Controlled release of hen egg-white lysozyme from polyhydroxybutyrate particles for the prevention of blown pack spoilage in vacuum-packed lamb.

Blown pack spoilage (BPS) caused by psychrophilic Clostridium spp., including Clostridium estertheticum, is a major contributor to spoilage in chilled vacuum-packed red meat. This study evaluated biologically produced and synthetically made polyhydroxybutyrate (PHB) particles as a controlled-release delivery system for hen egg-white lysozyme (HEWL) and assessed their ability to prevent BPS. Biologically produced PHB particles (bioparticles) demonstrated greater initial HEWL binding (mean 691 ± 53 (SE) units enzyme activity per gram PHB) compared to synthetic particles (182 ± 20 units/g PHB; P < .001) and HEWL release was maintained for a significantly longer duration (P < .001). Measurement of particle size and changes in zeta potential by dynamic and electrophoretic light scattering suggested the outer protein layer of the bioparticles was important for HEWL binding. Given their superior HEWL binding and controlled release, HEWL-loaded bioparticles were tested for BPS prevention in a pilot lab-scale meat trial. Lamb meat samples were inoculated with C. estertheticum spores, vacuum-packed, and stored at 2 °C for 7 weeks. BPS occurred in all untreated samples (8/8, 100%) compared to 3 of 8 samples treated with HEWL-loaded bioparticles (37.5%) (P = .026). This reduction corresponded with decreased presence of C. estertheticum DNA on the treated samples. These results demonstrated that HEWL is effective at inhibiting the growth of C. estertheticum on lamb to prevent BPS and PHB bioparticles are an effective controlled-release delivery system for HEWL.