Widespread consumption of fresh-cut vegetables without cooking results in ingestion of major foodborne pathogens including Bacillus cereus. In this study, we aimed to develop a method to rapidly detect B. cereus in fresh-cut vegetables by combining commercial PCR analysis with enrichment of the pathogenic levels. A mixture of B. cereus strains (KCTC1013, KCTC1014, KCTC1092, KCTC1094, and KCTC3624) was inoculated on the surface of fresh-cut cabbage lettuce (20 g) and baby leafy vegetables (10 g) to concentration 1, 2, 3, 4, and 5 log CFU/g. Eighty milliliters of TSB with 0.15% polymyxin B was used for cabbage lettuce, and 90 mL of medium was used for baby leafy vegetables and incubated at 42oC for 0, 2, 3, 4, 5, 6, and 7 h. One milliliter of the enriched media was plated on mannitol-egg yolk-polymyxin agar for quantification, and another 1 mL was used for DNA extraction for PCR analysis. Additionally, the minimum number of sub-samples to be tested from a pack of fresh-cut vegetable samples was determined using 5 sub-samples. The results from this study showed that for detecting B. cereus in fresh-cut cabbage lettuce, 3, 4, 5, 6, and 7 h enrichment were required to at least detect 5, 4, 3, 2, and 1 log CFU/g of B. cereus, respectively. B. cereus in fresh-cut baby leafy vegetables could be detected after 2, 3, 4, 5, and 6 h of enrichment at 5, 4, 3, 2, and 1 log CFU/g, respectively, using a combination of enrichment and PCR analysis. To determine if a pack of fresh-cut vegetable is positive, the minimum number of sub-samples should be 3. These results can be used to develop a rapid detection method to semi-quantify B. cereus in fresh-cut vegetable samples combining enrichment and PCR.

농업기술을 정보기술과 융합하여 농산물에 대한 in-situ 신속측정기술을 개발하기 위해서는 농업기술과 정보기술에 대한 가교적 컨텐츠(bridging contents)가 요구된다. 사과의 전분 함량은 성숙도 또는 숙성도를 평가하는 주요 지표 중의 하나이다. 사과의 전분 함량을 현장에서 신속히 평가하게 되면 수확 및 저장 관리에 효과적으로 활용할 수 있다. 본 연구에서는 컴퓨터 시각에 의해 사과의 전분 함량을 신속히 평가하는 방법을 고안하고자 먼저 3종의 전분지수를 제안한 후, 총 전분 함량 및 아밀로오스 함량과의 상관관계를 분석하여 전분함량에 대한 전분지수의 검정력을 평가하였다. 분석 결과에 의하면, 전분지수를 HLS(Hue-Lightness-Saturation) 영상으로 전환 후 전체 면적 대비 순청색(pure blue)에 해당하는 면적의 비로 정의할 때 총 전분 함량을 가장 잘 표시하는 것으로 나타났다. 이때 총 전분 함량은 수분 함량의 영향을 배제한 건량 기준으로 표시할 때 전분지수의 검정력이 가장 우수한 것으로 나타났다. 따라서, 본 연구에서 개발한 전분지수 표시법을 정보기술과 접목하면 매우 효과적인 현장 기술로 활용할 수 있을 것으로 기대된다.

The diamondback moth, Plutella xylostella is a one of the most important pests of various cruciferous crops and has a geographically wide ranging habitat. The heavy dependence on chemical pesticides has created severe pesticide resistance problems. In recent years, Bacillus thuringiensis product have been widely used for P. xylostella control bus genetic resistance in populations to some B. thuringiensis strains, compounded by cross-resistance to several different B. thuringiensis toxins, has also been identified. Such recent resistance problems serve to emphasize the urgent need for alternative control agents and their use within an integrated pest management approach. Baculoviruses have been used as agents for the biological control of certain insect pest species. the granuloviruses (GVs), based on the structure of the occluded virus and the occlusion body (OB). Several reports have showed P. xylostella granulovirus (PxGV) as a promise control agent for P. xylostella. However, it is very difficult to study GV because its OB, granule, has very small size and could be observed exactly under the electron microscopy (EM). This study was performed to develop rapid quantification method for granule of PxGV. After the exact quantification of granule with latex beads using EM, the universal extraction method of viral DNA was established for consistent experiment. The number of granules was calculated by the quantification of PCR products for granuline gene using spectrophotometer and densitometer. This novel calculation method for granule would be useful to study GV.