Spore germination of the psychrotolerant, red meat spoiler, Clostridium frigidicarnis

Abstract

Aims: To determine germination triggers of Clostridium frigidicarnis, an important spoilage bacterium of chilled vacuum‐packed meat. Methods and Results: Germination of Cl. frigidicarnis spores in the presence of a range of potential nutrient and non‐nutrient germinants was tested by monitoring the fall in optical density and by phase‐contrast microscopy. The amino acid l‐valine induced strong germination when paired with l‐lactate in sodium phosphate under anaerobic conditions. Several other amino acids promoted germination when paired with l‐lactate in sodium phosphate and the co‐germinants NaHCO3 and l‐cysteine. Heat activation, while not necessary for germination, increased the rate of germination. Spore germination was not observed when spores were incubated aerobically. Conclusions: Spores of psychrotolerant Cl. frigidicarnis germinated in the presence of l‐valine in combination with l‐lactate in sodium phosphate buffer under anaerobic conditions. Significance and Impact of the Study: Anaerobic conditions, l‐valine and l‐lactate, have been identified as triggering germination in Cl. frigidicarnis, and are all present in packs of fresh, vacuum‐packaged, red meat. This new information adds to what is known about red meat spoilage by cold tolerant clostridia and can be used to develop intervention strategies to prevent meat spoilage.

Influence of different shrinking temperatures and vacuum conditions on the ability of psychrotrophic Clostridium to cause ‘blown pack’ spoilage in chilled vacuum-packaged beef

“…Along with C. estertheticum, C. gasigenes is recognized as the most frequent causative agents of 'blown pack' spoilage (Adam, Brunt, Brightwell, Flint, & Peck, 2011). Therefore, it should be highlighted that the presence of these microorganisms poses a risk for the stability of vacuum-packaged beef during chilled storage .…”

“…This is because several compounds or physical conditions may act as germination triggers. Recently, Adam et al (2011) have reported that in anaerobic conditions, L-valine and L-lactate are the main triggers for germination of spores of C. frigidicarnis, which are compounds found in vacuum-packaged beef. Additionally, it is important to take into account that the D values of spores of pyschrotrophic Clostridium are between 12 and 94 min at 85°C , therefore, the main event that occurred seems to be the inactivation of vegetative cells rather than the germination of spores, which explains the delay in the occurrence of 'blown pack' spoilage when the shrinking temperature was increased.…”

Germinants and Their Receptors in Clostridia

“…Toward this requirement, C. frigidicarnis and spores derived from nonfoodborne C. perfringens strains germinate in response to the branched-chain amino acid L-valine (norvaline could also be used by C. frigidicarnis and C. difficile) (34,57,58). L-Valine is a precursor to lipid biosynthesis, and thus, L-valine could be used as a metric to sense the ability to produce cell membrane from the surrounding environment.…”

IDENTIFICAÇÃO DE PONTOS DE CONTAMINAÇÃO POR Clostridium estertheticum EM AMBIENTES MATADOUROS FRIGORÍFICOS

“…O procedimento de retirada do couro, através da utilização do rolete, é considerado por BRODA et al (2002) Os resultados de maior positividade obtidos neste estudo para os pontos de coleta classificados como "Câmaras Frigoríficas" e "Sala de Desossa", estão de acordo com os resultados obtidos por BRODA et al (2002) e podem ser relacionados ao fato do C. estertheticum ser um micro-organismo telúrico e, ao mesmo tempo psicrofílico, estando, portanto, vinculado ao meio onde é naturalmente encontrado, evidenciando sua presença em superfícies com maior possibilidade de contaminação pelo solo e fezes e que apresentam maior grau de dificuldade para a realização das operações de limpeza e sanitização. Ressalta-se, entretanto, que a falta de controle da temperatura ideal nas salas de desossa (<15°C) e câmaras frigoríficas (<5°C) como verificado por ADAM et al (2013), associadas à condição de anaerobiose dos cortes cárneos embalados a vácuo, propiciam condições ideais para que o micro-organismo assuma a forma vegetativa e se multiplique (ADAM et al, 2011).…”