2002). Hence, the shelf life of the CON sample is estimated as about
6 days, based on microbiological data.
Total bacterial count of GOG10 treated samples exceeded
6.0 lg cfu g1 on day 9 and the value reached to 7.5 lg cfu g1 on
the 12th day, which resulted in 1log reduction compared with
the CON. GOG5 treated samples reached the value of 7.9 lg cfu g1
on the 12th day which showed slightly worse effect on anti-microbial
growth than GOG10 treated ones. CHI1 treated samples
reached the acceptable limit on day 12, indicating a significantly
delayed microbial spoilage (p < 0.05) than GOG treatment. Mix1
and Mix2 treatments had the lowest total bacterial count during
storage which were lower than acceptable limit even after 12 days
cold storage (reached 4.9 cfu g1 and 5.6 lg cfu g1, respectively).
Thus, a microbiological shelf life extension of 5–6 days was
achieved for Mix treated samples compared with the control.
Results also showed that CHI had better antimicrobial capacity
than GOG, and CHI combined with GOG had possible synergistic
effect on microbial inhibition.
Benkeblia (2004) has researched that sulfur compounds presenting
in garlic and onion could inhibit the gram-positive bacteria
and gram-negative bacteria. Plant extracts possess potential as
natural agents for food preservation with antimicrobial compounds
(Kim, Kim, Kim, Whang, & Suh, 2008). The mode of antimicrobial
capacity of chitosan might be due to its interaction with cell
wall and membranes components, resulting in increased leakage of
cell material from tissue and permeability of the membranes, or
due to its water-binging capacity and inhibition of various enzymes
(Helander, Nurmiaho-Lassila, Ahvenainen, Rhoades, & Roller,
2001). Chitosan also has the ability to absorb nutrients of
microorganisms and thus inhibit their growth (Knorr, 1991).