본 연구는 저온살균(60oC, 5-20분)과 대기압플라즈마(5- 20분)를 병용한 고춧가루 중의 E. coli 저감화 및 시너지 효과를 조사하였다. 저온살균 단일처리시 대장균의 불활 성화는 최대 2 log10 CFU/g(=99% 감소) 이상 나타내었으며, 대기압플라즈마 5, 10, 15, 및 20분간 단일처리 하였을 때 각각 0.4, 0.8, 0.9 및 1.4 log10 CFU/g 감소되었다. 저온 살균 및 대기압플라즈마 단독 처리만으로는 만족할 만한 미생물 저감화효과를 얻을 수 없었기에 저온살균 처리 후, 대기압플라즈마를 병용처리 하여 대장균의 불활성화는 1- 6 log10 CFU/g 이상 감소되었다. 그러나, 저온살균과 대기 압플라즈마 병용처리에 따른 관능적 품질 (색, 이취, 맛, 조 직감 및 전체적인 기호도)에 대한 유의적인 차이는 관찰 되지 않았다(P>0.05). 따라서 고춧가루의 미생물학적 안전성 확보를 위해 저온살균과 대기압플라즈마 단독처리보다 이 둘의 병용처리가 E. coli의 확실한 저감화 효과를 유도 하고 식품 고유의 품질특성을 유지하는데 효과적이었음을 본 연구를 통해 확인되었다.
This study investigated the inactivation and synergistic efficacy of combined low-temperature heating (LT) and atmospheric plasma (AP) against Escherichia coli in red pepper powder. A cocktail of two strains of E. coli (ATCC 11229, KCCM 11234) was inoculated onto red pepper powder and then treated with LT (60oC for 5-20 min) and AP (atmospheric plasma for 5-20 min). The counts of E. coli in the red pepper powder were significantly (P<0.05) reduced with the increase in treatment time using LT and AP. The reduction of E. coli levels in red pepper powder when treated with LT alone for 5, 10, 15, and 20 min were 0.25, 1.45, 2.54, and 2.85 log10 CFU/g, respectively. Also, the reduced levels of E. coli on red pepper powder when treated with AP alone for 5, 10, 15, and 20 min were 0.19, 0.32, 0.54, and 0.96 log10 CFU/g, respectively. The synergistic effects were not dependent on the treatment time with AP, but were dependent on the LT treatment time. Synergistic reduction values for combined LT and AP treatment against E. coli in red pepper powder were -0.13 to 2.91 log10 CFU/mL, respectively. Especially, the largest synergistic values (2.91-2.82 log10 CFU/mL) of E. coli in red pepper powder were revealed by the combination of a 20- min treatment with LT and a 15-20-min treatment with AP. All sensory parameters (color, off-odor, taste, texture, and overall acceptability) were not significantly (P>0.05) different between non-treated and all combination-treated samples. Therefore, these results suggest that the combination of LT and AP can be potentially utilized in the food industry to effectively inactivate E. coli without incurring quality deterioration in red pepper powder.