Bacteriology and Retail Case Life of Pork After Storage in Carbon Dioxide

Abstract

The effects of prolonged, anoxic storage, under CO2 at −1.5°C, upon the bacteriology and case life of pork on its subsequent transfer to the aerobic conditions of simulated retail display at 8°C was examined. Brochothrix thermosphacta, lactic acid bacteria, enterics, and pseudomonads were enumerated. Panel scores for odor and appearance acceptability were used to quantify retail case life. Lactic acid bacteria were the only bacteria found during loin storage in CO2 for up to 24 weeks. Those organisms reached maximum number of 107 CFU/cm2 within 9 weeks. The number of lactic acid bacteria initially found on the freshly cut surfaces of loin chops increased linearly during the first 9 weeks of loin storage in CO2. Thereafter, they continued to grow on the chops and dominated the spoilage flora during retail display. The pseudomonads grew rapidly and emerged as the next most numerous organism, while B. thermosphacta and enterics showed only limited aerobic growth. The acceptability of pork chop appearance and odor was adversely affected by loin storage time. Each 6-week interval of loin storage produced a 1 d reduction in case life. Should controlled atmospheres be a practicable means of meat distribution to the retail marketplace, efforts will be necessary to assure a maximum case life after their removal from preservative packagings.