Center for Food Safety, Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA.
Center for Food Safety, Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA.
Int J Food Microbiol. 2015 Aug 17;207:71-6. doi: 10.1016/j.ijfoodmicro.2015.04.041. Epub 2015 May 2.
Freshly harvested Eastern variety cantaloupes (Cucumis melo L. var. reticulatus cv. Athena) were subjected to three different harvest and wash treatments to examine conditions under which the efficacy of the sanitizer, levulinic acid (LV) plus sodium dodecyl sulfate (SDS), could be enhanced to reduce Salmonella contamination. In treatment set one, cantaloupes were spot inoculated with Salmonella enterica serovar Poona (prepared from solid or liquid media cultures) before or after a 1-min dip treatment in LV (2.5, 5.0, 7.5, or 10%) and 2.5% SDS. S. Poona initial populations on rind tissue (4.26-5.04 log CFU/sample) were reduced to detection by enrichment culture when cantaloupes were subsequently exposed to any of the LV/SDS solutions. When S. Poona was introduced after cantaloupes had been dip-treated, greater decreases in pathogen populations at the stem scar were observed when cantaloupes were treated with increasing concentrations of LV. In treatment set two, the response of S. Poona dip-treated with 5% LV/2.5% SDS was compared to a simulated commercial dump tank treatment incorporating 200 ppm chlorine as well as a two-stage treatment employing both the chlorine tank and LV/SDS dip treatments. S. Poona levels (log CFU/sample or # positive by enrichment culture/# analyzed) after treatments were 5.25, 3.07, 7/10, 5/10 (stem scar) and 3.90, 25/40, 28/40, 20/40 (rind) for non-treated, chlorine tank, LV/SDS dip, and tank plus dip treatments, respectively. In treatment set three, freshly harvested cantaloupes were first treated in the field using a needle-free stem scar injection (200 μl, 7.5% LV/1.0% SDS, 60 psi) and a cantaloupe spray (30 ml, 7.5% LV/0.5% SDS). Cantaloupe stem scar and rind tissue were then spot-inoculated with S. Poona using either a liquid or soil-based medium followed by a simulated dump tank treatment incorporating either 200 ppm chlorine or 5% LV/2% SDS. S. Poona inoculated on field-treated cantaloupe rind decreased by 4.7 and 5.31 (liquid) and 3.27 and 3.36 (soil) log CFU/sample after simulated chlorine and LV/SDS tank treatments, respectively. In the case of stem scar tissue, S. Poona populations exhibited a 1.0 log greater reduction when cantaloupes were treated with LV/SDS compared to chlorine in the dump tank (P<0.05). Based on this study, application of multiple hurdles is warranted, as additional decreases in S. Poona populations were obtained when cantaloupes were subjected to a chlorine dump tank followed by a LV/SDS dip treatment.
新鲜收获的东方品种哈密瓜（Cucumis melo L. var. reticulatus cv. Athena）经过三种不同的收获和清洗处理，以研究在这些条件下，消毒剂戊酸（LV）加十二烷基硫酸钠（SDS）的功效可以增强，以减少沙门氏菌污染。在处理组 1 中，哈密瓜在固体或液体培养基培养物中接种沙门氏菌肠炎血清型浦那（Poona）（准备好）后，或在 1 分钟的 LV（2.5、5.0、7.5 或 10%）和 2.5% SDS 浸泡处理后，用 LV/SDS 溶液进行斑点接种。当哈密瓜随后暴露于任何 LV/SDS 溶液中时，表皮组织上的 S. Poona 初始种群（4.26-5.04 log CFU/样品）减少到通过富集培养物检测。当 S. Poona 在哈密瓜浸泡处理后引入时，当哈密瓜用 LV 处理时，在茎疤处观察到更大的病原体种群减少。在处理组 2 中，将用 5% LV/2.5% SDS 浸泡处理的 S. Poona 的反应与模拟商业倾卸罐处理（200 ppm 氯）以及采用氯罐和 LV/SDS 浸泡处理的两阶段处理进行比较。处理后的 S. Poona 水平（log CFU/样品或富集培养物中阳性的#/分析的#）分别为 5.25、3.07、7/10、5/10（茎疤）和 3.90、25/40、28/40、20/40（表皮）为未经处理、氯罐、LV/SDS 浸泡和罐加浸泡处理。在处理组 3 中，新鲜收获的哈密瓜首先在田间使用无针茎疤注射（200 μl，7.5% LV/1.0% SDS，60 psi）和哈密瓜喷雾（30 ml，7.5% LV/0.5% SDS）进行处理。然后使用液体或基于土壤的培养基对哈密瓜的茎疤和表皮组织进行点接种，然后进行模拟倾卸罐处理，其中包含 200 ppm 氯或 5% LV/2% SDS。田间处理后的哈密瓜表皮组织接种 S. Poona 后，模拟氯和 LV/SDS 罐处理后，分别减少了 4.7 和 5.31（液体）和 3.27 和 3.36（土壤）log CFU/样品。在茎疤组织中，当哈密瓜用 LV/SDS 处理时，与倾卸罐中的氯相比，S. Poona 种群减少了 1.0 个对数级（P<0.05）。基于这项研究，需要应用多种障碍，因为当哈密瓜先进行氯倾卸罐处理，然后再进行 LV/SDS 浸泡处理时，S. Poona 种群的减少更多。
