Abstract:
This study was conducted to investigate the bactericidal effect of nisin (Nisin)
only, atmospheric pressure plasma (APP) only, and a combination of APP and nisin
(APP+Nisin) on beef jerky and sliced ham inoculated with Escherichia coli O157:H7, gram-
negative bacteria. The bactericidal effect against E. coli O157:H7 and Listeria
monocytogenes was confirmed using a nisin solution at a concentration of 0–100 ppm, and
APP+Nisin was tested on beef jerky and sliced ham using 100 ppm nisin. Beef jerky and
sliced ham were treated with APP for 5 min and 9 min, respectively. In the bacterial solution,
100 ppm nisin out of 0–100 ppm nisin exhibited the highest bactericidal activity against L.
monocytogenes (gram-positive bacteria; p<0.05); however, it did not exhibit bactericidal
effects against E. coli O157:H7 (gram-negative bacteria). The APP+Nisin exhibited a 100%
reduction rate in both E. coli O157:H7 and L. monocytogenes compared to the control group,
and was more effective than the Nisin. The APP+Nisin decreased the number of colonies
formed by 0.80 and 1.96 Log CFU/g for beef jerky and sliced ham, respectively, compared to
the control, and exhibited a higher bactericidal effect compared to the Nisin (p<0.05). These
results demonstrate the synergistic bactericidal effect of APP and nisin, providing a possible
method to improve the limitations of nisin against gram-negative bacteria. In addition, this
technology has the potential to be applied to various meats and meat products to control
surface microorganisms.
