The presence of H2 is indicated in the chromatogram by a positive peak and CO2 by a negative peak at the end of the chromatogram. Another negative peak often found at the rear of the hydrogen peak is caused by a change in the gas composition in the headspace vials. Aerobic and facultative anaerobic bacteria consume oxygen to produce CO2 and thus the oxygen concentration of ambient air in the headspace gas of the closed vials is reduced and the nitrogen concentration is thus enhanced. This altered gas sample, withdrawn for analysis, has a lower heat conductivity compared with the ambient air used as carrier gas. A negative peak is thus created from the oxygen deficit, which corresponds to the retention time of air on this GC column. The missing oxygen however is not lost but transferred to CO2, with the corresponding negative CO2 peak at the end of the chromatogram. The chromatograms were obtained using either a GC-column with Silicagel or alternatively with Chromosorb 102. The latter GC-column separates the negative peak of the O2- deficit slightly better from the rear of the H2 peak, but CO2 on the other hand has a longer retention time. However, since these negative peaks may also be caused by CO2 resulting from some oxidation of other compounds in the sample or in the nutrient medium, both negative peaks are not significant for bacteria and are in general not used for this analysis, while the emission of H2 is caused unambiguously by bacteria contrary to the insecurity of the origin of the CO2 emission. presents the various chromatographic patterns with positive and negative peaks and the agreement of a resulting H2 peak with the H2 sensor response.
Author(s) Details:
Bruno Kolb
Student Research Centre, Überlingen, Obertorstrasse, Germany.
Recent Global Research Developments in Bacterial Infection of Food
Genome-Based Approaches for Foodborne Pathogens: This review discusses how genome-based methods have advanced our understanding of the evolution and spread of bacterial foodborne hazards. It highlights the role of whole-genome and metagenome sequencing in identifying and addressing risks in the food chain [1] .
Opportunistic Infections via Dietary Routes: This article focuses on opportunistic bacterial pathogens transmitted through contaminated food. It emphasizes the importance of hygiene in food production and consumer awareness to prevent infections, especially in individuals with underlying health conditions [2] .
Antimicrobial Resistance in the Food Chain: This study explores the presence of antimicrobial-resistant bacteria in the food chain. It underscores the need for better control measures to prevent the spread of these bacteria from farm to consumer [3] .
Bacterial Infections and Antibiotic Resistance: This article reviews the treatment of bacterial infections and the growing issue of antibiotic resistance. It discusses the implications for food safety and public health [4] .
Emerging Threats in Foodborne Illnesses: This review highlights the emerging threats posed by foodborne bacterial pathogens in a changing world. It examines the impact of climate change, food sustainability targets, and evolving consumer preferences on the ecology of foodborne pathogens [1] .
References
- Mather, A.E., Gilmour, M.W., Reid, S.W.J. et al. Foodborne bacterial pathogens: genome-based approaches for enduring and emerging threats in a complex and changing world. Nat Rev Microbiol 22, 543–555 (2024). https://doi.org/10.1038/s41579-024-01051-z
- Rossi F, Santonicola S, Amadoro C, Marino L, Colavita G. Recent Records on Bacterial Opportunistic Infections via the Dietary Route. Microorganisms. 2024; 12(1):69. https://doi.org/10.3390/microorganisms12010069
- Samtiya M, Matthews KR, Dhewa T, Puniya AK. Antimicrobial Resistance in the Food Chain: Trends, Mechanisms, Pathways, and Possible Regulation Strategies. Foods. 2022; 11(19):2966. https://doi.org/10.3390/foods11192966
- Bacterial Infections, Treatment and Antibiotic Resistance
https://www.mdpi.com/journal/life/topical_collections/bacterial
