Inhibition of germination and outgrowth of Clostridium perfringens spores by buffered calcium, potassium and sodium citrates in cured and non-cured injected pork during cooling

Inhibition of Clostridium perfringens spore germination and outgrowth by buffered calcium, potassium, and sodium citrates (Ca-Cit, K-Cit, and Na-Cit, respectively) during exponential cooling of non-cured and cured pork was evaluated. Antimicrobials were added to a base formulation of a pork product at a final concentration of 0.5, 1.0 or 1.5% w/w along with a control (without citrates). A three strain cocktail of C. perfringens spores was added to achieve a final spore population of 2.5–3.0 log CFU/g. Heat treatment and exponential cooling of inoculated, non-cured and cured control pork from 54.4 °C to 7.2 °C in 6.5, 9, 12, 15, 18, and 21 h resulted in C. perfringens spore germination and outgrowth of 0.52, 1.53, 4.45, 4.81, 5.83, 6.98 log CFU/g and 0.52, 1.55, 3.45, 4.59, 5.65 and 6.04 log CFU/g, respectively. Incorporation of K- or Na-citrates (>1.0%) inhibited germination and outgrowth of C. perfringens spores (<1.0 log CFU/g) compared to the control product. Ca-Cit was more effective in inhibiting C. perfringens spore germination and outgrowth at 0.5% compared to sodium and potassium citrates. Incorporation of Ca, K or Na citrates into pork product formulations can inhibit C. perfringens spores during extended cooling or during cooling process deviations.