Egg salad, which has a higher pH than coleslaw, exhibited Listeria
growth. Other workers (Hwang & Marmer, 2007) have previously
published similar findings. Even raising the concentration
of ferulic acid to 3000 ppm was not sufficient to inhibit
L. monocytogenes growth; in 5 days, growth had increased by
1.8 log CFU/g. A reason for this could be that the antibacterial effect
of ferulic acid decreases, as pH increases