The Effect of Temperature, Pressure and Chlorine Concentration of Spray Washing Water on Numbers of Bacteria on Lamb Carcases

Abstract

Combined analysis of three experiments showed that when lamb carcases with initial bacterial numbers of between logi103.29 and 4.22/cm2 were spray washed, statistically significant reductions in bacterial numbers of log10O.5 were obtained when the spray wash water temperature was > 57°C, and reductions of log101.0 were obtained when the temperature was ≥ 80°C. Reductions at all temperatures were enhanced by log100.66 when the water contained 30 µg/ml chlorine, but increasing the concentration to 450 µg/ml reduced bacterial numbers only by a further log100–29. At highly contaminated sites increasing the duration of spraying from 30 to 120 s significantly increased the reductions obtained when water containing added chlorine was used. Reductions in bacterial numbers after spray washing with pressures of 3.5, 5.6. 7.7 kg/cm2 were not significantly different.

Reduction of Pathogens Using Hot Water and Lactic Acid on Beef Trimmings

“…Smith and Graham (1978) found that pouring hot water (80 °C) on beef and lamb samples for 10 s destroyed more than 99% of E. coli and Salmonella inoculated (about 10 6.5 /cm 2 ) onto samples. Kelly et al (1981) reported that lamb carcasses sprayed with hot water > 80 °C caused decreases (> 1.0 log 10 /cm 2 ) in aerobic plate counts (APC). Smith (1992) inoculated pieces of brisket (10 cm 2 ) from freshly slaughtered cattle with several strains, including E. coli O157:H7, Listeria monocytogenes, S. typhimurium, and Yersinia enterocolitica (6 log 10 CFU/cm 2 ).…”

Hot‐Water Rinsing and Trimming/Washing of Beef Carcasses to Reduce Physical and Microbiological Contamination

“…They reported that the use of spray-washing with water at 83.5ЊC for 10 or 20 sec resulted in 2.2-log and 3.0-log reductions of bacterial counts, respectively. Similarly, Kelly et al (1981) reported that, as water temperature of spray-washing increased (from 57ЊC to 80ЊC), the bacterial numbers on lamb carcasses following spray-washing decreased (0.05 log/cm 2 to 1.0 log/cm 2 ). Barkate et al (1993) used hot-water washing (95ЊC) to increase the surface temperature of beef carcasses to 82ЊC for 10 sec, which resulted in reductions in bacterial num- bers.…”

Scientific Opinion on the safety and efficacy of using recycled hot water as a decontamination technique for meat carcasses

“…Extensive studies have been carried out on carcass spray treatment in the UK by Bailey (1971), in Ireland by Kelly (1981Kelly ( , 1982, in the USA by Anderson and co-workers on the CAPER system (Anderson et al, 1987), and in Australia by Smith and Davey (Davey, 1988;Davey and Smith, 1989). Together, these studies provide essential information on the parameters that affect the effectiveness of spray treatments.…”

“…A similar manual wash was also evaluated by Kelly et al (1981;1982). Temperature had a far greater effect on reducing bacterial numbers than spray pressures.…”