Genotypical and phenotypical characterization of Bacillus sporothermodurans strains, surviving UHT sterilisation

Characterization of Aerobic Spore-Forming Bacteria Isolated From Raw Milk, Skim Milk Powder and UHT Milk

“…isolates from UHT milk samples. Klijn et al (1997), Montanari et al (2004) demonstrated that B. sporothermodurans was the predominant sporigenous micro-organisms in UHT milk. Cosentino et al (1997) reported the presence of aerobic spore formers, including B. sphaericus, B. licheniformis and B. brevis, in Sardinian UHT milk samples.…”

“…are often present in raw milk and play an important role in the spoilage of UHT milk (Crielly et al, 1994).The use of Ultra-high-temperature (UHT) processing should inactivate the spores of Bacillus species and result in fluid milk products with a long shelf-life without refrigeration. However, defects in UHT milk product stability have been reported (Klijn et al, 1997). This nonstability appeared to be caused by the presence of highly heat-resistant bacterial endospores which were first detected in UHT milk from southern Europe in 1985 and were later identified in other countries both in and outside Europe (Hammer et al, 1995).…”

Genetic Heterogeneity in Bacillus sporothermodurans as Demonstrated by Ribotyping and Repetitive Extragenic Palindromic-PCR Fingerprinting

“…Several molecular methods have been used successfully to differentiate and characterize B. sporothermodurans strains, including PCR methods like random amplified polymorphic DNA analysis, repetitive extragenic palindromic (REP)-PCR, and 16S ribosomal DNA (rDNA) sequence analysis (12,18,20). All these techniques showed that the different B. sporothermodurans strains isolated so far from European UHT-treated and sterilized milk are phylogenetically very closely related, forming the so-called HRS clone, named after the initial description of this highly heat-resistant spore-forming organism (8).…”

“…REP-PCR has been recognized to be highly discriminatory for the differentiation of many bacterial species, including Escherichia coli and B. sporothermodurans (5,11,12,18). In addition, ribotyping has proved to be useful for differentiation at the subspecies level, as demonstrated for species like Pseudomonas aeruginosa, Vibrio cholerae, Listeria monocytogenes, and Clostridium botulinum (3,7,19,23).…”

Tracking spore-forming bacteria in food: From natural biodiversity to selection by processes

“…However, concerns about spore contamination in minimally processed or chilled food have increased over the past few years, as treated food may still contain viable spores that can germinate and outgrow during storage even at low temperature (Guinebretiere et al, 2003;Peck, 2006;Ranieri et al, 2009). Similarly, the emergence and description of highly heat resistant endospores (HRS) surviving commercial sterilisation and ultrahigh temperature (UHT) processing of milk have been isolated from UHT milk of several countries (Foschino et al, 1990;Klijn et al, 1997). In contrast with Bacillus sporothermodurans strains isolated from farm environment, strains isolated from heat-treated milk and characterised as HRS have been suggested to have a clonal origin, underlining the importance of environmental conditions encountered during sporulation on native spore resistance, survival and germination capacities (Brown, 2000;Nicholson et al, 2000;Nicholson and Law, 1999;Guillaume-Gentil et al, 2002;Scheldeman et al, 2002).…”