Effectiveness of High Intensity Light Pulses (HILP) treatments for the control of Escherichia coli and Listeria innocua in apple juice, orange juice and milk.
High Intensity Light Pulses (HILP) represent an emerging processing technology which uses short (100-400 μs) light pulses (200-1100 nm) for product decontamination. In this study, model and real foods of differing transparencies (maximum recovery diluent (MRD), apple and orange juices and milk) were exposed to HILP in a batch system for 0, 2, 4 or 8 s at a frequency of 3 Hz. After treatment, inactivation of Escherichia coli or Listeria innocua was evaluated in pre-inoculated samples. Sensory and other quality attributes (colour, pH, Brix, titratable acidity, non-enzymatic browning, total phenols and antioxidant capacity (TEAC)) were assessed in apple juice. Microbial kill decreased with decreasing transparency of the medium. In apple juice (the most transparent beverage) E. coli decreased by 2.65 and 4.5 after exposure times of 2 or 4 s, respectively. No cell recovery was observed after 48 h storage at 4°C. No significant differences were observed in quality parameters, excepting TEAC and flavour score, where 8 s exposure caused a significant decrease (p<0.05). Based on these results, HILP with short exposure times could represent a potential alternative to thermal processing to eliminate undesirable microorganisms, while maintaining product quality, in transparent fruit juices.
Institute of Food and Health, School of Agriculture, Food Science and Veterinary Medicine, UCD Dublin, Belfield, Dublin 4, Ireland.
I
I
Palgan
I M
IM
Caminiti
A
A
Muñoz
F
F
Noci
P
P
Whyte
D J
DJ
Morgan
D A
DA
Cronin
J G
JG
Lyng
D000818:Animals; D001628:Beverages / Q000382:microbiology*; D032084:Citrus sinensis / Q000382:microbiology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D017077:Culture Media, Conditioned; D004926:Escherichia coli / Q000254:growth & development* / Q000528:radiation effects; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D008027:Light; D008087:Listeria / Q000254:growth & development* / Q000528:radiation effects; D027845:Malus / Q000382:microbiology; D008892:Milk / Q000382:microbiology
D017077:Culture Media, Conditioned