|WANG, JIAWEI - Jilin University
|LIAO, JIAFEN - Jilin University
|MA, JINHUA - Jilin University
|LYU, GUANGZE - Jilin University
|YANG, XIAOYIN - Jilin University
|Ibekwe, Abasiofiok - Mark
|MA, JINCAI - Jilin University
Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2023
Publication Date: 9/4/2023
Citation: Wang, J., Liao, J., Ma, J., Lyu, G., Yang, X., Ibekwe, A.M., Ma, J. 2023. Persistence of E. coli O157:H7 in Frozen Soils: Role of Freezing Temperature. Science of the Total Environment. 15(17):13249. https://doi.org/10.3390/su151713249.
Interpretive Summary: Seasonal frozen soils are more common globally than permanent frozen soils and are widely distributed in the northern hemisphere. Frozen soils are widely exploited because of their rich mineral resources and abundant water, energy, and gas resources, and are inhabited by most of the world population. The release of potential pathogenic microorganisms trapped in frozen soils during melting process may threaten the health of the local people. In this study, we investigated the persistence of E. coli O157 in frozen soil samples collected from a seasonal frozen zone located in northeastern China. The objectives of this study were to investigate the persistence profile of E. coli O157 in frozen soils and test the effects of different freezing temperature and soil moisture on the persistence of E. coli O157. The results showed that temperature has a major impact on persistence, while moisture content has less effect on survival of E. coli O157. The data obtained in this study may be helpful in formulating measures to reduce related environmental health risks associated with the contamination of crops grown in frozen soils. The results of this research will be used by growers, researchers, FSIS, FDA, and different state agencies that are involved in leafy green production.
Technical Abstract: Due to high pathogenicity and low infection threshold recent studies of E. coli O157:H7 have focused more on its fate in the environment as it relates to public health. The survival of this pathogen in a large variety of environmental media under temperature above 0 °C has been conducted, while its persistence in frozen soils has received less attention. In this study, we collected soils with different texture from seasonal frozen zone in northeast China and investigated the persistence of EcO157 in soils with freezing temperature (–5 °C and–15 °C) and moisture content (30% and 60% water holding capacity, WHC) of the soils. By fitting the survival data with Weibull model, we obtained three parameters, first log reduction time (d in days), survival curve shape parameters (p), and monthly log reduction of EcO157 (MAR, log-gdw-1-mon-1). The results showed that temperature has a major impact on persistence, while moisture content has less effect on survival of EcO157. Further multi-variable analysis revealed that physical and chemical properties (e.g, sand fraction) of soil play an important role in survival. Certain bacterial groups significantly correlated with the survival of EcO157 in frozen soils at–5 ', not for the ones incubated at–15 '. The current study highlights the importance of research on persistence of pathogenic bacteria in seasonal frozen soils.