Background: Salmonella enterica subsp. enterica serovar Muenster (antigenic formula 3,{10}{15}{15,34}:e,h:1,5) is a serovar of the O:3,10 (E1) serogroup. The serovars previously known as Newhaw and Arkansas are now classified as variants of serovar Muenster. Newhaw is designated as Muenster var. 15+ (converted by phage ε15), while Arkansas is Muenster var. 15+,34+ (converted by phages ε15 and ε34). These variants occupy the same serological position as group O:4 (B) strains, which express factor 1 upon conversion but had not been assigned new names. During 1986, Salmonella spp. (primarily serovar Muenster) was detected in 2.9% of raw milk samples from dairy herds in southwestern Ontario, but the prevalence declined to zero within approximately a year. According to the 1996 USDA prevalence study, serovar Muenster ranked as the seventh most frequent serotype, representing 4.7% of all Salmonella spp. isolates in US dairy operations. Serovar Muenster can cause abortion or diarrhea in cows in late gestation.
NCBI PD link for serovar Muenster: https://www.ncbi.nlm.nih.gov/pathogens/isolates/#(taxgroup_name:%22Salmonella%20enterica%22)%20AND%20computed_types:(%22serotype=Muenster%22)
Genetic characteristics: Chang et al. found an Muenster isolate with a 260-kb bla CTX-M-55-qnrS1-bearing IncHI2 plasmid. Argentinian researchers reported that serovar Muenster had low pathogenic potential in swine.
Animal reservoir: Dairy cattle is the reservoir for serovar Muenster. This serovar was also isolated from other animals such as pet bearded dragons, and birds (Tympanuchus cupido, Antigone canadensis).
Geographical distribution: According to the metadata from NCBI PD, serovar Muenster has been reported globally but primarily in US. Among a total of 2,659 serovar Muenster isolates available in NCBI PD (accessed 04/29/2025), there were 2,040 isolates collected in US.
Human outbreaks:
| Year | Location | Associated source | Number of cases |
|---|---|---|---|
| 2020 | US: multistate | Pet bearded dragons | 18 |
| 2008 | France | Goat's cheese | 25 |
| 2016 | US: multistate | Live poultry | 25 |
| 1980 | Saudi Arabia | Roast beef | 12 |
Border rejections:
Year | Exporting country | Importing country | Associated source | Product category |
| 2024 | Nigeria | Italy | Sesame seeds | Nuts, nut products and seeds |
| 2020 | Brazil | Germany | Black pepper | Herbs and spices |
| 2020 | Poland | Bulgaria | Frozen chicken leg quarters1 | Poultry meat and poultry meat products |
1 Salmonella Infantis and Muenster were found.
Recalls:
Year | Location | Associated source | Type |
| 2024 | Germany, Ireland | Tahini from Lebanon | Nuts, nut products and seeds |
Relevant links: