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. 2020 Apr 29;12(3):268–289. doi: 10.1007/s12393-020-09221-4

Table 2.

The antimicrobial efficacy of LED in solid foods

Tested food product LED used Tested microorganisms Quality and mode of action Major findings References
Sliced camembert cheese UV emitting peak wavelengths 266, 270, 275, and 279 nm; dose, 1, 2, and 3 mJ/cm2, respectively; radiation intensity, about 4 W/cm2 E. coli O157:H7, S. Typhimurium and L. monocytogenes The 3 mJ/cm2 dose resulted in 4 to 5 log reduction in E. coli, S. Typhimurium and L. monocytogenes Kim et al. [56],
Shelled almonds 405 nm MBL LED lights; working distance, 7 cm; treatment time, 0, 1, 2, 4, 6, 8, and 10 min Pathogenic E. coli O157:H7, non-pathogenic E. coli K12, pathogenic S. Enteritidis (PT30, Stanley and Anatum) and non-pathogenic S. Typhimurium strain Chi3985 with 8 or 5 CFU/g inoculum levels

Following log reductions for higher and lower inoculum levels, respectively:

E. coli O157:H7, 2.44 and 1.44 log CFU/g

E. coli K12, 1.85 and 1.63 log CFU/g

S. Enteritidis, 0.7 and 0.55 log CFU/g

S. Typhimurium, 0.54 and 0.97 log CFU/g

Lacombe et al. [66]
Fresh-cut papaya 405 ± 5 nm LED treatment with 0.9–1.7 kJ/cm2 (24–28 h), 10 ± 1 mW/cm2; working distance 4.5 cm in the temperature-controlled incubator (4, 10, or 20 °C) S. Agona, S. Newport, S. Saintpaul and S. Typhimurium No significant cellular lipid oxidation, significant DNA oxidation, no significant color change and antioxidant capacity, 1.5–1.9 times higher total flavonoid content, no significant change in the ascorbic acid, β-carotene and lycopene content 0.3–1.3 log CFU/cm2 reduction in Salmonella cells at 1.3–1.7 kJ/cm2 dose Kim et al. [58]
Fresh-cut mango 405 ± 5 nm LED; irradiance, 20 ± 2 mW/cm2; at 4, 10, or 20 °C illumination temperature; treatment times, 24–48 h; total dose, 1.7–3.5 kJ/cm2 in a temperature-controlled incubator Three strains of E. coli O157:H7, 3 serotypes of L. monocytogenes and 5 serotypes of Salmonella No significant changes in the color, antioxidant capacity, total flavonoid content, ascorbic acid content, and β-carotene of the LED treated mangoes 2.6–3.5 kJ/cm2 of LED light resulted in 1–1.6 log CFU/cm2 at 4 and 10 °C in all the bacterial species and; 1.2 log CFU/cm2 reduction in Salmonella at 20 °C with 1.7 kJ/cm2 dose Kim et al. [59]
Fresh-cut pineapples 460 nm LED with irradiance of 92.0, 147.7 or 254.7 mW/cm2, corresponding to the working distances (4.5, 3.5 and 2.5 cm, respectively); illumination times (24, 13.91 and 8.66 h) to produce the same dose of 7950 J/cm2 to the slices. A cocktail of five serovars of Salmonella enterica Gaminara, Montevideo, Newport, Saintpaul, and Typhimurium Discolouration of treated pineapple slices Significant effect of illumination temperature on the antibacterial efficacy; inactivation ranged from 0.61 to 1.72 log CFU/g Ghate et al. [36]
Satsuma mandarin fruits 465 nm blue LEDs with low (8 μmol/m2/s) and high (80 μmol/m2/s) fluency Penicillium italicum Radial growth of sporulation zone was found to be 0.3 and 3 mm/day for high and low fluency, respectively. LED-80 produced suppression of sporulation till day 6 after inoculation Yamaga et al. [132]
Blueberries Green, red, blue, and white LEDs; working distance, 30 cm Bacillus amyloliquefaciens and Lactobacillus brevis for fermentation and Propionibacterium acnes and Staphylococcus epidermis for antimicrobial study Green and white LED increased the total phenolic content and total flavonoid content in fermented blueberry extract White and green LED effective in improved fermentation for 72 h and improved antibacterial activity Jeong et al. [46]
White mushrooms and commercial ready-to-eat (fully cooked) sausages Three UV-C LEDs (280 nm) were combined; working distance-3 cm; varied duty cycle; irradiance, 1 to 5 J/cm2, continuous and pulsed irradiation E. coli O157:H7 (ATCC 35150, ATCC 43889, and ATCC 43890), Salmonella enterica serovar Typhimurium (ATCC 19585, ATCC 43971 and DT 104), and Listeria monocytogenes (ATCC 19111, ATCC 19115, and ATCC 15313) LED treatment reduced formazan formation levels in E. coli and Listeria; pulsed LED produced more ROS and membrane lipid peroxidation compared to continuous irradiation; no significant effect on membrane damage but effect on membrane potential of E. coli and Listeria

Continuous and pulsed irradiation resulted in the following inactivation, respectively:

White mushrooms:

E. coli, 2 and 2 log CFU/g; Salmonella, 1 and 1.5 log CFU/g; Listeria- 1 and 1.8 log CFU/g

RTE sausages:

E. coli, 2 and 3 log CFU/g; Salmonella, 1.5 and 4 log CFU/g; Listeria, 2 and 4 log CFU/g

Kim and Kang [50]
Cooked chicken 405 ± 5 nm LED; working distance, 3 cm; surface intensity on cooked chicken 22.0 ± 1.1 mW/cm2; dose, 1.58-3.80 kJ/cm2; treatment times, 20-48 h; illumination temperature, 4, 10, and 20 °C Salmonella enterica Enteritidis (124, 125, and 130) Salmonella cells incapable of cellular repair at 4 °C 0.8–0.9 log CFU/cm2 reduction on cooked chicken in all Salmonella spp. with 3.8 kJ/cm2 dose at 4 °C; growth delays observed at 10 and 20 °C Kim et al. [57]
Smoked salmon 460 nm LEDs; working distance, 9 cm (intensity of 15 mW/cm2) to 5.4 cm (intensity of 58 mW/cm2); dose maintained at 2400 J/cm2 Four serotypes of Listeria monocytogenes 0.7–1.2 log CFU/cm2 reduction with LED treatment in combination with riboflavin (25, 50, and 100 mM) Josewin et al. [47]
Ready-to-eat fresh Salmon 405 nm LEDs; radiation intensity, 26 ± 2 mW/cm2; working distance- 4.5 cm Listeria monocytogenes inoculated on salmon exudates LED treatments effective in reduction of Listeria during the biofilm formation LED treatment produced 2–2.8 log reduction in planktonic cells on stainless steel or acrylic coupons in salmon exudates during 8 h storage Li et al. [72]
405 nm LED; intensity, 16 ± 2 mW/cm2; treatment time, 8 h; illumination temperature, 4 and 12 °C; working distance −7.9 cm Listeria monocytogenes and Salmonella enterica serotype Enteritidis, Typhimurium and Newport LED treatment produced insignificant color change; it improved the sensitivity of the bacteria to simulated gastric fluid Reduction of 0.4 and 0.3 log CFU/cm2 in L. monocytogenes; reduction of 0.5 and 0.4 log CFU/cm2 in Salmonella at 4 and 12 °C, respectively Li et al. [73]