The growth potential of Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes in dairy manure-based compost in a greenhouse setting under different seasons.
OBJECTIVE
The pathogen growth in dairy compost was studied in a greenhouse setting under different seasons.


RESULTS
The five-strain mixtures of each Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes were inoculated separately into dry compost to yield c.1 log CFU g(-1) . After acclimation at room temperature, the inoculated compost was initially adjusted to moisture levels of 10-50% and then kept in a greenhouse under different seasons. The populations of all three pathogens increased by 2·1-3·9log CFU g(-1) within 3 days in autoclaved compost with initial moisture content of at least 40%. Listeria monocytogenes multiplied up to 2·4 log CFU g(-1) in compost with initial moisture content of 30% and was detected up to 28 days for all seasons, whereas populations of both E. coli O157:H7 and Salmonella increased by c. 1 log in compost with initial moisture content of 30% during winter months only. No pathogen growth in nonautoclaved compost was detected.


CONCLUSIONS
Bacterial species, temperature, light intensity and moisture content affected the growth potential and survival of pathogens in compost when the population of background microflora was low.


CONCLUSIONS
Keeping compost as dry as possible and maintaining certain levels of background microflora may be critical to prevent the growth of pathogens.
Kim
J
J
Department of Food Science and Human Nutrition, Clemson University, Clemson, SC, USA.
Jiang
X
X
D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003612:Dairying; D019453:Escherichia coli O157 / Q000254:growth & development*; D008027:Light; D008089:Listeria monocytogenes / Q000254:growth & development*; D008372:Manure / Q000382:microbiology*; D012475:Salmonella / Q000254:growth & development*; D012621:Seasons; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature; D014867:Water
D008372:Manure; D012987:Soil; D014867:Water