheese products (15.4%) had histamine levels greater than this limit. The average content of the other 8 biogenic amines in all tested samples was lower than 2 mg/100 g. Among the 37 presumptive histamine-forming bacterial colonies isolated from the natural cheese products, 15 produced histamine, ranging from 6.4 to 16.4 ppm, in MRS broth supplemented with 0.25% L-histidine. These histamine-producing bacteria were identified as Lactobacillus spp. Of the 7 L. brevis identified, one produced 71.2 ppm of tyramine in histidine-supplemented MRS broth.