Effectiveness of a Laboratory-Scale Vertical Tower Static Chamber Steam Pasteurization Unit against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua on Prerigor Beef Tissue

Abstract

A laboratory-scale vertical tower steam pasteurization unit was evaluated to determine the antimicrobial effectiveness of different exposure times (0, 3, 6, 12, and 15 s) and steam chamber temperatures (82.2, 87.8, 93.3, and 98.9 degrees C) against pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua) inoculated onto prerigor beef tissue. Samples were collected and microbiologically analyzed immediately before and after steam treatment to quantify the effectiveness of each time-temperature combination. The 0-s exposure at all chamber temperatures (cold water spray only, no steam treatment) was the experimental control and provided < or = 0.3 log CFU/cm2 reductions. Chamber temperatures of 82.2 and 87.8 degrees C were ineffective (P > 0.05) at all exposure times. At 93.3 degrees C, significant reductions (> 1.0 log CFU/cm2) were observed at exposure times of > or = 6 s, with 15 s providing approximately 1 log cycle greater reductions than 12 s of exposure. The 98.9 degrees C treatment was consistently the most effective, with exposure times of > or = 9 s resulting in >3.5 log CFU/cm2 reductions for all pathogens.

Effects of steam pasteurisation on Salmonella Typhimurium DT104 and Escherichia coli O157:H7 surface inoculated onto beef, pork and chicken

“…Such reductions are much smaller than previous reports of 3.53 (E. coli O157:H7) and 3.74 log 10 cfu/cm 2 (S. Typhimurium), at a steam/air temperature of 92°C . However, they were greater than those recorded of 0.6 (E. coli O157:H7) and 0.7 log 10 cfu/cm 2 (S. Typhimurium) at 87.8°C, obtained by Retzlaff et al (2004). Possible explanations for these differences have already been discussed above.…”

“…The data obtained in the study at time intervals during 60 s of steam treatment, allows analysis of dynamic changes in bacterial numbers during processing similar to those report by Retzlaff et al (2004). Such data are different from that obtained in previous studies, which estimated bacteria survival after a few, or in some cases, only one treatment period.…”

Food safety management system performance in the lamb chain

“…In a moderate-risk context (overall 2) an average FSMS (overall 2) is expected to be sufficient to realise a good FS output (overall 3), while in a low-risk context (overall 1) even a basic FSMS (overall 1) would be adequate to realise a good FS output (overall 3) (Luning et al, 2008. However, if an unacceptable food safety output (<3) is achieved then in-depth analysis of the FSMS activities in view of the microbiological data and context situation can give insight in possible causes of insufficient performance Sampers et al, 2010).…”

“…Moreover, not all slaughterhouses have a proper supplier relationship and the ability to affect specifications (score 2) and in addition set requirements on the suppliers' FSMS (score 1). Another option is to introduce intervention processes to have the ability to reduce initial levels at carcasses to acceptable levels, such as washing the carcass with hot water or antimicrobial compound (acetic, lactic, peroxyacetic acid, tween 20, cetylpyridinium chloride or nisin) (Calicioglu, Kaspar, Buege, & Luchansky, 2002;Cutter, 1999;Cutter et al, 2000;De Martinez, Ferrer, & Salas, 2002;Dorsa, Cutter, Siragusa, & Koohmaraie, 1996) or the use of steam pasteurization or steam vacuum (Castillo, Lucia, Goodson, Savell, & Acuff, 1999;Nutsch et al, 1998;Retzlaff et al, 2004). However, these techniques should never be used as the primary measure.…”

The anti-microbial effect of a dairy extract (LactiSAL®) on Salmonella enterica Typhimurium and Escherichia coli O157:H7 on different beef carcass surfaces

“…Data from the literature reports that the application of various concentrations of lactic and acetic acid sprays can result in reductions in Salmonella ranging from 0.4 to 3.0 log 10 cfu cm À2 (Cutter & Rivera-Betancourt, 2000;Dickson, 1992;Dickson & Kunduru, 1995;Greer & Dilts, 1992) and E. coli O157:H7 from 0.3 to 2.6 log 10 cfu cm À2 (Brackett, Hao, & Doyle, 1994;Cutter & Siragusa, 1994;Gill & Badoni, 2004;Podolak, Zayas, Kastner, & Fung, 1995). It is also reported that hot water washing and steam pasteurisation can result in reductions in both Salmonella and E. coli O157:H7 ranging from 0.5 to 3.8 log 10 cfu cm À2 (Castillo, Lucia, Goodson, Savell, & Acuff, 1998;Phebus et al, 1997;Retzlaff et al, 2004). Recent studies have reported greater reductions being achieved by combining interventions such as hot water and organic acid washing (Castillo, Lucia, Mercado, & Acuff, 2001).…”