三明治組合流程之安全衛生評估及其HACCP系統的CCP點之建立

Abstract

本研究針對市售三明治多為生熟食混合即食食品，易在製作過程及儲存期間受到微生物污染，在進行市售產品衛生調查後，選定一家複合式餐飲店進行製程衛生改善及建立HACCP系統。 首先調查市售三明治之衛生品質，採購台中市生熟食混合18℃恆溫三明治30件及常溫三明治30件檢測總生菌數、大腸桿菌群、大腸桿菌、金黃色葡萄球菌。結果顯示18℃恆溫三明治總生菌數8件不合格，不合格率26.7％，大腸桿菌群5件不合格，不合格率16.7％，大腸桿菌及金黃色葡萄球菌皆呈陰性；常溫三明治總生菌數28件不合格，不合格率93.3％，大腸桿菌群17件不合格，不合格率56.7％，大腸桿菌1件不合格，不合格率3.3％，金黃色葡萄球菌呈陰性。 在評估市售產品檢驗不理想之情況下，選定一家複合式餐飲店進行店家之自製三明治供應流程，探討組合原料初始菌數量，生菜使用次氯酸鈉溶液消毒，製程衛生改善、設定保存條件及建立HACCP系統。研究結果顯示，三明治組合原料火腿切片總生菌數高達4.11 log CFU/g；結球萵苣總生菌數5.89 log CFU/g、大腸桿菌群3.11 log CFU/g，經200 ppm次氯酸鈉清洗消毒20分鐘後，降低2.04及2.07 log CFU/g。小黃瓜總生菌數7.41 log CFU/g、大腸桿菌群3.96 log CFU/g，經200 ppm次氯酸鈉清洗消毒20分鐘後，降低1.93及1.50 log CFU/g，顯示氯液消毒效果佳；在評估殘留餘氯方面，以分光光度計測出結球萵苣0.283 ppm、小黃瓜0.047 ppm，及攜帶型餘氯比色計測出結球萵苣0.32 ppm、小黃瓜0.05 ppm，均符合飲用水水質標準0.2~1.0 ppm。為了解三明治製程衛生狀況進行塗抹試驗，將砧板、刀具、抹布以沸水煮沸五分鐘及人員手部、包裝袋以75％酒精噴灑消毒，總生菌數(log CFU/cm2)由3.28、2.85、3.45、2.43、0降低至未檢出。自製三明治在冷藏環境中(4℃﹐RH＝35％)，於0、2、4、8、12、16、20、24小時檢測總生菌數、大腸桿菌群、大腸桿菌，放置24小時品質仍符合法規標準。然若在高溫高濕環境下(30℃﹐RH＝65％)，於0、2、4、6、8、12小時檢測總生菌數、大腸桿菌群、大腸桿菌，放置4小時後，在衛生改善前及衛生改善後分別檢出大腸桿菌群3.36、3.04 log CFU/g，超過法規標準。 初步評估30℃/65％ RH保存試驗結果不理想，進行第二次製程模式衛生改善流程，改善方法為將火腿切片油煎加熱，以及選用品質新鮮的結球萵苣、小黃瓜。結果顯示30℃/65％ RH，於0、2、4、6、8、10小時檢測總生菌數、大腸桿菌群、大腸桿菌，在衛生改善前及衛生改善後第8小時，分別檢出大腸桿菌群3.11、3.04 log CFU/g，超過法規標準。其結果與第一次衛生改善流程相比，以第二次衛生改善流程製作之三明治，其保存時限可延長至6小時，改善效果成效佳。本研究三明治之CCP點，分別為結球萵苣、小黃瓜之品質、原料之清洗消毒步驟以及成品保存溫度。

Sandwiches are ready-to-eat foods with both cooked and uncooked ingredients, which are easily exposed to microbial contamination during their preparation and storage. After conducting a hygiene investigation of retail items, this study chose a combined eatery outlet to carry out the hygiene improvement plan for sandwich preparation and establishment of critical control points (CCP) for HACCP system. The hygiene quality of thirty commercial sandwich samples with both cooked and uncooked ingredients sold at 18oC and room temperature in retailers, respectively, were examined, including total microbial count, Escherichia coli (E. coli) count, E. coli colony count and Staphylococcus aureus count. The results showed for sandwiches kept at 18oC, eight samples did not qualify the hygiene requirement for total microbial count, implying a failing rate of 26.7%. Furthermore, five samples did not qualify the hygiene requirement for E. coli colony count, implying a failing rate of 16.7%. All samples did not show detectable E. coli and Staphylococcus counts. For sandwiches kept at room temperature, 28 did not qualify the hygiene checks, giving a failing rate of 93.3%. Seventeen sandwiches failed in coliform count, implying a failing rate of 56.7%. One sandwich failed for E. coli count, implying a failing rate of 3.3%. Staphylococcus tests were negative. The hygiene improvement plan was then conducted by disinfection of raw materials and preparation tools, and mandatory personnel hygiene. Raw vegetables were disinfected with sodium chlorate solution. Results showed that prior to hygiene improvement, sliced ham used in the combo-sandwiches had a total microbial count of 4.11 log CFU/g; head lettuce and cucumbers had a total microbial count of 5.89 log CFU/g and 7.41 log CFU/g, and coliform count of 3.11 log CFU/g and 3.96 log CFU/g, respectively. After a disinfecting wash with 200 ppm of sodium chlorate solution for 20 min, the total microbial and coliform counts for head lettuce dropped to 2.04 and 2.07 log CFU/g, respectively; and dropped to 1.93 and 1.50 log CFU/g for total microbial and coliform counts for cucumber, respectively. Such results demonstrated the effectiveness of chlorate disinfection. The residual chlorine determined by spectrophotometer were found to be 0.283 and 0.047 ppm for head lettuce and cucumbers, respectively, and were 0.32 ppm and 0.05 ppm, respectively, while determined by a portable chlorine colorimeter. These results demonstrated that the residual chlorine levels fell within the drinking water quality standards of 0.2~1.0 ppm. Hygiene improvement for sandwich preparation tools was performed by soaking the cutting board, knives and dirt cloth in boiling water for 5 min. Hygiene improvement for workers' hands and wrapping packages were performed by spraying with a disinfecting solution of 75% alcohol. Results showed that the total microbial count ( log CFU/cm2) were reduced from 3.28, 2.85, 3.45, 2.43, 0 to undetectable levels for cutting board, knives, dirt cloth, workers' hands and triangle plastic bag, respectively. When the sandwiches were stored at 4oC/35% RH, the microbial qualities were still within legal limits after 24 hours. However, when the sandwiches were stored at 30oC/65% RH, microbial quality can be maintained only for up to 4 hours storage, as indicated by coliform counts exceeded legal limits (3.36 log CFU/g prior to hygiene improvement and 3.04 log CFU/g after hygiene improvement, respectively). A second hygiene improvement plan was then carried out for sandwich preparation. The improvement plan involved pan-frying of the sliced ham and using higher quality cabbage lettuce and cucumbers. The results showed that under the storage condition of 30oC/65% RH, microbial quality can be extended to up to 8 hours storage, as indicated by coliform counts of 3.11 log CFU/g prior to hygiene improvement and 3.04 log CFU/g after hygiene improvement, respectively, after 8 hours storage. These results indicated that the sandwich shelf-life can be effectively extended by hygiene improvement. The CCP for sandwich preparation include the quality of vegetables, disinfection of head lettuce and cucumber, and the storage temperature.