Biomedical Engineering Reference
In-Depth Information
by Ukuku et al. (
2004
). These authors reported that the immersion of fresh-cut
cantaloupe melon in H
2
O
2
solution (5 %) caused a 4.6 log CFU/cm
2
reduction of
Salmonella
spp. Similarly, inoculated apples and cantaloupes showed that the same
concentration of H
2
O
2
solutions can achieve 3 log CFU/g reduction at 20 °C (Sapers
et al.
2001
). Combinations of 5 % of H
2
O
2
with acidic surfactants at 50 °C produced
a 3-4 log reduction of nonpathogenic
E. coli
inoculated onto the surfaces of un-
waxed Golden Delicious apples (Sapers et al.
1999
).
4.2.7
Electrolysed Water
Electrolyzed water (EW) has a strong bactericidal effect against pathogens and
spoilage microorganisms. This is more effective than chlorine due to its pH, high
oxidation reduction potential (ORP) and the presence of residual chlorine (Bari
et al.
2003
; Kiura et al.
2002
). This is produced by the electrolysis of ordinary tap
water with sodium chloride in an electrolysis chamber to form acidic and alkaline
EW (Fig.
4.1
). Some studies showed that acidic EW solutions inhibit the growth of
food pathogens in some fruits and vegetables such as strawberries (Koseki et al.
2004a
,
b
), fresh-cut cabbage (Achiwa et al.
2003
), and tomatoes (Bari et al.
2003
).
Acidic EW showed inhibitory effect against
E coli
O157:H7 by reducing their
counts to 4.45 log CFU/g when green onions were treated for 1 min (Park et al.
2008
). They compared their results with distillated water treatment. Koseki et al.
2004a
,
b
evaluated the effect of washing with alkaline EW followed by acidic EW
in cut lettuce against
E. coli
O157:H7 and
Salmonella
spp and they observed a
reduction of microbial populations by approximate 1.8 log CFU/g (Table
4.1
).
4.2.8
Trisodium Phosphate
Trisodium phosphate (Na
3
PO
4
) is highly soluble in water and it produces an alkaline
solution. The antimicrobial activity of TSP probably is due to its high pH (pH 12)
which disrupts the cytoplasmic membrane (Sampathkumar et al.
2003
). Zhuang and
Beuchat (
1996
) studied the effectiveness of TSP treatment on the inactivation of
Salmonella
Montevideo on tomatoes. They found that dipping tomatoes in a solu-
tion at 80 and 120 mg/mL for 15 s reduced the microbial population by 2.46 and
3.46 log CFU/ml, respectively. On the other hand, Kamber et al. (
2010
) evaluated
the effect of 1 % of TSP on
Salmonella enteritidis
and the results showed more than
5 log CFU/mL reduction in the cases of both species after 15 min. It is well known
that the washing step in preparing fresh-cut fruits and vegetables is vital for main-
taining the quality of the end product. However, peeling and cutting can also dam-
age the tissues of fresh fruits and vegetables. This could cause susceptible to
microbial growth, and leakage of nutrients.
