Antimicrobial activity of chitosan films containing nisin, peptide P34, and natamycin

Figures & data

Table 1. Antimicrobial activity of chitosan films incorporating nisin or peptide P34.
Tabla 1. Actividad antimicrobiana de películas de quitosano incorporando nisina o péptido P34.

	Diameter (mm) of the inhibition zone
Bacteria	Chitosan 10 g l^−1	Chitosan 10 + nisin	Chitosan 10 + P34	Chitosan 15 g l^−1	Chitosan 15 + nisin	Chitosan 15 + P34
L. monocytogenes	11.5 ± 0.5^a,b	12.8 ± 1.6^a,b	13.0 ± 1.0^b	10.8 ± 0.7^a	11.5 ± 2.6^a,b	13.5 ± 1.5^b
B. cereus	10.8 ± 0.7^a	13.3 ± 1.2^b	10.3 ± 0.5^a	10.5 ± 1.7^a,b	10.8 ± 1.4^a,b	10.0 ± 0.5^a
E. coli	9.6 ± 0.2^a	12.5 ± 1.7^c	14.0 ± 1.8^c	7.8 ± 0.2^b	12.5 ± 2.1^c	12.8 ± 1.7^c
S. enteritidis	9.1 ± 0.6^a	9.5 ± 0.5^a,b	11.3 ± 1.5^b	9.5 ± 0.6^a,b	10.8 ± 1.2^a,b	9.0 ± 0.7^a
S. aureus	10.0 ± 0^a	12.1 ± 1.5^b,c	13.5 ± 1.3^b,c	10.0 ± 1.0^a,b	10.0 ± 1.5^a,b	11.5 ± 0.5^b
L. acidophilus	11.0 ± 0^a	10.3 ± 2.5^a,b	14.1 ± 0.7^c	11.3 ± 0.2^a	10.0 ± 0^b	14.6 ± 1.2^c
C. perfringens	10.0 ± 0.5^a	11.5 ± 1.8^a	14.8 ± 0.2^b	10.1 ± 0.2^a	10.6 ± 2.5^a	20.3 ± 0.5^c
Notes: ^aDifferent letters indicate significant differences within the same row (P < 0.05). Values are the means ± s.e.m. of triplicate experiments. Notas: ^aLetras diferentes indican diferencias significativas en la misma línea (P < 0,05). Los valores representan la media ± s.e.m. de tres experimentos.

Table 2. Antimicrobial activity of chitosan films incorporating natamycin.
Tabla 2. Actividad antimicrobiana de películas de quitosano incorporando natamicina.

	Diameter (mm) of the inhibition zone
Fungi	Chitosan 10 g l^−1	Chitosan 10 + natamycin	Chitosan 15 g l^−1	Chitosan 15 + natamycin
A. phoenicis	11.3 ± 0.2^a	11.8 ± 2.4^a	11.3 ± 1.2^a	11.0 ± 0^a
P. stoloniferum	9.0 ± 0.8^a	10.0 ± 1.7^a	9.6 ± 0.5^a	10.3 ± 1.5^a
Notes: ^aValues were not significantly different from each other at P < 0.05. Values are the means ± s.e.m. of triplicate experiments. Notas: ^aLos valores no presentaron diferencias significativas para P < 0,05. Los valores representan la media ± s.e.m. de tres experimentos.

Table 3. Antimicrobial activity of chitosan films incorporating nisin, peptide P34, or natamycin in situon minimally processed pear cubes.
Tabla 3. Actividad antimicrobiana de películas de quitosano incorporando nisina, péptido P34 o natamicina in situen cubos de pera mínimamente procesada.

	Total counts (log10CFU g^−1)		Yeast and molds (log10CFU g^−1)
Treatment	Day 1	Day 7	Day 1	Day 7
Control	nd	2.49 ± 0.05^a	3.66 ± 0.06^a	4.96 ± 0.05^a
Chitosan	nd	2.05 ± 0.16^b	1.67 ± 0.06^b	4.02 ± 0.13^b
Chitosan +nisin	nd	1.85 ± 0.02^c	1.69 ± 0.07^b	4.11 ± 0.04^b
Chitosan +P34	nd	1.79 ± 0.08^c	1.60 ± 0.10^b	3.50 ± 0.08^c
Chitosan +natamycin	nd	1.88 ± 0.08^b,c	1.68 ± 0.06^b	3.69 ± 0.12^c
Notes: ^aDifferent letters indicate significant differences within the same column (P < 0.05). nd, not detected. Values are the means ± s.e.m. of triplicate experiments. Notas: ^aLetras diferentes indican diferencias significativas en la misma línea (P < 0,05). Los valores representan la media ± s.e.m. de tres experimentos.

Figure 1. FTIR spectra of chitosan films incorporating nisin, peptide P34, or natamycin.

Figure 1. Espectros infrarrojos de Transformada de Fourier de películas de quitosano incorporando nisina, péptido P34 o natamicina.

Figure 2. SEM of the surface of chitosan films. Films were prepared with 10 g l⁻¹chitosan (A), containing nisin (B), peptide P34 (C), or natamycin (D).

Figure 2. Microscopía electrónica de barrido de la superficie de películas de quitosano. Las películas se prepararon con 10 g l⁻¹de quitosano (A), formulado con nisina (B), péptido P34 (C) o natamicina (D).