scholarly journals Determination of D and z values for Salmonella Typhimurium inoculated in an egg-based pastry

2020 ◽  
Vol 23 ◽  
Author(s):  
Márcio Moura-Alves ◽  
Carolina Machado ◽  
Cristina Saraiva ◽  
José A. Silva
Keyword(s):  
Salmonella Typhimurium ◽  
Chemical Characterization ◽  
Thermal Treatments ◽  
Salmonella Spp ◽  
E Coli ◽  
Physico Chemical ◽  
Egg Yolks ◽  
D Values ◽  
And Staphylococcus Aureus

Abstract Eggs, often used in pastry products, are one of the major transmission vehicles of Salmonella. The main purpose of this study was to evaluate Salmonella Typhimurium thermal resistance, by D and z values determination, in a traditional Portuguese egg-based pastry and its microbial and physical-chemical characterization. Salmonella Typhimurium ATCC 14028 (OXOID C6000L) (Ca. 1.33×108 cfu g-1) was inoculated in a liquid batter consisting of 8 whole eggs, 7 egg yolks, 280 g of wheat flour and 250 g of sugar. D and z values determinations were performed after applying a water bath to vacuum-packed samples of liquid batter (5 g), following thermal treatments: 52 °C (45, 90, 135, 180 and 225 min); 55 °C (15, 30, 45, 60, 70 and 80 min); 58 °C (5, 10, 15, 20, 25 and 30 min) and 61 °C (1, 2, 3, 4 and 5 min). Physico-chemical (aw, pH, moisture, sugar, ashes, protein and free fat) and microbiological determinations (mesophilic microorganisms, psychrotrophic, molds and yeasts, Enterobacteriacea, E. coli; Salmonella spp., Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) were also conducted in raw liquid batter. It was possible to investigate different combinations of time and temperature for Salmonella Typhimurium inactivation, compared to other studies on egg-based batter, often used to make pastry products. Liquid batter aw before inoculation was 0.94 and pH 7.26. The D values were obtained 53.19 min, 20.45 min, 6.95 min and 1.60 min, at 52 °C, 55 °C, 58 °C e 61 °C, respectively. From the calculated D values, the corresponding z value was 5.96 °C.

Fate of Pathogens Inoculated onto Vacuum-Packaged Sliced Hams to Simulate Contamination During Packaging1

1979 ◽  
Vol 42 (6) ◽  
pp. 464-469 ◽  
Author(s):  
M. E. STILES ◽  
L.-K. NG
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Bacillus Cereus ◽  
Clostridium Perfringens ◽  
Subsequent Treatment ◽  
Vacuum Packaging ◽  
E Coli ◽  
Survival And Growth ◽  
And Staphylococcus Aureus

Ham and chopped ham from two manufacturers were contaminated with five enteropathogens: Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus, at time of slicing and vacuum-packaging, to simulate contamination by manufacturer. Subsequent treatment of the samples, representing sound and undesirable retail handling and consumer use conditions, indicated marked differences in the fate of the pathogens between these products and within product type between the two manufacturers. Greatest differences were observed between the chopped ham products. All pathogens, except C. perfringens, grew actively in fresh ham and chopped ham with abusive holding at 30 and 21 C. After storage at 4 or 10 C for 30 days, B. cereus and C. perfringens were no longer detected, even after subsequent holding at 30 or 21 C for 24 h. E. coli survival and growth was variable, S. typhimurium survived well and grew under some conditions and S. aureus was generally inhibited at high levels of competition.

scholarly journals Choice of sterilizing/disinfecting agent: determination of the Decimal ReductionTime (D-Value)

2009 ◽  
Vol 45 (4) ◽  
pp. 701-708 ◽  
Author(s):  
Priscila Gava Mazzola ◽  
Angela Faustino Jozala ◽  
Letícia Célia de Lencastre Novaes ◽  
Patricia Moriel ◽  
Thereza Christina Vessoni Penna
Keyword(s):  
Medical Devices ◽  
Cross Contamination ◽  
Decimal Reduction Time ◽  
E Coli ◽  
Health Care Unit ◽  
Sodium Dichloroisocyanurate ◽  
D Values ◽  
Spread Of Infection ◽  
Disinfectant Efficacy

Efforts to diminish the transmission of infections include programs in which disinfectants play a crucial role. Hospital surfaces and medical devices are potential sources of cross contamination, and each instrument, surface or area in a health care unit can be responsible for spread of infection. The decimal reduction time was used to study and compare the behavior of selected strains of microorganisms. The highest D-values for various bacteria were obtained for the following solutions: (i) 0.1% sodium dichloroisocyanurate (pH 7.0) - E. coli and A. calcoaceticus (D = 5.9 min); (ii) sodium hypochlorite (pH 7.0) at 0.025% for B. stearothermophilus (D = 24 min), E. coli and E. cloacae (D = 7.5 min); at 0.05% for B. stearothermophilus (D = 9.4 min) and E. coli (D = 6.1 min). The suspension studies were an indication of the disinfectant efficacy on a surface. The data in this study reflect the formulations used and may vary from product to product. The expected effectiveness from the studied formulations shows that the tested agents can be recommended for surface disinfection as stated in present guidelines and emphasize the importance and need to develop routine and novel programs to evaluate product utility.

scholarly journals Determination of Salmonella spp., E. coli VTEC, Vibrio spp., and Norovirus GI-GII in Bivalve Molluscs Collected from Growing Natural Beds in Sardinia (Italy)

Foods ◽  
2017 ◽  
Vol 6 (10) ◽  
pp. 88 ◽  
Author(s):  
Marta Marceddu ◽  
Sonia Lamon ◽  
Simonetta Consolati ◽  
Sara Ciulli ◽  
Roberta Mazza ◽  
...  
Keyword(s):  
Bivalve Molluscs ◽  
Salmonella Spp ◽  
E Coli ◽  
Vibrio Spp

scholarly journals Comparative bacteriological analysis of frozen and fresh chicken meats sold around old site Bayero University Kano

2021 ◽  
Vol 14 (1) ◽  
pp. 258-262
Author(s):  
Habibu Usman Abdu ◽  
Aisha Mustapha Abubakar
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Species ◽  
Bacterial Count ◽  
Chicken Meat ◽  
Salmonella Spp ◽  
E Coli ◽  
Meat Samples ◽  
And Staphylococcus Aureus ◽  
Klebsiella Spp ◽  
Campylobacter Spp

Foodborne pathogens are serious public healthproblems that greatly affect the cost of food production and healthcare while poultry are often associated with foodborne disease outbreaks. This study aimed at investigating the occurrence and distribution of bacterial pathogens associated with chicken meats sold around Bayero University, Kano old site. A total of twenty (20) meat samples comprised of 10 frozen and ten freshly slaughtered chicken were purchased from different selling outlets around the study area. The samples were processed using standard cultural and biochemical procedures. The results of the study showed the mean aerobic mesophilic bacterial count of 5.93 x 106 CFU/g and 3.12 x 106  CFU/g for frozen and freshly slaughtered chicken meat samples respectively. The coliform counts were 420.1 and 347.7 CFU/100g for frozen and freshly slaughtered chicken meat samples respectively. The distribution of different bacterial species revealed E. coli (26.0%), Klebsiella spp (4.0%), Salmonella spp (19.5%), Campylobacter spp. (14.6%) and Staphylococcus aureus (30%) in frozen chicken meat samples while freshly slaughtered chicken meat samples revealed E. coli (21.0%), Klebsiella spp (8.9%), Salmonella spp (30%), Campylobacter spp. (15.0%) and Staphylococcus aureus (24.0%). This showed that frozen chicken meats were more contaminated than freshly slaughtered chicken meats which might be associated with poor handling and storage conditions.

Comparison between the Vitek Immunodiagnostic Assay System and PCR for the Detection of Pathogenic Microorganisms in an Experimental Dry Sausage during Its Curing Process

2009 ◽  
Vol 72 (9) ◽  
pp. 1977-1981 ◽  
Author(s):  
R. PRIEGO ◽  
L. M. MEDINA ◽  
R. JORDANO
Keyword(s):  
Salmonella Typhimurium ◽  
Assay System ◽  
Pathogenic Microorganisms ◽  
Curing Conditions ◽  
E Coli ◽  
Pcr Method ◽  
Time Required ◽  
And Staphylococcus Aureus ◽  
Control Batch ◽  
Dry Sausage

The comparison between the Vitek Immunodiagnostic Assay System (VIDAS) and PCR methods for the detection of the pathogenic microorganisms Salmonella Typhimurium, Listeria monocytogenes, Escherichia coli O157:H7, Clostridium perfringens, and Staphylococcus aureus in salchichón (a type of Spanish fermented dry sausage) was studied. The automated mini-VIDAS method and the PCR method were used to detect the presence of these microorganisms in 90 samples grouped into six batches (one control batch, and five batches inoculated with Salmonella Typhimurium, L. monocytogenes, E. coli O157:H7, S. aureus, and C. perfringens, respectively). The determinations were carried out on fresh sausage, semicured (14 days), and finished product (28 days of curing). The concordance between both methods was 100%. For salchichón-type sausage samples, both the VIDAS method and PCR (in comparison to traditional methods) permit a significant reduction in the time required for the detection of the pathogens assayed. The absence of Salmonella Typhimurium, E. coli O157:H7, L. monocytogenes, S. aureus, their enterotoxins, and C. perfringens were verified in the control batch. Conversely, for batches inoculated with these pathogens, the results were positive in the fresh sausage up to 14 days of curing and in the finished product; this demonstrated the null or scant influence of the curing conditions and the constitutive lactic acid biota on the pathogens investigated.

Thermal Inactivation of Escherichia coli O157:H7 Isolated from Ground Beef and Bovine Feces, and Suitability of Media for Enumeration

1998 ◽  
Vol 61 (3) ◽  
pp. 285-289 ◽  
Author(s):  
M. ROCELLE S. CLAVERO ◽  
LARRY R. BEUCHAT ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Ground Beef ◽  
Treatment Temperature ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Polyethylene Bags ◽  
D Values ◽  
Bovine Feces

Rates of thermal inactivation of five strains of Escherichia coli O157:H7 isolated from ground beef implicated in outbreaks of hemorrhagic colitis and five strains isolated from bovine feces were determined. Ground beef (22% fat, 10 g), inoculated with individual test strains at populations ranging from 6.85 to 7.40 log10 CFU g−1 of beef, was formed into patties (0.3 cm thick and 8.0 cm in diameter) and sealed in polyethylene bags. For each strain and treatment temperature (54.4, 58.9, 62.8, 65.6, or 68.3°C), 6 bags were simultaneously immersed into a recirculating water bath. Viable cells in patties heated for various lengths of time were enumerated by plating diluted samples on sorbitol MacConkey agar supplemented with 4-methylumbelliferyl-β-d-glucuronide (MSMA) and modified eosin methylene blue (MEMB) agar. Regardless of strain or treatment temperature, higher numbers of E. coli O157:H7 cells were generally recovered on MEMB agar than on MSMA, indicating the inferiority of MSMA as a recovery medium for quantitative determination of E. coli O157:H7 cells in heat-processed ground beef. Significantly (P ≤ 0.05) higher D values when enumeration was done using MEMB agar compared with MSMA. Mean D values for combined strain data at 54.4, 58.9, 62.8, and 65.6°C from cultures on MEMB agar were 123.90, 6.47, 0.62, and 0.20 min, respectively, whereas D values of 25.5, 5.21, 0.57, and 0.18 min were obtained at the same temperatures from cultures on MSMA. Results suggest that cooking ground beef patties to an internal temperature of 68.3°C for 40 s will inactivate at least 99.99% of E. coli O157:H7 cells; z values of 4.0 and 5.1°C were calculated from mean D values obtained from MEMB agar and MSMA, respectively, as recovery media. Differences in D values and z values existed among strains but rates of thermal inactivation do not appear to be correlated with the sources of the isolates.

Antimicrobial Effects of Alginate-Based Film Containing Essential Oils for the Preservation of Whole Beef Muscle

2006 ◽  
Vol 69 (10) ◽  
pp. 2364-2369 ◽  
Author(s):  
MOUNIA OUSSALAH ◽  
STÉPHANE CAILLET ◽  
STÉPHANE SALMIÉRI ◽  
LINDA SAUCIER ◽  
MONIQUE LACROIX
Keyword(s):  
Essential Oils ◽  
Salmonella Typhimurium ◽  
Storage Period ◽  
Edible Films ◽  
Total Phenolic ◽  
Microbiological Analysis ◽  
Active Compounds ◽  
E Coli ◽  
Beef Muscle

Alginate-based edible films containing 1% (wt/vol) essential oils of Spanish oregano, Chinese cinnamon, or savory were immersed in 2% (wt/vol) or 20% (wt/vol) CaCl2 solution and then applied to beef muscle slices to control the growth of Escherichia coli O157:H7 and Salmonella Typhimurium. Whole beef muscle surfaces were inoculated with one of these strains at 103 CFU/cm2. During the 5 days of storage, samples of meat were obtained periodically for microbiological analysis. The availability of active compounds from essential oils present in films was evaluated by determination of total phenolic compounds for oregano- and savory-based films and of total aldehydes for cinnamon-based films during storage. After 5 days of storage, films containing oregano or cinnamon essential oils were the most effective against Salmonella Typhimurium regardless of the type of pretreatment used (2 or 20% CaCl2). During the same period, meat inoculated with E. coli O157:H7 and coated with films treated with 2% CaCl2 had significantly fewer bacteria (P ≤ 0.05) when oregano-based films were used than when cinnamon- and savory-based films were used. The E. coli O157:H7 concentration was higher at the end of the storage period when films were pretreated with 20% CaCl2. Evaluation of the active compounds in films revealed that availability in oregano-and savory-based films was significantly more important (P ≤ 0.05) than that in cinnamon-based films regardless of the type of pretreatment used (2 or 20% CaCl2). At the end of storage, release rates of 40, 60, and 77% were noted in oregano-, savory-, and cinnamon-based films in 2% CaCl2 and rates of 65, 62, and 90% were noted in the same films in 20% CaCl2.

Growth and Survival of Foodborne Pathogens in Beer

2011 ◽  
Vol 74 (10) ◽  
pp. 1670-1675 ◽  
Author(s):  
GARRY MENZ ◽  
PETER ALDRED ◽  
FRANK VRIESEKOOP
Keyword(s):  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Storage Temperature ◽  
Escherichia Coli O157 ◽  
Gram Negative ◽  
Growth And Survival ◽  
E Coli ◽  
And Storage ◽  
And Staphylococcus Aureus ◽  
Storage Temperatures

This work aimed to assess the growth and survival of four foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in beer. The effects of ethanol, pH, and storage temperature were investigated for the gram-negative pathogens (E. coli O157:H7 and Salmonella Typhimurium), whereas the presence of hops ensured that the gram-positive pathogens (L. monocytogenes and S. aureus) were rapidly inactivated in alcohol-free beer. The pathogens E. coli O157:H7 and Salmonella Typhimurium could not grow in the mid-strength or full-strength beers, although they could survive for more than 30 days in the mid-strength beer when held at 4°C. These pathogens grew rapidly in the alcohol-free beer; however, growth was prevented when the pH of the alcohol-free beer was lowered from the “as received” value of 4.3 to 4.0. Pathogen survival in all beers was prolonged at lowered storage temperatures.

scholarly journals Silver Doped Magnesium Ferrite Nanoparticles: Physico-Chemical Characterization and Antibacterial Activity

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2859
Author(s):  
Erika Fantozzi ◽  
Erlinda Rama ◽  
Cinzia Calvio ◽  
Benedetta Albini ◽  
Pietro Galinetto ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Spinel Phase ◽  
Sol Gel ◽  
Antibacterial Properties ◽  
Chemical Characterization ◽  
Metallic Silver ◽  
X Ray ◽  
Gram Positive Bacteria ◽  
Physico Chemical ◽  
And Staphylococcus Aureus

Spinel phases, with unique and outstanding physical properties, are attracting a great deal of interest in many fields. In particular, MgFe2O4, a partially inverted spinel phase, could find applications in medicine thanks to the remarkable antibacterial properties attributed to the generation of reactive oxygen species. In this paper, undoped and Ag-doped MgFe2-xAgxO4 (x = 0.1 and 0.3) nanoparticles were prepared using microwave-assisted combustion and sol–gel methods. X-ray powder diffraction, with Rietveld structural refinements combined with micro-Raman spectroscopy, allowed to determine sample purity and the inversion degree of the spinel, passing from about 0.4 to 0.7 when Ag was introduced as dopant. The results are discussed in view of the antibacterial activity towards Escherichia coli and Staphylococcus aureus, representative strains of Gram-negative and Gram-positive bacteria. The sol–gel particles were more efficient towards the chosen bacteria, possibly thanks to the nanometric sizes of metallic silver, which were well distributed in the powders and in the spinel phase, with respect to microwave ones, that, however, acquired antibacterial activity after thermal treatment, probably due to the nucleation of hematite, itself displaying well-known antibacterial properties and which could synergistically act with silver and spinel.

scholarly journals SALMONELLA TYPHIMURIUM-ESCHERICHIA COLI HYBRIDS FOR THE TRYPTOPHAN REGION

Genetics ◽  
1972 ◽  
Vol 71 (4) ◽  
pp. 491-505
Author(s):  
T Mojica-A ◽  
R B Middleton
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Relative Frequency ◽  
Accurate Determination ◽  
Genetic Material ◽  
Phenotypic Stability ◽  
E Coli ◽  
Genetic Rearrangements

ABSTRACT Fifty-eight hybrids were analyzed for their phenotypic stability, presence and nature of cryptic trp alleles and by P22-mediated transduction to yield percent homologies. The hybrids fall into 5 distinguishable classes: a haploid class in which selected E. coli genes replace equivalent sites in the S. typhimurium chromosome; three merodiploid classes in which the selected E. coli genes are integrated at novel sites in the S. typhimurium chromosome—on the same transducing fragment as the female genes selected against, with or without cryptic damage to a nearby gene, or not on the same transducing fragment; and one class in which recombination has not taken place and the E. coli DNA is presumed to be an exogenote. The homology values are heterogeneous and do not permit an accurate determination of the relative frequency of incorporation of the integrated male genetic material. A further study of 20 hybrids indicates that genetic rearrangements can occur in the hybrids.

Sign in / Sign up

Export Citation Format

Share Document