Owing to the residual toxicity and adverse health effects of chemical
preservatives, there is an increasing demand for using natural preservatives in
food. Although many natural extracts have been evaluated, research on their
antibacterial effects remains insufficient. Therefore, this study aimed to
explore the possibility of developing
Psidium guajava
,
Ecklonia cava
, and
Paeonia japonica
(Makino) Miyabe & Takeda extracts as natural food preservatives. Further,
the effect of mixing these extracts on microbial growth and quality was
evaluated during the refrigeration of sausages. Optimal mixing ratios were
determined based on the minimum inhibitory and bactericidal concentrations of
each mixed extract against the
Listeria monocytogenes
,
Salmonella
spp. and
Escherichia coli
.
D-optimal mixing design optimization tool was further used to obtain an optimum
mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased
with increasing concentration, with similar activities at 0.5% and 1%. The
sausages with synthetic or natural preservatives showed significantly lower
lipid oxidation than those of the control and grapefruit extract-treated
sausages after 4 wk of refrigeration. Total plate counts were observed only in
the control and treatment groups stored for 3 wk, and no significant effect of
ascorbic acid was observed. Compared to the other samples, sausages with added
natural extracts showed the highest overall acceptability scores initially and
after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts
had the same effect on microbiological analysis and lipid rancidity during
sausage storage. Hence, this mixture can serve as a potential natural
preservative in meat products.