Nguyễn Bảo Lộc * , Nicorescu Irina Orange Nicole

* Tác giả liên hệ (nbloc@ctu.edu.vn)

Abstract

In this work, pulsed light (PL) efficacy was investigated on B. subtilis spores in liquid and dry state (glass marbles and spices). We studied the bacterial suspension in conditions (0.6 J.cm-2/flash) and spices at 1 J.cm-2/flash. In liquid state, only 0.9 log microbial reduction was recorded when 6 J.cm-2 was applied. SEM analysis showed that B. subtilis spores in suspension were not affected by the PL treatment. When DNA extracted from B. subtilis spores was analyzed, no significant difference was found between the control and PL-treated samples. In dry state the destruction level remained below 1 log when a treatment of 10 J.cm-2 was carried out on black pepper and ground caraway, while a 2.8 log microbial reduction was reached for glass marbles. When control and PL-treated B. subtilis spores in dry state were investigated by SEM, no disruption in spore structure was recorded but a significant number of PL-treated spores were flattened.

Keywords: Pulsed light, spices, decontamination, Bacillus subtilis spore

Tóm tắt

Trong nghiên cứu này, hiệu quả diệt khuẩn của xung ánh sáng được đánh giá trên bào tử Bacillus subtilis dạng huyền phù và dạng khô (bào tử vi khuẩn được gây nhiễm trên bi thuỷ tinh và gia vị). Nghiên cứu được thực hiện với cường độ 0,6 J.cm-2/xung trên huyền phù vi sinh vật, và trên gia vị với cường độ 1 J.cm-2/xung. ở dạng huyền phù, với cường độ 6 J.cm-2 chỉ tiêu diệt được 0,9 log bào tử vi khuẩn.Hình ảnh phân tích bằng kính hiển vi điện tử (SEM) cho thấy bào tử B.subtilis ở dạng huyền phù không bị ảnh hưởng bởi xử lý xung ánh sáng. Qua phân tích ADN trích ly từ bào tử B subtilis,không nhận thấy sự khác biệt ý nghĩa giữa mẫu xử lý và mẫu đối chứng. ở dạng khô, mức độ tiêu diệt bào tử B. subtilis đạt được dưới 1 log khi xử lý ở cường độ 10 J.cm-2 trên hạt tiêu và tiểu hồi, trong khi trên bi thuỷ tinh thì mức độ này đạt tới 2,8 log.Khi phân tích hình ảnh bào tử B. subtilis dạng khô của mẫu đối chứng và mẫu xử lý bằng xung ánh sáng qua kính hiển vi điện tử, các bào tử đều không bị phá vỡ bởi xung ánh sáng, tuy nhiên có một số lượng đáng kể bào tử bị thay đổi hình dạng được phát hiện trong mẫu đã xử lý bằng xung ánh sáng.

Từ khóa: xung Ánh sáng, gia vị, khử nhiễm, bào tử B. subtilis

Article Details

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