Inhibition of natural bacterial flora, Staphylococcus aureus, and enterotoxin A production in cooked ground chicken with oregano oil or tannic acid (TA) alone or combination

Abstract

The effect of oregano oil and tannic acid (TA) on the aerobic plate count, Staphylococcus aureus growth, and staphylococcal enterotoxin A (SEA) production in cooked chicken breast meat held at abusive temperatures were evaluated. Five treatments, namely, control, 200 ppm oregano essential oil, 10 ppm TA, 200 ppm oregano oil + 10 ppm TA, and 5 ppm butylated hydroxyanisole (BHA), were prepared. The antimicrobial effect of TA was weaker than that of the oregano oil or BHA, and TA did not decrease the APC at the end of the storage at 10°C or 25°C. Oregano oil + TA treatment (combination) significantly suppressed the APC at all temperatures (10°C, 25°C, and 43°C) tested. Oregano oil + TA (combination) was the most effective treatment for inhibiting S. aureus growth at 10°C and 25°C. All treatments inhibited SEA production in cooked chicken at 25°C; however, oregano oil + TA (combination) was the most effective in inhibiting SEA production at 10°C and 43°C (7 days and 6 h, respectively). Based on these results, oregano oil has strong antimicrobial activity, which increases when combined with TA. Oregano oil + TA has a good potential for inhibiting the natural bacterial flora, growth of S. aureus, and SEA production in cooked chicken to enhance the microbial quality and safety under temperature abuse conditions.