Dataset Information

Quantitative Oxygen Consumption and Respiratory Activity of Meat Spoiling Bacteria Upon High Oxygen Modified Atmosphere.

ABSTRACT: High oxygen modified atmosphere packaging is a commonly applied method to prolong the minimum shelf life of fresh (red) meats. Upon spoilage, changes of the initial oxygen concentration and microbiome composition can be observed. Thus, we classified the typical representative meat spoiling bacteria Brochothrix (B.) thermosphacta TMW2.2101 and the four lactic acid bacteria (LAB) Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618, and L. gelidum subsp. gasicomitatum TMW2.1619 along their oxygen consuming capacity, which can indicate the timeline of microbiome and sensorial changes. All bacteria were grown in a model system employing gas tight glass bottles containing meat simulation media and under modified atmosphere (70% O2 and 30% CO2). Oxygen concentrations of media and headspaces were monitored over time and the oxygen uptake rate (OUR) was calculated for all species. All bacteria were able to consume dissolved oxygen, with B. thermosphacta TMW2.2101 exhibiting a 31-times higher OUR per single cell in 60 h. Furthermore, all strains showed significant growth enhancement in the presence of heme indicating respiratory activity. Comparative genomic and physiological analyses predict the activity of a respiratory chain for all species upon high oxygen atmosphere. An additional cytochrome aa3 oxidase is suggested to be responsible for the increased OUR of B. thermosphacta TMW2.2101. Furthermore, B. thermosphacta TMW2.2101 revealed highest oxidative stress tolerance compared to the other bacteria, facilitating a higher respiratory activity. Coupling of respiration and fermentation via regeneration of NADH can be a competitive advantage for meat spoiling bacteria resulting in a higher cell count and possibly accelerated spoilage. The exhibited highest capacity for oxygen consumption of B. thermosphacta compared to LAB in vitro also suggests a higher contribution of this bacterium to the change in the atmosphere upon spoilage of MAP meats in situ.

SUBMITTER: Kolbeck S

PROVIDER: S-EPMC6857183 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Quantitative Oxygen Consumption and Respiratory Activity of Meat Spoiling Bacteria Upon High Oxygen Modified Atmosphere.

Kolbeck Sandra S Reetz Leonie L Hilgarth Maik M Vogel Rudi F RF

Frontiers in microbiology 20191108

High oxygen modified atmosphere packaging is a commonly applied method to prolong the minimum shelf life of fresh (red) meats. Upon spoilage, changes of the initial oxygen concentration and microbiome composition can be observed. Thus, we classified the typical representative meat spoiling bacteria Brochothrix (B.) thermosphacta TMW2.2101 and the four lactic acid bacteria (LAB) Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, ...[more]

PMID: 31781049

Similar Datasets

Project description:Oxygen and carbon dioxide are common protective gases used in modified atmosphere packaging (MAP) of meat. Within the package, they selectively suppress members of the spoilage microbiome, reshaping it to adapted species concomitantly growing upon MAP. Thus, this species must exhibit adaptation mechanisms to withstand the inhibitory effect of carbon dioxide and oxygen, and cope with selective nutrition on MAP meat. In order to uncover these mechanisms, the typical representative meat-spoiling bacteria Brochothrix (B.) thermosphacta TMW2.2101 and four lactic acid bacteria (LAB) Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618 and L. gelidum subsp. gasicomitatum TMW2.1619 were grown in a meat simulation medium under a controlled, sterile environment, aerated constantly with either air, 100%_N2, 30%_CO2/70%_O2 or 30%_CO2/70%_N2. Growth dynamics were monitored and a label-free quantitative mass spectrometric approach was employed to determine changes within the bacterial proteomes in response to the different gas atmospheres. Revealed bacterial tolerance to modified atmospheres (MA) comprise two possible scenarios: Either bacteria were intrinsically adapted to MA, exhibiting no proteomic regulation of enzymes (L. gelidum subsp. gelidum and gasicomitatum) or, tolerance was provided by varying specific metabolic adaptation (B. thermosphacta, C. divergens, C. maltaromaticum). In detail, metabolic adaptation mechanisms to oxygen comprised an enhanced oxidative stress reduction response, adjustment of the pyruvate metabolism and catabolic oxygen consuming reactions. Adaptation to carbon dioxide was characterized by an upregulation of proteins involved in intracellular pH homeostasis, maintenance of osmotic balance and alteration of the fatty acid composition of the cell membrane. We furthermore predict species-specific strategies for different and preferential carbon source utilization enabling a non-competitive coexistence on meat and resulting in a synergistic spoilage. We conclude that a gas atmosphere containing 30%_CO2/70%_O2 has no inhibitory effect on the analyzed prominent meat-spoiling bacteria whereas 30%_CO2/70%_N2 predictively inhibits C. divergens TMW21577 and B. thermosphacta TMW2.2101 but not the other three species. This gives a mechanistically explanation of their acknowledged status as typical spoilage organisms on packaged meats.

Project description:Besides intrinsic and extrinsic factors such as antagonism for organic substrates or temperature, the storage atmosphere of meat has a high influence on the development of its initial microbiota. Specific modified atmospheres (MAs) selectively suppress growth of aerobic and anaerobic bacteria, thus reshaping the initial microbiota. As some microorganisms are more tolerant to MA, they overgrow competitors and produce metabolites that cause rejection of the product. In order to elucidate responses to different MA by means of metabolic adaptation and competition for organic substrates on meat, the typical representative meat spoilage bacteria Brochothrix (B.) thermosphacta TMW2.2101 and four lactic acid bacteria Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618 and L. gelidum subsp. gasicomitatum TMW2.1619 were chosen. Bacteria were grown in sterile glass bottles filled with a meat simulation medium, which was aerated constantly with either air, 100%_N2, 30%_CO2/70%_O2 or 30%_CO2/70%_N2. Growth of bacteria during incubation at 25°C and stirring at 120 rpm was monitored over 48 h and a label-free quantitative mass spectrometric approach was employed to determine changes within the bacterial proteomes in response to oxygen and carbon dioxide. Both Leuconostoc subsp. were intrinsically tolerant to MA, exhibiting no proteomic regulation of enzymes, whereas the other species provide a set of metabolic adaptation mechanism, enabling higher resistance to the detrimental effects of MA. Those mechanisms comprise: enhanced oxidative stress reduction, adjustment of the pyruvate metabolism and catabolic oxygen consumption in response to oxygen and intracellular pH homeostasis, maintenance of osmotic balance and alteration of the fatty acid composition in response to carbon dioxide. We further evaluated the potential of industrial used MA to inhibit specific bacterial spoilage. No bacterial inhibition is predicted for 30%_CO2/70%_O2 for the analyzed species, whereas 30%_CO2/70%_N2 predictively inhibits C. divergens TMW21577 and B. thermosphacta TMW2.2101. Furthermore, species-specific metabolic pathways enabling different and preferential carbon source utilization were identified, which enable non-competitive coexistence of respective bacteria on meat, resulting in synergistic spoilage. In conclusion, this study gives mechanistically explanations of their acknowledged status as typical spoilage organisms on MAP meats.

Project description:The ability of certain Pseudomonas (P.) species to grow or persist in anoxic habitats by either denitrification, acetate fermentation, or arginine fermentation has been described in several studies as a special property. Previously, we had isolated strains belonging to the species P. lundensis, P. weihenstephanensis, and P. fragi from anoxic modified atmosphere packaged (MAP) minced beef and further proved their anaerobic growth in vitro on agar plates. This follow-up study investigated the anaerobic growth of two strains per respective species in situ on inoculated chicken breast filet under 100% N2 modified atmosphere. We were able to prove anaerobic growth of all six strains on chicken breast filet with cell division rates of 0.2-0.8/day. Furthermore, we characterized the anaerobic metabolic lifestyle of these Pseudomonas strains by comparative proteomics, upon their cultivation in meat simulation media, which were constantly gassed with either air or 100% N2 atmospheres. From these proteomic predictions, and respective complementation by physiological experiments, we conclude that the Pseudomonas strains P. fragi, P. weihenstephanensis, P. lundensis exhibit a similar anaerobic lifestyle and employ arginine fermentation via the arginine deiminase (ADI) pathway to grow anaerobically also on MAP meats. Furthermore, glucose fermentation to ethanol via the ED-pathway is predicted to enable long term survival but no true growth, while respiratory growth with nitrate as alternative electron acceptor or glucose fermentation to acetate could be excluded due to absence of essential genes. The citric acid cycle is partially bypassed by the glyoxylate shunt, functioning as the gluconeogenetic route without production of NADH2 under carbon limiting conditions as e.g., in packaged meats. Triggered by an altered redox balance, we also detected upregulation of enzymes involved in protein folding as well as disulfide bonds isomerization under anoxic conditions as a counteracting mechanism to reduce protein misfolding. Hence, this study reveals the mechanisms enabling anaerobic grow and persistence of common meat-spoiling Pseudomonas species, and further complements the hitherto limited knowledge of the anaerobic lifestyle of Pseudomonas species in general.

Dataset Information

Quantitative Oxygen Consumption and Respiratory Activity of Meat Spoiling Bacteria Upon High Oxygen Modified Atmosphere.

Publications

Quantitative Oxygen Consumption and Respiratory Activity of Meat Spoiling Bacteria Upon High Oxygen Modified Atmosphere.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets