This study investigated the inactivation effect of intense pulsed light (IPL) on various packaging films. The UV-C transmittance irradiance varied depending on the packaging materials, with the control group having an irradiance of 3.959 W/m2. For the thinnest layer of 30 mm, polypropylene (PP) had an irradiance of 3.258 W/m2, polyethylene (PE) had an irradiance of 3.193 W/ m2, and oriented polypropylene (OPP) had an irradiance of 3.200 W/m2. In contrast, polyethylene terephthalate (PET) exhibited a significantly lower irradiance of only 0.065 W/m2 for its thinnest film thickness of 100 mm. The light transmittance of the packaging materials was similar, with values of 91.3%, 89.7%, and 89.5% for PP, PE, and OPP, respectively. In contrast, PET exhibited a significantly lower light transmittance of 1.8% compared to the other packaging materials. These findings have practical implications for the food packaging industry. According to the packaging film material, the sterilization effects showed that the E. coli sterilization effect of PP was the highest, followed by PE and OPP, which were similarly effective. At the same time, PET exhibited the lowest sterilization effect. For PP film with a thickness of 30 mm, a 6.2 log reduction in the E. coli population was observed after 20 s of IPL treatment. Ultimately, inactivation was achieved after 60 seconds. Both PE and OPP films, which had a thickness of 30 mm, showed a 5.9 log reduction in E. coli after 30 s of IPL treatment, followed by complete inactivation after 60 s. The inactivation rate for PP, PE, and OPP films showed minimal variation regardless of thickness, although it gradually decreased with increasing thickness. For PET, achieving a 1 log reduction in E. coli required 180 s of IPL treatment at 100 mm thickness and 210 s at 120 mm thickness, indicating the influence of film thickness on inactivation rate. Even after 300 s of IPL treatment, the inactivation effect for PET remained around 1.5 log, the lowest among all packaging film materials.

This study evaluated the microbiological quality of fresh-cut bell pepper and ginger, as well as the inactivation effects of intense pulsed light (IPL) on E. coli ATCC 25922 inoculated in the fresh-cut samples by varying the treatment voltages (1,200-2,400 V) and time (1–7 min). The contamination levels of mesophilic bacteria, psychrophilic bacteria, yeast and mold for bell pepper and ginger were 6.64±0.81 and 6.35±1.96 log CFU/g, 6.75±1.13 and 5.63±1.89 log CFU/g, and 4.68±0.43 and 4.57±1.25 log CFU/g respectively. Through the IPL treatment at 2,400 V for 7 min, 2.04 and 2.11 log of E. coli ATCC 25922 inoculated in bell pepper and ginger were reduced, respectively, with a negligible temperature rise (< 2.2oC). Although the reduction rate varied, the bactericidal effect of E. coli ATCC 25922 showed an increase as treatment time and voltage increased. Under the same treatment conditions, temperature increased by 1.71oC and 2.13oC for bell pepper and ginger, respectively. These results demonstrate that IPL is a suitable device for inactivating E. coli ATCC 25922 on fresh-cut bell pepper and ginger.

Because of many benefits from raw seed sprouts, consumers have consumed them largely. However, despite of many benefits, raw sprouts has been implicated in food-borne diseases. The source of food-borne disease related to raw seed sprouts is thought to originate from seeds contaminated by pathogenic bacteria. So, Intense Pulsed Light (IPL), a non-thermal processing method, is an effective device for seeds to maintain microbial safety without loss of seed viability. The objective of this research was to determine the effects on microbial inactivation and quality in radish and wheat seed by IPL treatment and to figure out the correlation between inactivation of seeds and surface roughness value (Ra). At 5th day of germination, the average germination rate and shoot length of radish sprouts by IPL at total fluences of 121 J/cm2 were 95% and 5.8 cm. It was not significant compared to the control group. And log reductions of radish and wheat seeds by IPL showed 1.0 and 1.2, respectively. The results showed radish seeds have higher tolerance to IPL treatment than wheat seed. Also, radish seed had the rougher surface (Ra=2.85 μm) than wheat seed (Ra=0.55 μm). Therefore, IPL can decontaminate microbial population on seeds, but the effectiveness of IPL is dependent on the surface morphology of seeds.