Agriculture Reference
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displayed reductions in aerobic mesophiles compared to those in perforated fi lm
(8.7 and 8.8 log CFU/g). Superatmospheric O
2
and passive MAP also managed to
maintain at low amounts total
Enterobacteriaceae
numbers (Allende et al.
2004a
).
The effect of atmosphere modifi cation (12 % O
2
+ 7 % CO
2
on day 3 and 6 %
O
2
+ 14 % CO
2
on day 7) on the antioxidant constituents of fresh cut spinach stored
at 10 °C for 7 days was evaluated by Gil et al. (
1999
). The effect of both air and
MAP on ascorbic acid content was identical to a decrease to one-half of the initial
value (630 mg/kg) after 3 days of storage and a higher reduction at the end of the
storage period (120 and 100 mg/kg for air and MAP). Within the same period an
accumulation of DHAA was observed on both storage conditions (270 and 650 mg/
kg for air and MAP, respectively).
The effect of irradiation on the elimination of pathogens (
Salmonella
spp. and
Listeria
spp.) combined with MAP (100 % O
2
and an 1:1 O
2
:N
2
atmosphere) inocu-
lated on baby spinach leaves was investigated by Gomez et al. (
2011
). A 5 log
reduction on both studied pathogens can be reached by the application of 0.7 kGy
irradiation and subsequent storage under superatmospheric MAP. The enhanced O
2
in the packages led to a higher irradiation sensitivity (7 to 25 % reduction in D
10
values) that can be attributed to the produced ozone.
Kaur et al. (
2011
) investigated the effect of MAP storage (LDPE and PP fi lms
were used) on spinach leaves of variable in-pack weight (200, 400 and 600 g of
leaves per pack) stored at 15 °C for 4 days. Carotene and ascorbic acid were better
preserved in LDPE packages (22 to 24 and 16 to 23 mg/100 g for carotene in LDPE
packages and PP packages, respectively) compared to PP ones. Phenolic com-
pounds were higher in LDPE packages; 190 to 250 and 30 to 80 mg/100 g FW in
LDPE packages and PP packages, respectively.
According to Lee and Baek (
2008
), spinach inoculated with
E. coli O157
:
H7
was
packed under four different environments (air, vacuum, 100 % N
2
gas, and 100 %
CO
2
gas packaging) following treatment with water, 100 ppm chlorine dioxide, or
100 ppm sodium hypochlorite for 5 min and stored at 7 ± 2 °C. The lowest levels of
E. coli O157
:
H7
were detected in samples ClO
2
treated and stored under vacuum;
1.8, 2.3, 2.6 log CFU/g and 3.9, 3.1, and 4.0 log CFU/g for samples packaged in
vacuum, N
2
gas, and CO
2
gas following treatment with ClO
2
and NaOCl, respec-
tively after 7 days of storage.
Fresh-cut spinach was treated with citric acid and ascorbic acid solutions (varia-
tions from 0 % to 1 %) and packaged in OPP or LDPE bags (passive MAP) and
stored at 4 °C. Mesophiles were affected and their number decreased as citric acid
concentration rose. Even though the citric and ascorbic acid treatment reduced the
pH and the initial microbial load, these effects were neutralized over storage
(Piagentini et al.
2003
).
Rodriguez-Hidalgo et al. (
2010
) examined the effect of fertilization (8, 12 or
16 mmol N L
−1
) combined with MAP storage (passive with a BOPP fi lm used, a
N
2
O enriched atmosphere and a superatmospheric atmosphere with 100 % O
2
) on
quality of fresh baby spinach leaves stored at 5 °C for 10 days. The use of fertilizers
(12 and 16 mmol concentrations) and N
2
O MAP led to the lowest microbial growth
(6.7 and 6.4 log CFU/g for mesophiles for 12 and 16 mmol concentrations, respec-
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