Agriculture Reference
In-Depth Information
5 °C was determined. PMP pods were the best and OPP the worst in terms of
external appearance while precooling proved helpful. The application of CA with
5-10 kPa O
2
with 5 kPa CO
2
proved to be the most effective, since the changes in
organic acid, free amino acid, sugar contents, and sensory attributes were negligible
(Pariasca et al.
2000
).
1.7.8.3
Fungi
Truffl es
Gamma irradiation (doses of 1.5 kGy and 2.5 kGy of either one) and subsequent
PMAP (a 25
m fi lm was used) storage was used for
Tuber aestivum
truffl es
preservation. Treatment with 2.5 kGy irradiation led to doubling the shelf life of
samples (42 days) by restraining microbial populations (5.8, 5.1, >6, 2.8, and >2.4
log CFU/g reduction on mesophile,
Pseudomonas
,
Enterobacteriaceae
, LAB and
yeasts counts, respectively compared to control) and preserving texture and aroma
characteristics (Rivera et al.
2011a
).
Treatments with electron beam and gamma irradiation (doses of 1.5 kGy and
2.5 kGy of either one) were tested on
Tuber melanosporum
truffl es stored under
MAP for 35 days at 4 °C. Mesophile growth was reduced by both treatments (4.3,
5.6, 6.4 and 6.6 log CFU/g for 1.5, 2.5 respectively).
Candida sake
and
Candida
membranifaciens
var.
santamariae
survived and were the dominant microbial popu-
lations. The use of high irradiation dosages did not favor texture characteristics
thereby limiting the shelf life to 28 days (Rivera et al.
2011b
).
A shelf life of 28 and 21 days was achieved for
T. melanosporum
and
T. aestivum
truffl es respectively stored at 4 °C under PMAP (a Mi-P fi lm was used) microbial
load was reduced (2 and 1.2 log CFU/g reduction for mesophiles, 3.7 and 1 log
CFU/g reduction for
Enterobacteriaceae
and 2.8 and 0.8 log CFU/g reduction for
Pseudomonas on
T. melanosporum
and
T. aestivum
samples, respectively stored
under MAP when compared with air stored samples) and texture and sensory charac-
teristics (aroma, color) where better preserved on MAP samples (Rivera et al.
2010
).
A 4 log reduction for pseudomonads, more than 2 log reductions for
Enterobacteriacae
, moulds and LAB and 1.5 log reductions for yeasts on
Tuber
aestivum
and
Tuber melanosporum
truffl es surface was achieved by dipping in 70 %
ethanol combined with 35 Hz ultrasound treatment. The subsequent storage under
MAP (a microperforated LDPE fi lm was used) at 4 °C led to a shelf life of 28 days
for both truffl es species (Rivera et al.
2011c
).
ʼ
Mushrooms
Antmann et al. (
2008
) investigated shiitake mushrooms stored under passive (two
macroperforated PE fi lms used, PE
A
and PE
B
) and active (15 % O
2
and 25 % O
2
in a
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