Department of Environment and Agriculture, Curtin University, Northam, WA, Australia.
Lett Appl Microbiol. 2014 Jan;58(1):16-24. doi: 10.1111/lam.12149. Epub 2013 Sep 20.
Cereal crops grown in the biosolids-amended soil can potentially become contaminated with pathogenic micro-organisms during growth and at the time of harvesting. There is small but unquantified potential risk of transfer of enteric pathogens to humans and animals from contaminated plants and grains. This study examined decay of Escherichia coli, Salmonella enterica serovar Typhimurium and bacteriophage MS2 on the wheat phyllosphere and on stored grains. This was done to assess the health implications of cereal crops contaminated from land application of biosolids. E. coli, S. enterica and MS2 were inoculated onto the leaves, spikelets and grains of wheat. The change in the numbers of inoculated micro-organisms was determined over time to calculate the respective 90% reduction time (T90 ) in each of these environments. A rapid inactivation (T90 <1-3 days) of E. coli and S. enterica and MS2 from the plant phyllosphere was observed, particularly from the spikelets. The decay rates were influenced by micro-organism type and location on the plant phyllosphere. Decay times on the stored grains were longer (T90 9-71 days), with some observed influence of grain variety on pathogen decay times.
Results of this study suggest that there is very limited potential of enteric pathogens survival on wheat phyllosphere and grains. Therefore, the risk of transfer of enteric pathogens from biosolids-amended soil to consumers of grain products is considered to be low. This study has important implications for the grains industry, as the results suggest that chances of preharvest contamination of grains with enteric pathogens from biosolids-amended soil are low.
在生长和收获过程中，生长在生物固体改良土壤中的谷物作物可能会受到致病微生物的污染。受污染的植物和谷物将肠道病原体转移给人类和动物的风险很小，但无法量化。本研究检测了大肠杆菌、肠炎沙门氏菌 Typhimurium 和噬菌体 MS2 在小麦叶际和储存谷物上的衰减情况。这是为了评估受生物固体土地应用污染的谷物对健康的影响。将大肠杆菌、肠炎沙门氏菌和 MS2 接种到小麦叶片、小穗和谷物上。随着时间的推移，确定接种微生物数量的变化，以计算这些环境中各自的 90%减少时间（T90）。在植物叶际观察到大肠杆菌和肠炎沙门氏菌以及 MS2 的快速失活（T90 <1-3 天），尤其是从小穗中。衰减速率受植物叶际上微生物类型和位置的影响。在储存的谷物上的衰减时间更长（T90 9-71 天），观察到谷物品种对病原体衰减时间的一些影响。
本研究的结果表明，肠道病原体在小麦叶际和谷物上的存活潜力非常有限。因此，认为从生物固体改良土壤中转移肠道病原体到谷物产品消费者的风险较低。本研究对谷物行业具有重要意义，因为结果表明，生物固体改良土壤中肠道病原体在前收获期污染谷物的可能性较低。
