Published online by Cambridge University Press: 01 June 2009
Further studies of immersion cleaning have shown that no deposition of calcium soap and inorganic calcium salts occurs if the immersion solution contains ethylene diamine tetraacetic acid. Compared with results for the previous year there was a marked improvement in the bacteriological state of liners as a result of the absence of calcium deposits. It has also been shown that the addition of tetramethylthiuram disulphide to the rubber mix from which liners are made gives useful bactericidal properties. The intensity of the bactericidal action was little reduced after liners had been in farm use for 4 months.