|Bosilevac, Joseph - Mick|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/11/2011
Publication Date: 3/2/2011
Citation: Bosilevac, J.M., Iwen, P.C. 2011. Sensitivity of Mycobacterium bovis to common beef processing interventions [abstract]. 2011 Beef Safety Summit, Dallas, TX. March 2-4, 2011. 2011 Beef Industry Safety Summit Research Update. Abstract No. 8. Interpretive Summary:
Technical Abstract: Objective. Mycobacterium bovis is the causative agent of bovine tuberculosis, a relevant zoonosis that can spread to humans through inhalation or by ingestion. M. bovis multiplies slowly, so infected animals may be sent to slaughter during the early stages of the disease before diagnosis and when the shedding of M. bovis in oral or respiratory secretions and in feces may occur. Since cattle actively shedding M. bovis may contaminate the beef processing environment, the objective of this study was to evaluate multiple processing interventions and determine which may be the best means to control M. bovis if it is present. Experimental Treatments. Four strains of M. bovis isolated from cattle were evaluated in vitro for their ability to survive when exposed to seven commonly used interventions for 30 s in suspension. Treatments consisted of hot water (HW) at 65 deg, 70 deg, 75 deg, 80 deg, and 85 deg C; lactic acid (LA) at 2 and 5% used at 25 deg and 50 deg C; and at ambient temperature; 500 and 1,200 ppm acidified sodium chlorite (ASC); 50 ppm chlorine (Cl) and commercial products containing either 220 ppm hydrogen peroxide and peroxyacetic acid (POAA), 300 ppm bromine (Br), or a blend of 2% citric, phosphoric and hydrochloric acids (CPH). All effects were measured by most probable number (MPN) determinations and colony forming unit (CFU) counts then compared to the level of M. bovis remaining after control treatments in saline at ambient temperature. Key Results. Treatments with Cl, CPH, and either concentration of LA at ambient temperatures did not reduce the number of M. bovis. However, treatment with either concentration of LA at 50 deg C, POAA, or Br reduced M. bovis by 1.5 to 2 log CFU when compared to the control (P < 0.05). Additionally, both concentrations of ASC and hot-water at greater than or equal to 70 deg C reduced M. bovis by at least 3 log CFU (P < 0.05) when compared to controls. In a timed exposure experiment, HW at 75 deg C showed a reduction in M. bovis at 5 sec. How this Information can be Applied in the Industry. This work has identified common treatment interventions that are most effective at reducing M. bovis viability. Processors can determine which of these interventions best fits their needs to answer any concerns about potential M. bovis contamination in their facilities.