Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks

There is limited understanding of the relationship between the growth of spoilage microflora and fresh meat color. Therefore, the objective of this study was to investigate the impact of the growth of common spoilage bacteria on the color stability of color-stable (longissimus lumborum; LL) and colo...

Full description

Saved in:
Bibliographic Details
Main Authors: Colton L. Smith, Ifigenia Geornaras, Mahesh N. Nair
Format: Article
Language:English
Published: Iowa State University Digital Press 2024-09-01
Series:Meat and Muscle Biology
Subjects:
Online Access:https://www.iastatedigitalpress.com/mmb/article/id/17796/
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849723708833267712
author Colton L. Smith
Ifigenia Geornaras
Mahesh N. Nair
author_facet Colton L. Smith
Ifigenia Geornaras
Mahesh N. Nair
author_sort Colton L. Smith
collection DOAJ
description There is limited understanding of the relationship between the growth of spoilage microflora and fresh meat color. Therefore, the objective of this study was to investigate the impact of the growth of common spoilage bacteria on the color stability of color-stable (longissimus lumborum; LL) and color-labile (psoas major; PM) beef muscles. Beef striploins (LL) and tenderloins (PM) (USDA Choice, n = 8) were wet aged (14 d), after which they were decontami- nated and fabricated into 1.27-cm thick steaks. Steaks were randomly assigned as decontaminated (DCON) or inoculated (INOC). The surface of INOC steaks was inoculated (ca. 4 log CFU/cm 2 ) with a mixture of spoilage bacteria, while an equivalent volume of phosphate-buffered saline was applied to the surface of DCON steaks. Steaks were aerobically retail displayed for up to 9 d. Each day, objective and subjective color evaluation and microbiological analyses were conducted. Aerobic plate counts on INOC steaks were 8.9 (LL) and 9.3 (PM) log CFU/cm 2 at the end of retail display. Corresponding counts on DCON steaks were < 2.7 (LL) and < 3.4 (PM) log CFU/cm2. For LL steaks, there was a treatment × display day interaction (P < 0.05) for lightness (L* ), redness (a*), yellowness (b*), lean color scores, surface discoloration, and bac- terial levels. On days 6 – 8, redness was lower (P < 0.05) for INOC compared to DCON LL steaks, while lean color scores and surface discoloration were lower (P < 0.05) for DCON compared to INOC LL steaks. For PM, there was a treatment × display day interaction (P < 0.05) for a* values, surface discoloration, and bacterial levels. Surface discoloration was greater (P < 0.05) for INOC steaks compared with DCON steaks on days 4 and 5. The results indicate a connection between surface discoloration and microbial growth on beef LL and PM steaks, and differences in bacterial growth kinetics could explain some of the differential color stabilities between these muscles.
format Article
id doaj-art-41cbad30e6ca433b8097b18a61c0182b
institution DOAJ
issn 2575-985X
language English
publishDate 2024-09-01
publisher Iowa State University Digital Press
record_format Article
series Meat and Muscle Biology
spelling doaj-art-41cbad30e6ca433b8097b18a61c0182b2025-08-20T03:10:57ZengIowa State University Digital PressMeat and Muscle Biology2575-985X2024-09-018110.22175/mmb.17796Impact of Spoilage Bacterial Populations on Discoloration of Beef SteaksColton L. Smith0Ifigenia Geornaras1Mahesh N. Nair2https://orcid.org/0000-0002-2917-1028Texas Tech UniversityAnimal Science, Colorado State UniversityDepartment of Animal Sciences, Colorado State UniversityThere is limited understanding of the relationship between the growth of spoilage microflora and fresh meat color. Therefore, the objective of this study was to investigate the impact of the growth of common spoilage bacteria on the color stability of color-stable (longissimus lumborum; LL) and color-labile (psoas major; PM) beef muscles. Beef striploins (LL) and tenderloins (PM) (USDA Choice, n = 8) were wet aged (14 d), after which they were decontami- nated and fabricated into 1.27-cm thick steaks. Steaks were randomly assigned as decontaminated (DCON) or inoculated (INOC). The surface of INOC steaks was inoculated (ca. 4 log CFU/cm 2 ) with a mixture of spoilage bacteria, while an equivalent volume of phosphate-buffered saline was applied to the surface of DCON steaks. Steaks were aerobically retail displayed for up to 9 d. Each day, objective and subjective color evaluation and microbiological analyses were conducted. Aerobic plate counts on INOC steaks were 8.9 (LL) and 9.3 (PM) log CFU/cm 2 at the end of retail display. Corresponding counts on DCON steaks were < 2.7 (LL) and < 3.4 (PM) log CFU/cm2. For LL steaks, there was a treatment × display day interaction (P < 0.05) for lightness (L* ), redness (a*), yellowness (b*), lean color scores, surface discoloration, and bac- terial levels. On days 6 – 8, redness was lower (P < 0.05) for INOC compared to DCON LL steaks, while lean color scores and surface discoloration were lower (P < 0.05) for DCON compared to INOC LL steaks. For PM, there was a treatment × display day interaction (P < 0.05) for a* values, surface discoloration, and bacterial levels. Surface discoloration was greater (P < 0.05) for INOC steaks compared with DCON steaks on days 4 and 5. The results indicate a connection between surface discoloration and microbial growth on beef LL and PM steaks, and differences in bacterial growth kinetics could explain some of the differential color stabilities between these muscles.https://www.iastatedigitalpress.com/mmb/article/id/17796/meat colormeat spoilagemicrobial growthshelf-lifefresh beef
spellingShingle Colton L. Smith
Ifigenia Geornaras
Mahesh N. Nair
Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks
Meat and Muscle Biology
meat color
meat spoilage
microbial growth
shelf-life
fresh beef
title Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks
title_full Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks
title_fullStr Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks
title_full_unstemmed Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks
title_short Impact of Spoilage Bacterial Populations on Discoloration of Beef Steaks
title_sort impact of spoilage bacterial populations on discoloration of beef steaks
topic meat color
meat spoilage
microbial growth
shelf-life
fresh beef
url https://www.iastatedigitalpress.com/mmb/article/id/17796/
work_keys_str_mv AT coltonlsmith impactofspoilagebacterialpopulationsondiscolorationofbeefsteaks
AT ifigeniageornaras impactofspoilagebacterialpopulationsondiscolorationofbeefsteaks
AT maheshnnair impactofspoilagebacterialpopulationsondiscolorationofbeefsteaks