Produce Degradation Pathways and Prevention

Packaging and Produce Degradation 137

5.2.2.5.2.3 Off-Flavor of Microbial Origin
Off-flavor occurring on spoiled shredded carrots is associated with the following
characteristics: MA with excessive CO 2 concentrations (over 30%) and low O 2
content (below 1%) and high counts of acid lactic bacteria (LAB) and yeasts along
with the accumulation of ethanol and acetic and lactic acids. The main microbial
contaminant was identified as Leuconostoc mesenteroides [126]. However, the initial

FIGURE 5.12Hexanoate and ethyl propanoate as a function of atmosphere composition.
(From Guichard, E. et al., Sci. Aliments, 12, 83, 1992. With permission.)

FIGURE 5.13Changes in ethanol production of litchis as a function of storage duration at
1°C under different atmosphere compositions. (From Varoquaux, P. et al., Sci. Aliments, 10,
127, 1990.)

Ethyl propanoate

Hexanoate

air(20)0initial

(10)10

(1^8

(14)30(16)20)10

0

10

20

30

40

50

60

70

80

90

Concentration (mg

.kg

−^1

)

Atmosphere

composition

(O 2 ) CO 2

0

20000

40000

60000

80000

100000

120000

0 1020304050

Storage duration (days)

Ethanol (ua.h

−^1

.kg

−^1

)

air 2-10 5-5

5-15 5-20