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Effect of Hyperbaric Carbon Dioxide Pressure on the Microbial Flora of Pork Stored at 4 or 14°C
Author(s) -
BLICKSTAD E.,
ENFORS S.O.,
MOLIN G.
Publication year - 1981
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1981.tb04252.x
Subject(s) - flora (microbiology) , food science , micrococcus , carbon dioxide , biology , chemistry , microbiology and biotechnology , bacteria , ecology , genetics
Changes in the microbial flora of pork stored at 4 or 14°C were studied in 5 atm CO 2 , 1 atm CO 2 or 1 atm air. The time needed for the total aerobic count at 4°C to reach 5 × 10 6 organisms/cm 2 was about three times longer in 5 atm CO 2 than in 1 atm CO 2 , and about 15 times longer in 5 atm CO 2 than in air. At 14°C there was no difference in growth rate between 5 atm CO 2 and 1 atm CO 2 . No off‐odour was detected after storage in 5 atm CO 2 for 14 d, but the pork in 1 atm CO 2 (6 d) was organoleptically unacceptable. The predominant organisms on the pork from the processing line were: Flavobacterium spp., Acinetobacter calcoaceticus, Pseudomonas spp., Micrococcus spp. and Moraxella spp. After aerobic storage at 4°C (8 d) or 14°C (3 d) more than 90% of the flora consisted of Pseudomonas spp. At 4°C all Pseudomonas spp. were of the non‐fluorescent type, whilst at 14°C 32% were Ps. putida and Ps. fluorescens. After storage in 1 atm CO 2 Lactobacillus spp. represented 66% of the flora at 14°C (6 d) and 100% at 4°C (40 d), with L. xylosus dominating. After storage in 5 atm CO 2 Lactobacillus spp. constituted the total flora at both temperatures with L. lactis (14°C) and L. xylosus (4°C) dominating. It was concluded that high partial pressures of CO 2 have a considerable shelf‐life prolonging effect by (i) selecting the microflora towards Lactobacillus spp. and (ii) reducing the growth rate of these Lactobacillus spp. The controlling and growth inhibitory effect of CO 2 was promoted by reduced temperatures.