Synergic antimicrobial activity of lysozyme (250 ppm), nisin (250 ppm), and disodium ethylenediamine tetraacetic acid (EDTA) (20 mM) against Listeria monocytogenes and meat-borne spoilage bacteria in ostrich patties packaged in air and vacuum was studied. The antimicrobial treatment decreased the L. monocytogenes population in ostrich patties below the official limit of the European Union (<2 log CFU/g). The total viable counts for the treated samples (air and vacuum) showed a reduction of 1 log cycle until to 2 d of storage; after this period the cell load increased. Moreover, the reduction of 2 log cycle for the lactic acid bacteria was observed. Enterobacteriaceae and Pseudomonas spp. were not affected by the antimicrobial treatment in both packaging atmospheres. Sensory evaluation did not differ between treated and untreated samples as regard to the color. The ostrich patties packaged in vacuum had a desirable odor during the storage time and were not affected by antimicrobial treatment. The off-odors for the patties packaged in air developed faster in the control while the odor scores for the treated samples remained above the rejection point up to the end of storage.
Practical application: Great interest is developing in food bio-preservation, because of the ever-increasing needs to protect consumers' health and to valorize the naturalness and safety of food products.