|STELLA, J. MAX - Delaware Valley College|
|SEVART, NICHOLAS - Kansas State University|
|PHEBUS, RANDALL - Kansas State University|
|THIPPAREDDI, HARSHAVARDAN - University Of Nebraska|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/8/2015
Publication Date: 6/4/2015
Citation: Stella, J., Luchansky, J.B., Shoyer, B.A., Shane, L.E., Osoria, M., Sevart, N.J., Phebus, R.K., Thippareddi, H., Porto Fett, A.C. 2015. Effect of antimicrobials applied on the surface of beef subprimals via an air-assisted electrostatic spraying system(ESS)or the Sprayed Lethality in Container(SLIC)method to control Shiga toxin-producing cells of Escherichia. Meeting Abstract. Volume (1) Page 1; STEC CAP Annual Meeting, Manhattan, KS; June 4-5, 2015.
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 cells of Escherichia coli (STEC). In brief, beef subprimals were surface inoculated (lean side; ca. 5.5 log CFU/subprimal) with 2 ml of an eight strain cocktail comprised of single strains of rifampicin-resistant (100 µg/ml) STEC (STEC-8; O111:H, O45:H2, O103:H2, O104:H4, O121:H19, O145:NM, O26:H11, and O157:H7) and then were incubated at 4 degrees C for 30 min to allow for bacterial attachment. Next, inoculated subprimals were surface treated with lauric arginate (LAE; 50 ppm), peroxyacetic acid (PAA; 400 ppm), or cetylpyridinium chloride (CPC; 400 ppm) by passing each subprimal through an ESS cabinet or via SLIC. Subprimals were then vacuum-packaged and stored at 4 degrees C for up 7 days. One set of subprimals was sampled after 2 h and after 3 and 7 days of storage. Another set of subprimals was retreated with the above mentioned antimicrobials via SLIC after 3 days of storage and then sampled after 2 h or 4 days of additional storage at 4 degrees C. More specifically, if treated with antimicrobial 1 on day 0, then on day 3 subprimals were treated with antimicrobials 2 and 3. Surviving STEC-8 were enumerated using the USDA/ARS package rinse method. A total of 100 µL of the resulting rinse fluid (ca. 50 ml total rinsate) or dilutions thereof were direct plated onto Sorbitol MacConkey agar plates plus rifampicin (100 µg/ml) and incubated for 48 h at 37 degrees C. Pathogen numbers were expressed as log CFU/subprimal. The results revealed that single/initial application of LAE, PAA, or CPC via ESS or SLIC resulted in reductions of ca. 0.6 to 2.0 log CFU/subprimals over 7 days of storage at 4 degrees C. However, when subprimals were initially treated with LAE, PAA, or CPC via ESS or SLIC and then retreated with the same antimicrobials via SLIC on day 3, additional reductions of 0.1 to 1.6 log CFU/subprimals in pathogen numbers were observed after an additional 4 days of storage at 4 degrees C. Thus, 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.