Kumar Govindaraj Dev, Williams Robert C, Al Qublan Hamzeh M, Sriranganathan Nammalwar, Boyer Renee R, Eifert Joseph D
Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Int J Food Microbiol. 2017 Feb 21;243:90-95. doi: 10.1016/j.ijfoodmicro.2016.12.006. Epub 2016 Dec 14.
The presence of dust is ubiquitous in the produce growing environment and its deposition on edible crops could occur. The potential of wind-distributed soil particulate to serve as a vehicle for S. Newport transfer to tomato blossoms and consequently, to fruits, was explored. Blossoms were challenged with previously autoclaved soil containing S. Newport (9.39log CFU/g) by brushing and airborne transfer. One hundred percent of blossoms brushed with S. Newport-contaminated soil tested positive for presence of the pathogen one week after contact (P<0.0001). Compressed air was used to simulate wind currents and direct soil particulates towards blossoms. Airborne soil particulates resulted in contamination of 29% of the blossoms with S. Newport one week after contact. Biophotonic imaging of blossoms post-contact with bioluminescent S. Newport-contaminated airborne soil particulates revealed transfer of the pathogen on petal, stamen and pedicel structures. Both fruits and calyxes that developed from blossoms contaminated with airborne soil particulates were positive for presence of S. Newport in both fruit (66.6%) and calyx (77.7%). Presence of S. Newport in surface-sterilized fruit and calyx tissue tested indicated internalization of the pathogen. These results show that airborne soil particulates could serve as a vehicle for Salmonella. Hence, Salmonella contaminated dust and soil particulate dispersion could contribute to pathogen contamination of fruit, indicating an omnipresent yet relatively unexplored contamination route.
在农产品种植环境中，灰尘无处不在，且可能沉积在可食用作物上。本研究探讨了风力传播的土壤颗粒物作为鼠伤寒沙门氏菌载体转移至番茄花朵进而转移至果实的可能性。通过刷涂和空气传播的方式，用先前经高压灭菌且含有鼠伤寒沙门氏菌（9.39log CFU/g）的土壤对花朵进行接种。用受鼠伤寒沙门氏菌污染的土壤刷涂的花朵，在接触一周后，100%检测到该病原体呈阳性（P<0.0001）。使用压缩空气模拟气流，将土壤颗粒物吹向花朵。接触一周后，空气传播的土壤颗粒物导致29%的花朵被鼠伤寒沙门氏菌污染。对接触生物发光的受鼠伤寒沙门氏菌污染的空气传播土壤颗粒物后的花朵进行生物光子成像，结果显示病原体转移到了花瓣、雄蕊和花梗结构上。由受空气传播土壤颗粒物污染的花朵发育而来的果实和花萼，果实（66.6%）和花萼（77.7%）中鼠伤寒沙门氏菌检测均呈阳性。对经表面消毒的果实和花萼组织检测发现鼠伤寒沙门氏菌的存在，表明病原体已内化。这些结果表明，空气传播的土壤颗粒物可能是沙门氏菌的载体。因此，受沙门氏菌污染的灰尘和土壤颗粒物扩散可能导致果实受到病原体污染，这表明存在一条普遍存在但尚未得到充分探索的污染途径。
