Pulsed
light could inactivate Salmonella in liquid eggs
By Jane Byrne, 16-Jan-2009
Source of Article: http://www.foodproductiondaily.com/Quality-Safety/Pulsed-light-could-inactivate-Salmonella-in-liquid-eggs A new
study claims pulsed electric field (PEF) combined with heat treatment may
have an advantage over high-temperature treatment for pasteurisation of
liquid whole egg (LWE).
According to the
authors of the study, which was published in the International Journal of
Food Science and Technology, PEF exposes a fluid or semi-fluid product to
short pulses of high-energy electricity, which can inactivate microorganisms.
PEF processing, the
research team claims, causes minimal or no detrimental effect on food quality
attributes. The scientists said
that occurrences of egg-related outbreaks of Salmonellosis
have heightened the concern for the safety of egg-related products, with the
food industry now exploring various methods of killing harmful pathogens
while trying to maintain quality. Quality impairment According to the
authors, heat sterilisation techniques, while common, can also lower quality.
At present, LWE is
pasteurised in the The scientists said
that, therefore, it would be desirable to have a new and improved processing
technique for improving the safety of liquid egg products. Objective In this study, effects
of PEF, temperature, pH and PEF with mild heat on the inactivation of Salmonella
typhimurium cells in liquid whole egg (LWE)
were investigated, said the authors. They explained that
cells of Salmonella typhimurium DT104 were
chosen because they were considered a dangerous phage type that was resistant
to ampicillin, chloramphenicol,
streptomycin, sulfonamides and tetracycline. Results The authors found that
the effectiveness of PEF pasteurisation to inactivate pathogenic S. typhimurium DT104 in liquid egg relied on the pH of
the liquid egg and the treatment temperature: “The PEF inactivation
of S. typhimurium cells at 15 or 25 °C was pH
dependent. Heat treatment at 55 °C for 3.5 minutes or PEF treatment at 20 °C
resulted in c. 1-log reduction of S. typhimurium
cells.” The researchers said
that increasing treatment temperature at neutral pH enhanced the
effectiveness of PEF treatment, and the blend of PEF treatment with mild heat
reduced liquid egg pasteurisation temperature while achieving similar
reduction of the pathogen. “The combination of
PEF +
55 °C achieved 3-log reduction of S. typhimurium
cells and was comparable to the inactivation by the heat treatment at 60 °C
for 3.5 min,” said the authors. The researchers
concluded that their study demonstrated a possible approach to increase the
efficiency of PEF in microbial reduction in liquid eggs, and that other
studies have indicated that the addition of bactericides increased the
efficiency of PEF processing. They said, therefore,
with further development or modification, PEF processing could have offer
food manufacturers greater benefits over high-temperature pasteurisation in
ensuring the microbial safety of liquid eggs
with a minimal loss of quality attributes. Source: International
Journal of Food Science and Technology, Volume 44, Issue 2 |
Copyright (C) All rights reserved under FoodHACCP.com
If you have any comments, please send your
email to info@foodhaccp.com
