Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/7/2014
Publication Date: N/A
Technical Abstract: Control of foodborne pathogenic bacteria in agricultural soils is a major concern for vegetable growers. Pathogenic bacteria can enter soil through a variety of vectors including; manure used for fertilizer, contaminated water, animals and farmers. A technology has surfaced in recent years through which waste biomass can be converted into condensable and non-condensable gases and char. This char contains the minerals and carbon of the feed stock, making it not only suitable as a fertilizer but as a method of carbon sequestration. For this experiment, 3 feed stocks were chosen; pelletized hardwood, pelletized switch grass, and switch grass. Char was produced by pyrolysis at 500° deg C for <1 second (fast) or 1 hour (slow). Soil used was a mixture of soil, sand, vermiculite and turface in a ratio of 0.75:1:1:0.75 (SSVT). 100 grams of SSVT was inoculated with 6 ml of a cocktail consisting of either S. enterica or E. coli O157:H7. After inoculation, char was added to the SSVT at application rates of 1, 3 or 5%. SSVT, inoculum and char were thoroughly mixed by hand for 30 seconds. A 1 gram sample was taken immediately following mixing and then every 2 weeks for a total of 12 sampling times. At the initial sampling there was a 1 log decrease in Salmonella caused by the switch grass pellet slow pyrolysis char (P=0.0061) and a 2 log decrease in E. coli (P=0.0483). At subsequent sampling times significant decreases in both Salmonella and E. coli caused by all pyrolysis chars (P<0.05). These results indicate a strong potential for pyrolysis char as a soil amendment in regard to reduction of S. enterica and E. coli in agriculture type soils. Further research is needed to determine the effects of pyrolysis char on plant growth and pathogenic bacteria.