REDUCTION OF AQUEOUS CHLORINE BY ORGANIC MATERIAL

Aqueous chlorine, used to reduce surface bacteria populations on carca sses of slaughter animals after evisceration, during chilling, and aft er transport, dissipates in the presence of organic matter. This study characterized the amount of residual chlorine present when aqueous HO Cl was exposed to bovine serum albumin, bovine lean muscle, porcine ad ipose tissue, or Trypticase soy agar (TSA) surfaces. Test chlorine sol utions, made using Ca (OCl)(2), contained 0, 50, 100, 200, 400, 800, 1 ,600, or 3,200 ppm chlorine, the latter two concentrations being used only in the case of albumin. Chlorine depletion by albumin was almost instantaneous, but was influenced by the amount of albumin present and the initial chlorine concentration. Chlorine exposed to organic surfa ces was reduced most readily by lean muscle, then by TSA, and least by adipose tissue. Available chlorine was reduced by about 62% when the volume of aqueous chlorine was 22 ml/cm(2) of lean muscle and by about 89% when the volume of aqueous chlorine was 0.69 ml/cm(2). With incre asing exposure time, the exposure to lean and fat decreased available chlorine by an average of about 10% in 4 min, 27% in 32 min, and 45% i n 96 min. Thirteen pure bacterial cultures and two mixed cultures asso ciated with meat were exposed to aqueous chlorine to characterize the effectiveness of the chlorine. All cultures except Bacillus cereus and Enterococcus faecalis were destroyed within 15 s by 3 ppm chlorine. B ased on the data, the authors conclude that (a) available chlorine red uction is dependent on exposure time, chlorine concentration, and amou nt/source of organic material and (b) bacterial inactivation by aqueou s chlorine is species specific. These data are of value for estimating chlorine dose for carcass decontamination during washing/chilling and for confirming that bacterial resistance to HOCl is species specific.