Stella J Max, Luchansky John B, Miller Kelsey, Shoyer Bradley A, Shane Laura E, McGeary Lianna, Osoria Manuela, Stahler Laura J, Sevart Nicholas J, Phebus Randall K, Thippareddi Harshavardhan, Porto-Fett Anna C S
1 Delaware Valley University, Doylestown, Pennsylvania 18901.
2 U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038.
J Food Prot. 2017 Aug;80(8):1393-1400. doi: 10.4315/0362-028X.JFP-16-406.
The efficacy of an electrostatic spraying system (ESS) and/or the sprayed lethality in container (SLIC) method to deliver antimicrobial agents onto the surface of beef subprimals to reduce levels of Shiga toxin-producing Escherichia coli (STEC) was evaluated. Beef subprimals were surface inoculated (lean side; ca. 5.8 log CFU per subprimal) with 2 mL of an eight-strain cocktail comprising single strains of rifampin-resistant (100 μg/mL) STEC (O26:H11, O45:H2, O103:H2, O104:H4, O111:H, O121:H19, O145:NM, and O157:H7). Next, inoculated subprimals were surface treated with lauric arginate (LAE; 1%), peroxyacetic acid (PAA; 0.025%), or cetylpyridinium chloride (CPC; 0.4%) by passing each subprimal, with the inoculated lean side facing upward, through an ESS cabinet or via SLIC. Subprimals were then vacuum packaged and stored at 4°C. One set of subprimals was sampled after an additional 2 h, 3 days, or 7 days of refrigerated storage, whereas another set was retreated via SLIC after 3 days of storage with a different one of the three antimicrobial agents (e.g., a subprimal treated with LAE on day 0 was then treated with PAA or CPE on day 3). Retreated subprimals were sampled after 2 h or 4 days of additional storage at 4°C. A single initial application of LAE, PAA, or CPC via ESS or SLIC resulted in STEC reductions of ca. 0.3 to 1.3 log CFU per subprimal after 7 days of storage. However, when subprimals were initially treated with LAE, PAA, or CPC via ESS or SLIC and then separately retreated with a different one of these antimicrobial agents via SLIC on day 3, additional STEC reductions of 0.4 to 1.0 log CFU per subprimal were observed after an additional 4 days of storage. Application of LAE, PAA, or CPC, either alone or in combination, via ESS or SLIC is effective for reducing low levels (ca. 0.3 to 1.6 log CFU) of STEC that may be naturally present on the surface of beef subprimals.
评估了静电喷雾系统（ESS）和/或容器内喷雾致死率（SLIC）方法将抗菌剂输送到牛肉分割肉块表面以降低产志贺毒素大肠杆菌（STEC）水平的效果。将牛肉分割肉块的瘦肉面（每个分割肉块约5.8 log CFU）表面接种2 mL由8种菌株组成的混合菌液，该混合菌液包含耐利福平（100 μg/mL）的STEC单菌株（O26:H11、O45:H2、O103:H2、O104:H4、O111:H、O121:H19、O145:NM和O157:H7）。接下来，将接种后的分割肉块，接种的瘦肉面朝上，通过ESS柜体或采用SLIC方法，用月桂酰精氨酸乙酯（LAE；1%）、过氧乙酸（PAA；0.025%）或十六烷基氯化吡啶（CPC；0.4%）进行表面处理。然后将分割肉块真空包装并在4°C下储存。一组分割肉块在冷藏储存额外2小时、3天或7天后取样，而另一组在储存3天后用三种抗菌剂中的另一种通过SLIC进行再处理（例如，在第0天用LAE处理的分割肉块在第3天用PAA或CPE处理）。再处理后的分割肉块在4°C下额外储存2小时或4天后取样。通过ESS或SLIC单次初始施用LAE、PAA或CPC，在储存7天后导致每个分割肉块的STEC减少约0.3至1.3 log CFU。然而，当分割肉块最初通过ESS或SLIC用LAE、PAA或CPC处理，然后在第3天通过SLIC分别用这些抗菌剂中的另一种进行再处理时，在额外储存4天后观察到每个分割肉块的STEC进一步减少0.4至1.0 log CFU。单独或组合通过ESS或SLIC施用LAE、PAA或CPC对于降低牛肉分割肉块表面可能自然存在的低水平（约0.3至1.6 log CFU）STEC是有效的。
