Further Studies on the Thermal Resistance of Streptococcus faecium and Streptococcus faecalis in Pasteurized Ham

Magnus, C. A.; McCurdy, A.R.; Ingledew, W. M.

doi:10.1016/s0315-5463(88)70778-6

Cited by 32 publications

(9 citation statements)

References 11 publications

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“…Even if widely used as probiotics for their ability to produce bacteriocins (enterocins) in fermented foods, some enterococci are also recognized of safety concern because they carry potential virulence factors and can display pathogenic traits (De Vuyst and others ). They are also among the most thermo‐tolerant of the nonspore forming bacteria (Sanz Perez and others ; Magnus and others ) and they are able to adapt to various substrates and growth conditions (low and high temperatures, extreme pH and salinities) (Moreno and others for review). Since populations around 3.2 log CFU/eggshell have been reported on the eggshell surface by Mallet and others (, ), their presence in pasteurized egg white may also be ascribed to cross‐contaminations at the step of egg breaking and to their remaining after the pasteurization process.…”

Section: Resultsmentioning

confidence: 99%

Microbial Quality of Industrial Liquid Egg White: Assumptions on Spoiling Issues in Egg‐Based Chilled Desserts

Techer

Daoud

Madec

et al. 2015

Journal of Food Science

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As a 1st step, this study aimed at investigating the microbial quality of liquid egg white in a French egg processing company. Thirty raw and 33 pasteurized liquid egg white samples were analyzed. Pasteurization was globally found efficient on mesophilic contaminants (1.7 ± 1.6 and 0.8 ± 0.9 log CFU/mL in raw and pasteurized samples, respectively), including for the control of Salmonella. However, Gram-positive enterococci were still detected in the pasteurized samples. As a 2nd step, a representative bacterial collection was built for exploring the spoilage issue in egg-based chilled desserts. Custard cream was chosen as growth medium since this food is widely used for the production of French chilled desserts. All of the 166 isolates of the bacterial collection were shown to be able to grow and to induce spoilage of the custard cream at refrigeration temperature (10 °C). Several spoilage types were highlighted in the custard cream, on the basis of changes regarding pH, consistency, production of holes or gas. As a 3rd step, bacterial enzymatic activities were explored on custard cream-based agar media. The bacterial collection was reduced to 43 isolates, based on further selection regarding the genera and the spoilage types previously highlighted. Albeit to different degrees, all these isolates were able to produce proteases. A large part of these isolates also expressed lipolytic and amylolytic activities. This study emphasizes the need to control egg white contamination and especially with Gram-positive heat-resistant Enterococi, in order to guarantee the shelf life of egg-based chilled desserts.

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Section: Resultsmentioning

confidence: 99%

Microbial Quality of Industrial Liquid Egg White: Assumptions on Spoiling Issues in Egg‐Based Chilled Desserts

Techer

Daoud

Madec

et al. 2015

Journal of Food Science

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“…Cells grown at 5°C (312 h), showed a similar thermotolerance than those grown at 40°C (5 h) and 45°C (4 h). Numerous workers have shown for several species of bacteria that stationary phase cells are more resistant than exponential phase cells (Hansen and Riemann 1963;Beuchat and Lechowich 1968;Magnus et al 1988;Cond on et al 1992;Kaur et al 1998;Pagán et al 1999). The structural and physiological changes that occur in this stage could be critical for the survival of the bacterial cell during heat exposure.…”

Section: Resultsmentioning

confidence: 99%

Thermal inactivation of Enterococcus faecium: effect of growth temperature and physiological state of microbial cells

Martínez

López

Bernardo

2003

Lett Appl Microbiol

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Aims: To provide data on the effects on culture temperature and physiological state of cells on heat resistance of Enterococcus faecium, which may be useful in establishing pasteurization procedures. Methods and Results: The heat resistance of this Ent. faecium (ATCC 49624 strain) grown at different temperatures was monitored at various stages of growth. In all cases, the bacterial cells in the logarithmic phase of growth were more heat sensitive. For cells which had entered in the stationary phase, D 70 values of 0AE53 min at 5°C, 0AE74 min at 10°C, 0AE83 min at 20°C, 0AE79 min at 30°C, 0AE63 min at 37°C, 0AE48 min at 40°C and 0AE41 min at 45°C were found. By extending the incubation times cells were more heat resistant as stationary phase progressed, although a different pattern was observed for cells grown at different temperatures. At the lower temperatures heat resistance increased progressively, reaching D 70 values of 1AE73 min for cells incubated at 5°C for 50 days and 1AE04 min for those grown at 10°C for 16 days. At other temperatures assayed heat resistance became stable for late stationary phase cells, reaching D 70 values of 1AE05, 1AE08 and 1AE01 min for cultures incubated at 20, 30 and 37°C. Heat resistance of cells obtained at higher temperatures, 40 and 45°C, was significantly lower, with D 70 values of 0AE76 and 0AE67 min, respectively. Neither the growth temperature nor the growth phase modified the z-values significantly. Conclusions: D 70 values obtained for Ent. faecium (ATCC 49624) varies from 0AE33 to 1AE73 min as a function of culture temperature and physiological state of cells. However, z values calculated were not significantly influenced by these factors. A mean value of 4AE50 ± 0AE39°C was found. Significance and Impact of the Study: Overall results strongly suggest that, to establish heat processing conditions of pasteurized foods ensuring elimination of Ent. faecium, it is advisable to take into account the complex interaction of growth temperature and growth phase of cells acting on bacterial thermal resistance.

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“…Heating of processed meats during production may confer a selective advantage to enterococci because these bacteria are among the most thermotolerant of the non-sporulating bacteria. After surviving the heat-processing step, enterococci have been implicated in spoilage of cured meat products, such as canned hams and chub-packed luncheon meats (Magnus et al, 1986(Magnus et al, , 1988. This is especially true where recontamination with competing bacteria is prevented, when products are heated after packaging in cans or in impermeable plastic films.…”

Section: Introductionmentioning

confidence: 99%

Occurrence and antibiotic resistance of enterococci in ready-to-eat food of animal origin

Chajęcka‐Wierzchowska¹,

Zadernowska²,

Nalepa³

et al. 2012

Afr. J. Microbiol. Res.

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The aim of this work was to determine which Enterococcus species could be isolated from food of animal origin and the significance of these enterococcal isolates according to their antibiotic resistance profiles. Ninety-two Enterococcus strains were isolated from retail food of animal origin in Olsztyn, Poland. They were classified as Enterococcus faecalis (44 strains), Enterococcus faecium (32 strains) or Enterococcus spp. (16 strains) by phenotypic method and confirmed by polymerase chain reaction (PCR). Susceptibility of these enterococcal strains to 15 selected antibiotics (ampicillin, penicillin G, gentamicin, streptomycin, vancomycin, teicoplanin, norfloxacin, levofloxacin, ciprofloxacin, tetracycline, tigecycline, rifampicin, nitrofurantoin, linezolid, fosfomycin, chloramphenicol and quinupristin/dalfopristin) was determined using the disk diffusion method according to the recommendations of Clinical and Laboratory Standards Institute (CLSI 2010, formerly NCCLS). All the investigated strains were sensitive to levofloxacin, ciprofloxacin and vancomycin. Antimicrobial susceptibility tests showed resistance phenotypes to a range of antibiotics widely administrated in humans such as tetracycline, nitrofurantoin and quinupristin/dalfopristin.

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Further Studies on the Thermal Resistance of Streptococcus faecium and Streptococcus faecalis in Pasteurized Ham

Cited by 32 publications

References 11 publications

Microbial Quality of Industrial Liquid Egg White: Assumptions on Spoiling Issues in Egg‐Based Chilled Desserts

Microbial Quality of Industrial Liquid Egg White: Assumptions on Spoiling Issues in Egg‐Based Chilled Desserts

Thermal inactivation of Enterococcus faecium: effect of growth temperature and physiological state of microbial cells

Occurrence and antibiotic resistance of enterococci in ready-to-eat food of animal origin

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