Use of air-assisted electrostatic spraying system (ESS)or the sprayed lethality in container(SLIC) method to deliver anticmicrobials onto the surface of beef subprimals to ... shiga toxin-producing cells of Escherichia coli

Authors: STELLA, J. MAX - Delaware Valley College; Luchansky, John; MILLER, KELSEY - Ursinus College; Shoyer, Brad; Shane, Laura; MCGEARY, LIANNA - Queens University - United Kingdom; Osorio, Manuela; Stahler, Laura; SEVART, NICHOLAS - Kansas State University; PHEBUS, RANDALL - Kansas State University; THIPPAREDDI, HARSHAVARDHAN - University Of Georgia; Porto-Fett, Anna

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Air-assisted electrostatic spraying (ESS) and the Sprayed Lethality in Container (SLIC) methods, used alone or in combination, offer several advantages over competing technologies (e.g., spraying or dipping) for delivering antimicrobials to food surfaces, notably more uniform coverage, better efficacy, less volume of water and antimicrobial needed, and potential savings in processing time. The objective of this study was to evaluate the efficacy of antimicrobials delivered via ESS and/or SLIC onto the surface of beef subprimals to reduce levels of Shiga toxin-producing cells of Escherichia coli (STEC). Beef subprimals were surface inoculated (lean side; ca. 1 million cells per subprimal) and then surface treated with the following food grade antimicrobials: lauric arginate (LAE; 1%), peroxyacetic acid (PAA; 0.02%), or cetylpyridinium chloride (CPC; 0.4%) via ESS or via SLIC. Subprimals were then vacuum-packaged and stored at refrigeration temperature. One set of subprimals were sampled after an additional 2 h or 3 days of refrigerated storage, whereas another set was retreated with the above antimicrobials (e.g., if treated with antimicrobial 1 on day 0, then on day 3 subprimals were treated with antimicrobial 2 or 3) via SLIC after 3 days of storage and then sampled after 2 h or 4 days of additional refrigeration storage. Our results showed that a single/initial application of antimicrobials via ESS or SLIC resulted in reductions of ca. 2 to 20 cells of STEC per subprimal over 7 days of refrigerated storage. However, when subprimals were initially treated the food with food grade chemicals via ESS or SLIC and then retreated with one of these same antimicrobials via SLIC on day 3, additional reductions of 3 to 10 cells per subprimal in pathogen numbers were observed after an additional 4 days of storage. Application of LAE, PAA, or CPC, alone or in combination, via ESS or SLIC is effective for reducing low levels of STEC on the surface of beef subprimals.

Technical Abstract: We evaluated the efficacy of an air-assisted electrostatic spraying system (ESS) and/or the Sprayed Lethality in Container (SLIC) method to deliver antimicrobials onto the surface of beef subprimals to reduce levels of Shiga toxin-producing Escherichia coli (STEC). Beef subprimals were surface inoculated (lean side; ca. 5.8 log CFU/subprimal) with 2 ml of an eight-strain cocktail comprised of single strains of rifampicin-resistant (100 micro gram/ml) STEC (O111:H, O45:H2, O103:H2, O104:H4, O121:H19, O145:NM, O26:H11, and O157:H7) and then incubated the meat at 4 degrees C for 30 min to allow for bacterial attachment. Next, inoculated subprimals were surface treated with lauric arginate (LAE; 1%), peroxyacetic acid (PAA; 0.02%), or cetylpyridinium chloride (CPC; 0.4%) by passing each subprimal, lean/inoculated side facing upward, through an ESS cabinet or via SLIC. Subprimals were then vacuum-packaged and stored at 4 degrees C. One set of subprimals were sampled after an additional 2 h or 3 days of refrigerated storage, whereas another set was retreated with the above antimicrobials (e.g., if treated with antimicrobial 1 on day 0, then on day 3 subprimals were treated with antimicrobial 2 or 3) via SLIC after 3 days of storage and then sampled after 2 h or 4 days of additional storage at 4 degrees C. Surviving STEC were enumerated using the USDA/ARS package rinse method. Single/initial application of LAE, PAA, or CPC via ESS or SLIC resulted in reductions of ca. 0.3 to 1.3 log CFU/subprimal over 7 days of storage. However, when subprimals were initially treated with LAE, PAA, or CPC via ESS or SLIC and then retreated with one of these same antimicrobials via SLIC on day 3, additional reductions of 0.4 to 1.0 log CFU/subprimal in pathogen numbers were observed after an additional 4 days of storage. Application of LAE, PAA, or CPC, alone or in combination, via ESS or SLIC is effective for reducing low levels of STEC on the surface of beef subprimals.