Survival of Salmonella enteritidis and Salmonella typhimurium in chicken manure at different levels of water activity

Survival of Salmonella enteritidis and Salmonella typhimurium in chicken manure at different levels of water activity (a(w)) was determined. The a(w), was adjusted by means of saturated salts with defined equilibrium relative humidity and the manure samples were stored aerobically at 20 degrees C. At a(w), levels higher than 0.93, a moderate increase in colony-forming units over 8-9 h was found for both strains; at a(w) levels of 0.89-0.75, there was a thousand-fold reduction. Extended storage resulted in a million-fold reduction of Salmonella enteritidis in 8 days at an a(w) of 0.89. At higher and lower levels of a(w), the reduction was less extensive. (C) 1999 Published by Elsevier Science B.V. All rights reserved.