The effect of colony formation on the heat inactivation dynamics of Escherichia coli K12 and Salmonella typhimurium

Velliou, Eirini; Noriega, Estefanía; Derlinden, Eva Van; Mertens, Laurence; Boons, Kathleen; Devlieghere, Frank; Impe, Jan Van

doi:10.1016/j.foodres.2013.09.009

Cited by 27 publications

(38 citation statements)

References 25 publications

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“…Secondly, the bacteria were constrained to grow as colonies. In Velliou et al (2013) it was shown how E. coli K12 and Salmonella Typhimurium, grown as colonies of various sizes in a matrix gelled with xanthan gum, display a higher thermal resistance when compared with planktonic cells. The surviving L. monocytogenes after pan-frying may be a potential risk for food safety.…”

Section: Discussionmentioning

confidence: 99%

Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying

et al. 2015

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Ground pork meat with natural microbiota and inoculated with low initial densities (1–10 or 10–100 CFU/g) of Salmonella enterica or Listeria monocytogenes was stored under abusive temperature at 10°C and thermally treated by a simulated home pan-frying procedure. The growth and inactivation characteristics were also evaluated in broth. In ground pork meat, the population of S. enterica increased by less than one log after 12-days of storage at 10°C, whereas L. monocytogenes increased by 2.3 to 2.8 log units. No unusual intrinsic heat resistance of the pathogens was noted when tested in broth at 60°C although shoulders were observed on the inactivation curves of L. monocytogenes. After growth of S. enterica and L. monocytogenes at 10°C for 5 days to levels of 1.95 log CFU/g and 3.10 log CFU/g, respectively, in ground pork meat, their inactivation in the burger subjected to a simulated home pan-frying was studied. After thermal treatment S. enterica was undetectable but L. monocytogenes was recovered in three out of six of the 25 g burger samples. Overall, the present study shows that data on growth and inactivation of broths are indicative but may underestimate as well as overestimate behavior of pathogens and thus need confirmation in food matrix conditions to assess food safety in reasonably foreseen abusive conditions of storage and usual home pan-frying of meat burgers in Belgium.

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Section: Discussionmentioning

confidence: 99%

Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying

et al. 2015

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“…Additionally, in co‐culture systems the spatial organization, colony size, and location of each species can affect their inter‐and intra‐species interaction and communication, which will directly affect the environmental stress within a colony, affecting the growth kinetics of both the pathogen and the naturally present bacteria . Overall, microorganisms could display a different level of AMR development due to environmental stress adaptation and cross protection …”

Section: Introductionmentioning

confidence: 99%

A multi‐scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co‐culture systems

et al. 2019

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Natural antimicrobials are of interest to replace traditional food decontamination methods: they are milder and maintain desirable sensory characteristics. However, efficacy can be affected by food structure/composition, thus structural effects in a co-culture pathogen/microflora system are investigated. Listeria was grown planktonically (liquid broth) or on a biphasic viscoelastic system, in monoculture with/without artificial nisin, or in co-culture with Lactococcus lactis (nisin/non-nisin producing). Microbial growth kinetics were monitored and advanced microscopy techniques were utilized to quantify cellular interactions and spatial organization. Microstructural effects are observed on the kinetics, with differences in monoculture/co-culture. Significant microscopic differences are observed in spatial organization and colony size. We are the first to observe changing growth location for all species in monoculture/co-culture, with differences in colony size/organization through stationary phase. This study provides insight into the environmental stress response/adaptation of Listeria grown on structured systems in response to L. lactis and natural antimicrobials.

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“…Studies of growth of LAB in the liquid milk (Favrot and Maubois, 1994 , 1996 ; Letort et al, 2002 ) and solid cheese are complicated because traditional microbiological methods are not well suited for the enumeration of bacteria in opaque and especially in solid media. Peculiarities of colonial growth of bacteria in solid transparent matrices (agar, gelatine) have been described, however, in several papers (Brocklehurst et al, 1995 ; McKay et al, 1997 ; Malakar et al, 2002 ; Wilson et al, 2002 ; Kabanova et al, 2009 , 2012 ; Velliou et al, 2013 ). Studies of growth of LAB in solid coagulated milk samples are clearly less numerous (Favrot and Maubois, 1996 ; Floury et al, 2010 , 2013 ; Jeanson et al, 2011 ).…”

Section: Introductionmentioning

confidence: 99%

Microcalorimetric study of the growth of Streptococcus thermophilus in renneted milk

et al. 2015

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The growth of Streptococcus thermophilus ST12 (ST12) in liquid milk, reconstituted from low-heat skim milk powder reconstituted skim milk (RSM) and in RSM with rennet addition (r-RSM) at 40°C was monitored by microcalorimetry. It was shown that the growth rate of bacteria decreased in renneted samples in comparison with liquid RSM starting from certain sizes of the colonies (“deviation moments”), which depended on the inoculation rates. The hydrolysis of lactose was delayed for about 1 h in the r-RSM in comparison with RSM but otherwise the metabolism of carbohydrates in the renneted and non-renneted milks was similar. The total free amino acids (TFAA) content by the end of fermentations was higher in r-RSM than in RSM presumably due to the enzymatic hydrolytic activity of rennet. The quantitatively dominating amino acids were remarkably different in the r-RSM and RSM indicating that the hydrolysis cascade of caseins and/or metabolism of amino acids by the bacteria functioned differently in the two cases. The data obtained showed potential of microcalorimetry to characterize quantitative differences of growth and metabolism of the bacteria in renneted and liquid samples of milk.

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The effect of colony formation on the heat inactivation dynamics of Escherichia coli K12 and Salmonella typhimurium

Cited by 27 publications

References 25 publications

Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying

Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying

A multi‐scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co‐culture systems

Microcalorimetric study of the growth of Streptococcus thermophilus in renneted milk

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