The influence of temperature and moisture on the disinfecting activity of methyl bromide on infected poultry litter.

Abstract

ABSTRACT.At 25°, exposure of finely sieved poultry house litter for 20 h to methyl bromide (MeBr) gas at concentrations of 10–120 mg/l, i.e. concentration‐time (CT) products of 200–2400 mg h/l, resulted in a marked reduction in the number of bacteria present in terms of Salmonella typhimurium, Escherichia coli and micrococci. The activity of the gas was affected adversely by a reduction in temperature and by its application to litter of a high moisture content. Except with wet litter, a reduction of >99% of the Salm. typhimurium present resulted from exposure at 25° to gas concentrations as low as 10 mg/l (CT product, 200 mg h/l) and it was undetected in samples exposed to 40 mg/l at 25° (CT product, 800 mg h/l) or 80 mg/l at 10° (CT product, 1600 mg h/l). The significance of reductions of this order, in terms of the infectivity of the litter to chicks subsequently reared on it, is discussed. Escherichia Coli showed a susceptibility similar to that of Salm. typhimurium but micrococci were considerably more resistant.