title: Inactivation of E. coli O157:H7 in cultivable soil by fast and slow pyrolysis-generated biochar.
abstract: An exploratory study was performed to determine the influence of fast pyrolysis (FP) and slow pyrolysis (SP) biochars on enterohemorrhagic Escherichia coli O157:H7 (EHEC) in soil. Soil + EHEC (inoculated at 7 log colony-forming units [CFU]/g of soil) + 1 of 12 types of biochar (10% total weight:weight in soil) was stored at 22°C and sampled for 8 weeks. FP switchgrass and FP horse litter biochars inactivated 2.8 and 2.1 log CFU/g more EHEC than no-biochar soils by day 14. EHEC was undetectable by surface plating at weeks 4 and 5 in standard FP switchgrass, FP oak, and FP switchgrass pellet biochars. Conversely, EHEC populations in no-biochar control samples remained as high as 5.8 and 4.0 log CFU/g at weeks 4 and 5, respectively. Additionally, three more SP hardwood pellet biochars (generated at 500°C for 1 h, or 2 h, or generated at 700°C for 30 min) inactivated greater numbers of EHEC than did the no-biochar control samples during weeks 4 and 5. These results suggest that biochar can inactivate E. coli O157:H7 in cultivable soil, which might mitigate risks associated with EHEC contamination on fresh produce.
authors: 1 Food Safety and Intervention Technologies Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center , Wyndmoor, Pennsylvania.
authors: Joshua B
authors: JB
authors: Gurtler
authors: Akwasi A
authors: AA
authors: Boateng
authors: Yanxue Helen
authors: YH
authors: Han
authors: David D
authors: DD
authors: Douds
mesh_terms: D000818:Animals; D002606:Charcoal / Q000494:pharmacology*; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D006736:Horses; D006801:Humans; D008897:Panicum; D029963:Quercus; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature; D014934:Wood
chemical_list: D012987:Soil; C540010:biochar; D002606:Charcoal