Skip to main content
ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Poultry Microbiological Safety and Processing Research Unit » Research » Publications at this Location » Publication #419847
Research Project: Alternatives to Antibiotics and Genomics of Antimicrobial Resistance to Control Foodborne Pathogens in Poultry

Location: Poultry Microbiological Safety and Processing Research Unit

Title: Hydrogen sulfide negative Salmonella and their implication for standard culture-based identification: looking at the other side of the coin

Author
item BENTUM, KINGSLEY - Tuskegee University
item KUUFIRE, EMMANUEL - Tuskegee University
item NYARKU, REJOICE - Tuskegee University
item SAMUEL, TEMESGEN - Tuskegee University
item Jackson, Charlene
item ABEBE, WOUBIT - Tuskegee University

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/25/2025
Publication Date: 5/30/2025
Citation: Bentum, K., Kuufire, E., Nyarku, R., Samuel, T., Jackson, C.R., Abebe, W. 2025. Hydrogen sulfide negative Salmonella and their implication for standard culture-based identification: looking at the other side of the coin. Journal of Food Protection. https://doi.org/10.1016/j.jfp.2025.100549.
DOI: https://doi.org/10.1016/j.jfp.2025.100549

Interpretive Summary: Salmonella is a bacterial pathogen capable of causing disease in humans and animals. Colonies of Salmonella commonly produce hydrogen sulfide gas observed as a black precipitate due to the reaction of the gas with ferric ammonium present in many Salmonella selective culture media. This property of the pathogen is part of routine Salmonella detection in diagnostic laboratories. Several concerns have been raised about the possibility of these serovars eluding current isolation methods. This review discusses the reason for this variation including current isolation protocols and suggestions to improve the detection of these serovars. These atypical Salmonella, which have been associated with foodborne outbreaks, may continue to emerge as more isolation and testing is performed. Since culture-based methods to characterize Salmonella remain in use for the foreseeable future, phenotype-based techniques that rely on hydrogen sulfide production to detect the pathogen need to be carefully implemented or revised. This information is important for microbiologists in diagnostic or research labs to raise awareness of the existence and continuous circulation of these atypical serovars.

Technical Abstract: Salmonella is a ubiquitous zoonotic pathogen capable of causing disease in humans and animals. With over 2,500 serovars, Salmonella represents one of the most diverse bacterial populations. Colonies of Salmonella commonly produce hydrogen sulfide (H2S) gas, evident (visible) as a black precipitate due to the reaction of the gas with ferric ammonium contained in most Salmonella selective culture media. This property of the pathogen is part of routine Salmonella detection in diagnostic laboratories. Recently, some H2S-negative Salmonella serovars have been identified which are also as pathogenic as the H2S-producing serovars. Several concerns have also been raised about the possibility of these serovars eluding current isolation protocols. This article discusses the reason for this phenotypic variation, implications for missing them considering current isolation protocols, and makes suggestions to improve the detection of these serovars. It is part of efforts to raise awareness of the existence and continuous circulation of these serovars and their potential pathogenicity.