Hafnia alvei is a psychrotrophic strain, which can develop at low temperatures, meaning that it doesn't stop growing during the storage phase of cheese unlike E.

A few years later, in 1987, Hafnia alvei was identified by a Spanish team in raw ewes' milk representing 6.5% of the total Enterobacterales species present.

Hafnia alvei has also been identified in commercial kimchi, a traditional Korean meal made with Asian cabbage, radish, spices and salted fermented seafood.

[13] In 2004, Mexican scientists isolated Hafnia alvei (among other bacteria such as Lactobacillus acidophilus or plantarum) from pulque a traditional beverage made from fermented Maguey (also known as agave).

[15] Fermented sausages made in Spain were also reported to contain the Hafnia alvei strain, responsible for producing histamine that is crucial to the ripening process.

[16] Most standard microbiology texts list mammals, birds, reptiles, fish, soil, water, sewage, and foods as sources from which hafniae can be recovered.

Paleomicrobiology investigations have identified H. alvei originating from intestinal mass samples and sediment collected from 12,000-year-old mastodon remains in Michigan and Ohio.

In a study of 642 Australian mammals, Gordon and FitzGibbon[17] found that H. alvei was the third most common enteric species identified, following Escherichia coli and E. cloacae.

Hafniae have also been recovered sporadically from the manure samples of pack animals collected from national park trails and from 7% of the grizzly and black bear specimens tested.

Several researchers estimated that the level of H. alvei reaches 107 CFU/g at the end of ripening process and showed that its growth curve is closely linked to an increase in pH.

A 2013 study of a cheese model ecosystem highlighted the role of Hafnia alvei in inhibiting the growth of E. coli strain O26:H11 without altering pH or lactic acid concentrations.

Hafnia alvei did produce a small amount of biogenic amines such as putrescine and cadaverine but these didn't affect the overall level of volatile aroma compounds.

[4] There is general agreement that almost 100% of Hafnia strains grow on MacConkey, Hektoen enteric, eosin methylene blue, and xylose-lysine-deoxycholate agars, all of which are differential to moderately selective media.

[22] On more inhibitory selective media, 25% to 60% of strains fail to grow on Salmonella-Shigella (SS) agar, while 75% to 100% of isolates are inhibited on brilliant green medium.

On moderately selective agars, they typically appear as large, smooth, convex, translucent colonies of 2 to 3 mm in diameter with an entire edge; some may exhibit an irregular border.

This is likely due to the low occurrence frequency of this species in human illnesses and the fact that there are no clear-cut disease syndromes specifically associated with H. alvei.

[5] H. alvei is an uncommon human pathogen despite the increased attention from the medical community over the past decade due to its possible association with gastroenteritis.

There are no well-described outbreaks of disease caused by H. alvei in which the epidemiologic, clinical, and laboratory correlates are overwhelmingly in support of an unquestionable role for hafniae in these illnesses.

The general pattern that emerges from this study is that hafniae are typically susceptible to carbapenems, monobactams, chloramphenicol, quinolones, aminoglycosides, and antifolates (e.g., trimethoprim-sulfamethoxazole) and resistant to penicillin, oxacillin, and amoxicillin plus clavulanic acid.

[29] Hafnia produces a protein called Caseinolytic Protease B (ClpB) which has been shown to be a mimetic of the hormone α-MSH which is implicated in satiety.

[34] TargEDys,[35] a French company, which demonstrated that the Hafnia alvei HA4597 strain could stimulate satiety via the ClpB protein and help to naturally control appetite and lose weight, conducted the studies enabling the marketing of this probiotic.