Inactivation of human pathogens and spoilage bacteria on the surface and internalized within fresh produce by using a combination of ultraviolet light and hydrogen peroxide.
OBJECTIVE
To evaluate the efficacy of ultraviolet (UV) light (254 nm) combined with hydrogen peroxide (H(2)O(2)) to inactivate bacteria on and within fresh produce.


RESULTS
The produce was steep inoculated in bacterial cell suspension followed by vacuum infiltration. The inoculated samples were sprayed with H(2)O(2) under constant UV illumination. The log count reduction (LCR) of Salmonella on and within lettuce was dependent on the H(2)O(2) concentration, temperature and treatment time with UV intensity being less significant. By using the optimized parameters (1.5% H(2)O(2) at 50 degrees C, UV dose of 37.8 mJ cm(-2)), the surface Salmonella were reduced by 4.12 +/- 0.45 and internal counts by 2.84 +/- 0.34 log CFU, which was significantly higher compared with H(2)O(2) or UV alone. Higher LCR of Escherichia coli O157:H7, Pectobacterium carotovora, Pseudomonas fluorescens and Salmonella were achieved on leafy vegetables compared with produce, such as cauliflower. In all cases, the surface LCR were significantly higher compared with the samples treated with 200 ppm hypochlorite. UV-H(2)O(2)-treated lettuce did not develop brown discolouration during storage but growth of residual survivors occurred with samples held at 25 degrees C.


CONCLUSIONS
UV-H(2)O(2) reduce the bacterial populations on and within fresh produce without affecting the shelf-life stability.


CONCLUSIONS
UV-H(2)O(2) represent an alternative to hypochlorite washes to decontaminate fresh produce.
Hadjok
C
C
Department of Food Science, University of Guelph, Guelph, Ontario, Canada.
Mittal
G S
GS
Warriner
K
K
D001419:Bacteria / Q000187:drug effects / Q000528:radiation effects*; D003114:Colony-Forming Units Assay; D019453:Escherichia coli O157 / Q000187:drug effects / Q000528:radiation effects; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D006861:Hydrogen Peroxide; D018545:Lactuca / Q000382:microbiology; D018551:Solanum lycopersicum / Q000382:microbiology; D016973:Pectobacterium carotovorum / Q000187:drug effects / Q000528:radiation effects; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000528:radiation effects; D012475:Salmonella / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays; D014675:Vegetables / Q000382:microbiology
D006861:Hydrogen Peroxide