Pseudomonas spp. convert metmyoglobin into deoxymyoglobin.
Meat 'reddening' by bacteria was observed in chilled beef. To identify the reddening bacteria, isolates were inoculated onto beef and the changes in CIE L*a*b* values monitored. As a result, two Pseudomonas spp., including Pseudomonas fragi which is commonly observed in raw meat, were selected and identified as reddening bacteria. The reddening was coincidentally occurred with the appearance of slime, and the increase in thiobarbituric acid-reactive substances (TBARS) was simultaneously suppressed. In myoglobin-containing nutrient broth, it is shown spectroscopically that P. fragi converted metmyoglobin into deoxymyoglobin. It was concluded that the meat reddening was due to the formation of deoxymyoglobin, induced by the very-low-oxygen tension brought about by Pseudomonad's oxygen consumption: This oxygen depletion simultaneously suppressed TBARS increase.
Motoyama
Michiyo
M
Animal Products Research Team, National Institute of Livestock and Grassland Science, Tsukuba-shi, Ibaraki-ken, Japan. mmichiyo@affrc.go.jp
Kobayashi
Miho
M
Sasaki
Keisuke
K
Nomura
Masaru
M
Mitsumoto
Mitsuru
M
D000818:Animals; D001426:Bacterial Proteins; D018441:Biofilms; D002417:Cattle; D015169:Colony Count, Microbial; D005516:Food Microbiology; D008297:Male; D008460:Meat / Q000032:analysis* / Q000382:microbiology; D008786:Metmyoglobin / Q000032:analysis / Q000378:metabolism*; D009211:Myoglobin / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D009928:Organ Specificity; D010100:Oxygen / Q000737:chemistry; D010858:Pigmentation; D011549:Pseudomonas / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D044206:Pseudomonas fragi / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D021521:Ribotyping; D013045:Species Specificity; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D013997:Time Factors
D001426:Bacterial Proteins; D009211:Myoglobin; D012336:RNA, Ribosomal, 16S; D017392:Thiobarbituric Acid Reactive Substances; C055547:deoxymyoglobin; C017595:oxymyoglobin; D008786:Metmyoglobin; D010100:Oxygen