Behavior and changes in cell morphology of Escherichia coli O157:H7 in liquid medium and skim milk in the presence of caffeine

Figures & data

Figure 1. Growth of E. coli O157:H7 (a) strain E0019 (b) strain 43895, and (c) strain H1730 in TSBYE at 37°C for 48 h with different concentrations of caffeine.

Figura 1. Crecimiento de E. coli O157:H7 (a) cepa E0019, (b) cepa 43895, y (c) cepa H1730 en TSBYE a 37°C durante 48 horas con distintas concentraciones de cafeína.

Figure 2. Population of E. coli O157:H7 in TSBYE in the presence of caffeine after incubation at 37°C for 48 h. Means (± standard error) with different letters within the groups are significantly different (P < 0.05).

Figura 2. Población de E. coli O157:H7 en TSBYE en presencia de cafeína tras ser incubada a 37°C durante 48 horas. Medias (± error estándar) con distintas letras dentro del grupo son significativamente diferentes (P < 0.05).

Table 1. Population of E. coli O157:H7 (log CFU ml⁻¹) in milk sample treated with caffeine (Cf) for 48 h at 37°C.

Tabla 1. Población de E. coli O157:H7 (log CFU ml^–1) en muestra de leche tratada con cafeína (Cf) durante 48 horas a 37°C.

	Time (h)
Cf (g/L)	0	6	12	24	48
0	2.54^a ± 0.23	6.50^a ± 0.26	8.35^a ± 0.04	8.57^a ± 0.12	8.84^a ± 0.03
4.0	2.51^a ± 0.18	3.65^b ± 0.20	5.87^b ± 0.17	7.60^b ± 0.24	7.78^b ± 0.09
5.0	2.48^a ± 0.20	3.19^b ± 0.07	4.93^c ± 0.05	6.89^c ± 0.15	7.31^b ± 0.28

Note: Mean values in the same column with different letters are significantly different (P < 0.05).

Figure 3. Contour plots demonstrating changes in the morphology of E. coli O157:H7 (strain 43895) treated with caffeine (a) Cf 0 g/L (b) Cf 3.0 g/L (c) Cf 4.0 g/L, and (d) Cf 5.0 g/L.

Figura 3. Gráficas de contorno mostrando cambios en la morfología de E. coli O157:H7 (cepa 43895) tratada con cafeína (a) Cf 0 g/L, (b) Cf 3.0 g/L, (c) Cf 4.0 g/L, y (d) Cf 5.0 g/L.