厌氧土壤消毒、改良型和灌溉方案影响农业土壤中沙门氏菌的存活和死亡。
Anaerobic soil disinfestation, amendment-type, and irrigation regimen influence Salmonella survival and die-off in agricultural soils.
机构信息
Department of Food Science and Technology, Virginia Tech, Blacksburg, Virginia, USA.
Department of Biostatistics and Computational Biology, University of Rochester, Rochester, New York, USA.
出版信息
J Appl Microbiol. 2022 Mar;132(3):2342-2354. doi: 10.1111/jam.15324. Epub 2021 Oct 26.
AIMS
This study investigated Salmonella concentrations following combinations of horticultural practices including anaerobic soil disinfestation (ASD), soil amendment type and irrigation regimen.
METHODS AND RESULTS
Sandy-loam soil was inoculated with a five-serovar Salmonella cocktail (5.5 ± 0.2 log CFU per gram) and subjected to one of six treatments: (i) no soil amendment, ASD (ASD control), (ii) no soil amendment, no-ASD (non-ASD control) and (iii-vi) soil amended with pelletized poultry litter, rye, rapeseed or hairy vetch with ASD. The effect of irrigation regimen was determined by collecting samples 3 and 7 days after irrigation. Twenty-five-gram soil samples were collected pre-ASD, post-soil saturation (i.e. ASD-process), and at 14 time-points post-ASD, and Salmonella levels enumerated. Log-linear models examined the effect of amendment type and irrigation regimen on Salmonella die-off during and post-ASD. During ASD, Salmonella concentrations significantly decreased in all treatments (range: -0.2 to -2.7 log CFU per gram), albeit the smallest decrease (-0.2 log CFU per gram observed in the pelletized poultry litter) was of negligible magnitude. Salmonella die-off rates varied by amendment with an average post-ASD rate of -0.05 log CFU per gram day (CI = -0.05, -0.04). Salmonella concentrations remained highest over the 42 days post-ASD in pelletized poultry litter, followed by rapeseed, and hairy vetch treatments. Findings suggested ASD was not able to eliminate Salmonella in soil, and certain soil amendments facilitated enhanced Salmonella survival. Salmonella serovar distribution differed by treatment with pelletized poultry litter supporting S. Newport survival, compared with other serovars. Irrigation appeared to assist Salmonella survival with concentrations being 0.14 log CFU per gram (CI = 0.05, 0.23) greater 3 days, compared with 7 days post-irrigation.
CONCLUSIONS
ASD does not eliminate Salmonella in soil, and may in fact, depending on the soil amendment used, facilitate Salmonella survival.
SIGNIFICANCE AND IMPACT OF THE STUDY
Synergistic and antagonistic effects on food safety hazards of implementing horticultural practices should be considered.
目的
本研究调查了园艺措施（包括厌氧土壤消毒（ASD）、土壤改良类型和灌溉方案）组合后沙门氏菌的浓度。
方法与结果
沙壤土中接种了五种沙门氏菌混合菌（每克 5.5±0.2 对数 CFU），并进行了以下六种处理之一：（i）不添加土壤改良剂，ASD（ASD 对照），（ii）不添加土壤改良剂，无 ASD（非 ASD 对照），以及（iii-vi）用颗粒状家禽粪便、黑麦、油菜籽或野豌豆进行土壤改良并进行 ASD。通过在灌溉后 3 天和 7 天收集样本来确定灌溉方案的效果。在 ASD 前、土壤饱和后（即 ASD 过程）和 ASD 后 14 个时间点采集 25 克土壤样本，并对沙门氏菌水平进行计数。对数线性模型研究了改良剂类型和灌溉方案对 ASD 期间和之后沙门氏菌衰减的影响。在 ASD 过程中，所有处理中的沙门氏菌浓度均显著下降（范围：-0.2 至-2.7 对数 CFU 每克），但观察到的最小下降（颗粒状家禽粪便中为-0.2 对数 CFU 每克）可以忽略不计。沙门氏菌衰减率因改良剂而异，平均 ASD 后衰减率为每天-0.05 对数 CFU 每克（CI=0.05，0.04）。在 ASD 后 42 天内，颗粒状家禽粪便中的沙门氏菌浓度仍然最高，其次是油菜籽和野豌豆处理。研究结果表明，ASD 不能完全消除土壤中的沙门氏菌，某些土壤改良剂有助于增强沙门氏菌的存活。沙门氏菌血清型分布因处理而异，颗粒状家禽粪便支持纽波特沙门氏菌的存活，而其他血清型则不然。与灌溉后 7 天相比，灌溉后 3 天，沙门氏菌浓度增加了 0.14 对数 CFU 每克（CI=0.05，0.23）。
结论
ASD 不能完全消除土壤中的沙门氏菌，而且实际上，根据使用的土壤改良剂，可能会促进沙门氏菌的存活。
研究的意义和影响
应该考虑实施园艺措施对食品安全危害的协同和拮抗作用。
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