Evaluation of Hydrostatic High Pressure and Cold Storage Parameters for the Reduction of Campylobacter jejuni in Chicken Livers

Abstract

ABSTRACT In recent years, reoccurring Campylobacter-mediated outbreaks of human disease have been linked to undercooked chicken livers. A need exists for interventions to significantly reduce Campylobacter in this widely consumed poultry product. In this study, high pressure processing (HPP) techniques were applied to laboratory-contaminated chicken livers (∼4 × 108 cells per liver) to determine the Campylobacter jejuni–reducing potential of this technology. HPP was able to significantly reduce C. jejuni numbers in chicken livers with the application of 350 MPa for 5 min, resulting in an average reduction of 3.4 log. Unfortunately, when chicken livers were processed in this manner, the surface tissue of the livers turned brown and a fine white foam was produced. A more modest pressure of 250 MPa applied for 10 min resulted in an average reduction in cell numbers of 1.3 log but without an obvious color change in the livers. On average, cold storage conditions (4 and −20°C) were able to produce a 0.2- to 1.3-log reduction, depending on the temperature and storage time. This effect combined with an HPP reduction in an additive fashion. Pulsed HPP techniques failed to produce C. jejuni reductions that exceeded the average reductions compared with constant pressure application using similar time intervals. Hence, HPP is a potential means of reducing C. jejuni numbers in chicken livers, but given its effects on the appearance of the food product at higher pressure levels, it will most likely need to be combined with other intervention techniques. HIGHLIGHTS