scholarly journals Microbiological studies on hamburgers

1982 ◽  
Vol 88 (1) ◽  
pp. 125-142 ◽  
Author(s):  
S. K. Tamminga ◽  
R. R. Beumer ◽  
E. H. Kampelmacher
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Yersinia Enterocolitica ◽  
Most Probable Number ◽  
Probable Number ◽  
Bacterial Counts ◽  
Microbiological Examination ◽  
D Values ◽  
Group D

SummaryOne hundred and eighty-two raw, 112 pre-cooked and 750 cooked hamburgers composed mainly of beef or beef and pork were subjected to microbiological examination.Raw hamburgers gave total bacterial counts from 105to 108per g, counts of Enterobacteriaceae from 104to 108per g, ofEscherichia colifrom 103to 105, of group D streptococci from 102to 104, ofStaphylococcus aureusfrom 3 to 102and ofClostridium perfringensless than 10 bacteria per g. Of the samples, 32 % contained salmonellas; the highest most probable number was 102per g but most estimates were below 1 per g. Corresponding figures for the pre-cooked samples were 2–3 log cycles lower, and only one sample contained salmonella.Yersinia enterocoliticawas not isolated from any raw or pre-cooked sample.Three hundred and ninety-five of the cooked hamburgers were prepared by grilling raw hamburgers for between 2 and 5·5 min. These gave total bacterial counts from 105to 107per g, and counts of Enterobacteriaceae from 102to 105per g. Of the samples, 9·4 % contained salmonellas, always in numbers below 1 per g. The remaining 355 cooked hamburgers were prepared from samples pre-cooked for 10 min at 80 °C. Some were grilled and some fat fried. The total bacterial counts were from 103to 105per g, and counts of Enterobacteriaceae below 102perg. Salmonellae, again in small numbers only, were recovered from 3·5 % of samples.When hamburgers were artificially contaminated withSalmonella typhimuriumit took 5·5 min on a commercial grill, 2·25 min frying in a frying pan and 1·75 min on a household grill to reliably reduce the salmonella count one hundredfold. This means that at many vending places hamburgers are often cooked for too short a time.D-values were determined forS. typhimuriumin hamburger meat at 50, 55, 60, 65 and 70 °C, these values were 7·1, 5·1, 1·2, 0·9 and 0·6 min respectively. It can be concluded that the heating action in the centre of the hamburgers will take place more slowly than in the hamburger as a whole, and that the time between cooking and consumption is very important in reducing the microbial load to acceptable levels.Pre-cooking (10 min at 80 °C in a water bath) gives a reduction in the numbers of salmonella of about 4 × 103, after which cooking gives a further reduction as mentioned above.

scholarly journals Gamma irradiation in the control of pathogenic bacteria in refrigerated ground chicken meat

2000 ◽  
Vol 57 (3) ◽  
pp. 389-394 ◽  
Author(s):  
Marta Helena Filet Spoto ◽  
Cláudio Rosa Gallo ◽  
André Ricardo Alcarde ◽  
Maria Sílvia do Amaral Gurgel ◽  
Lucimara Blumer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Radiation Dose ◽  
Gamma Radiation ◽  
Salmonella Typhimurium ◽  
Gamma Irradiation ◽  
Pathogenic Bacteria ◽  
Chicken Meat ◽  
Chicken Breast ◽  
D Values

This work evaluated the effect of gamma radiation on reducting the population of Staphylococcus aureus, Escherichia coli and Salmonella typhimurium in ground chicken breast stored under refrigeration. The experiment included a control and 4 doses of gamma radiation (2.0, 4.0, 6.0 and 8.0 kGy) along with 5 periods of storage under refrigeration (1, 7, 14, 21 and 28 days). Samples of ground chicken breast were inoculated with Staphylococcus aureus (ATCC 14458), Escherichia coli (ATCC 11105) and Salmonella typhimurium (ATCC 0626), irradiated at temperatures between 4 and 8°C and stored under refrigeration (5°C) for 28 days. The increased radiation dose and period of storage under refrigeration caused a reduction of Staphylococcus aureus, Escherichia coli and Salmonella typhimurium populations in the ground chicken breast. Mean radiation D values determined for Staphylococcus aureus and Escherichia coli were 0.41 and 0.72 kGy, respectively. Gamma irradiation was an effective treatment for chicken meat conservation because the radiation dose of 6.0 kGy kept the ground chicken breast within the microbiological limits established by the Brazilian legislation, for up to 28 days under refrigeration.

Inhibition and Inactivation of Five Species of Foodborne Pathogens by Chitosan

1992 ◽  
Vol 55 (11) ◽  
pp. 916-919 ◽  
Author(s):  
GUANG-HUA WANG
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Acetic Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Yersinia Enterocolitica ◽  
Foodborne Pathogens ◽  
E Coli ◽  
No Inhibition

Inhibition and inactivation of five species of foodborne pathogens (Staphylococcus aureus, Escherichia coli, Yersinia enterocolitica, Listeria monocytogenes, and Salmonella typhimurium) by chitosan were studied. Nutrient broths were supplemented with 0, 0.5, 1.0, 1.5, 2.0, and 2.5% chitosan, adjusted to pH 6.5 or 5.5 with 2% acetic acid, and incubated at 30°C. The outgrowths of these bacteria were observed. At pH 6.5, in general, antibacterial activity of chitosan was relatively weak. The effectiveness of chitosan against S. aureus was greatest, followed by S. typhimurium, E. coli, and Y. enterocolitica. As the concentration of chitosan increased, the effectiveness of chitosan against these four species of pathogens also increased. No inhibition of L. monocytogenes by chitosan occurred. At pH 5.5, presence of chitosan inactivated these pathogens except that 0.5% chitosan did not affect the growth of S. typhimurium. Thus, the antibacterial activity of chitosan was stronger at pH 5.5 than at pH 6.5.

Bactericidal Effect of Sodium Chlorate on Escherichia coli O157:H7 and Salmonella Typhimurium DT104 in Rumen Contents In Vitro

2000 ◽  
Vol 63 (8) ◽  
pp. 1038-1042 ◽  
Author(s):  
ROBIN C. ANDERSON ◽  
SANDRA A. BUCKLEY ◽  
LEON F. KUBENA ◽  
LARRY H. STANKER ◽  
ROGER B. HARVEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Salmonella Typhimurium ◽  
Bactericidal Effect ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Respiratory Nitrate Reductase

Escherichia coli O157:H7 and Salmonella Typhimurium DT104 are important foodborne pathogens affecting the beef and dairy industries and strategies are sought to rid these organisms from cattle at slaughter. Both pathogens possess respiratory nitrate reductase that also reduces chlorate to the lethal chlorite ion. Because most anaerobes lack respiratory nitrate reductase, we hypothesized that chlorate may selectively kill E. coli O157:H7 and Salmonella Typhimurium DT104 but not potentially beneficial anaerobes. In support of this hypothesis, we found that concentrations of E. coli O157:H7 and Salmonella Typhimurium DT104 were reduced from approximately 1,000,000 colony forming units (CFU) to below our level of detection (≤10 CFU) following in vitro incubation (24 h) in buffered ruminal contents (pH 6.8) containing 5 mM added chlorate. In contrast, chlorate had little effect on the most probable number (mean ± SD) of total culturable anaerobes (ranging from 9.9 ± 0.72 to 10.7 ± 0.01 log10 cells/ml). Thus, chlorate was bactericidal to E. coli O157:H7 and Salmonella Typhimurium DT104 but not to potentially beneficial bacteria. The bactericidal effect of chlorate was concentration dependent (less at 1.25 mM) and markedly affected by pH (more bactericidal at pH 6.8 than pH 5.6).

scholarly journals Identification of Bacteria, Fungi, and Most Probable Coliform around Temporary Disposal Site at Gadang Village Banjarmasin

2020 ◽  
Vol 16 (2) ◽  
pp. 89
Author(s):  
Farida Heriyani ◽  
Lia Yulia Budiarti ◽  
Nurlaili Rafina ◽  
Normaida Novianti ◽  
Puspa Astri Sella
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Aspergillus Niger ◽  
Coliform Bacteria ◽  
Disposal Site ◽  
Most Probable Number ◽  
Risk Category ◽  
Probable Number ◽  
Piped Water ◽  
Air Contaminant

Abstract: Temporary Disposal Site (TDS) of Gadang Village Banjarmasin is one of the temporary landfills in Banjarmasin. The negative effects of waste can pollute the environment, including water and air. The purpose of this study was to identify airborne contaminant bacteria and fungi as well as the Most Probable Number (MPN) of Coliform value of piped water in the residential houses around Gadang TDS Banjarmasin. The research method is descriptive observational. The sample of this study were air and piped water. Air sampling is done by open plate and MPN Coliform sampling was obtained by purposive sampling method. The results of this study showed the air contaminant bacteria in the house were Staphylococcus aureus (55.56%) and Escherichia coli (44.44%) in the environment around the TDS all results were obtained with the same percentage. Aspergillus niger was dominantly found at a distance of 20-30 m and 40-50 m while Aspergillus flavus was mostly found at the distance around 30-40 m. MPN Coliform in piped water showed coliform bacteria contamination with MPN coliform index of 2.0-7.5/100ml water samples. In conclusion, Staphylococcus aureus bacteria is more common than Escherichia coli. Most fungi species found in this study was Aspergillus niger. In the piped water examination for all samples MPN Coliform was found in the low risk category. Keywords: Air contaminant bacteria, air contaminant fungi, piping water MPC coliform, Temporary Disposal Site

scholarly journals Analisis Cemaran Escherichia coli, Salmonella sp., Staphylococcus aureus, dan Bacillus cereus pada Minuman Susu Kedelai di Kota Padang

2019 ◽  
Vol 11 (02) ◽  
pp. 1
Author(s):  
Sari Mustika ◽  
Ranggi Rahimul Insan ◽  
Anni Faridah
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Bacillus Cereus ◽  
Most Probable Number ◽  
Probable Number

Minuman susu kedelai dibuat dengan bahan dasar kedelai digiling halus, ditambahkan air dan disaring, yang kemudian menghasilkan cairan berwarna putih seperti susu. Apabila pada proses pembuatannya tidak baik dan bersih, maka dapat terkontaminasi oleh beberapa bakteri pathogen seperti; bakteri Escherichia Coli, Salmonella sp. sp., Staphylococcus aureus, dan Bacillus cereus yang dapat menyebabkan timbulnya berbagai penyakit pada orang yang mengkonsumsi. Penelitian ini merupakan penelitian deskriptif dengan metode pendekatan kualitatif, bertujuan untuk menganalisis dan mengetahui adanya cemaran bakteri patogen Escherichia Coli, Salmonella sp, Staphylococcus aureus, dan Bacillus cereus yang terdapat pada minuman jajanan susu kedelai di Kota Padang. Penelitian ini menggunakan sampel sebanyak 9 buah yang terdiri dari minuman susu kedelai yang didapat dari pasar tradisional di Kota Padang. Jumlah bakteri pada masing-masing sampel dihitung menggunakan metode Most Probable Number (MPN). Hasil penelitian diperoleh dari 9 sampel yang diuji sebagian besar sampel positif tercemar bakteri patogen dan jumlahnya melebihi dari batas yang sesuai yang syaratkan SNI 7388-2009 tentang syarat mutu minuman susu kedelai.

scholarly journals Autophagy—A Story of Bacteria Interfering with the Host Cell Degradation Machinery

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 110
Author(s):  
Anna K. Riebisch ◽  
Sabrina Mühlen ◽  
Yan Yan Beer ◽  
Ingo Schmitz
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Immune Response ◽  
Mycobacterium Tuberculosis ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Innate Immune ◽  
Intracellular Pathogens ◽  
Response Mechanism ◽  
Pathogenic Escherichia Coli

Autophagy is a highly conserved and fundamental cellular process to maintain cellular homeostasis through recycling of defective organelles or proteins. In a response to intracellular pathogens, autophagy further acts as an innate immune response mechanism to eliminate pathogens. This review will discuss recent findings on autophagy as a reaction to intracellular pathogens, such as Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Staphylococcus aureus, and pathogenic Escherichia coli. Interestingly, while some of these bacteria have developed methods to use autophagy for their own benefit within the cell, others have developed fascinating mechanisms to evade recognition, to subvert the autophagic pathway, or to escape from autophagy.

scholarly journals Lessons from a large outbreak of Escherichia coli O157[ratio ]H7 infections: insights into the infectious dose and method of widespread contamination of hamburger patties

1999 ◽  
Vol 122 (2) ◽  
pp. 185-192 ◽  
Author(s):  
J. TUTTLE ◽  
T. GOMEZ ◽  
M. P. DOYLE ◽  
J. G. WELLS ◽  
T. ZHAO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Most Probable Number ◽  
Strong Argument ◽  
Probable Number ◽  
Infectious Dose ◽  
E Coli ◽  
Beef Patties ◽  
Large Outbreak ◽  
Microbiological Testing

Between November 1992 and February 1993, a large outbreak of Escherichia coli O157[ratio ]H7 infections occurred in the western USA and was associated with eating ground beef patties at restaurants of one fast-food chain. Restaurants that were epidemiologically linked with cases served patties produced on two consecutive dates; cultures of recalled ground beef patties produced on those dates yielded E. coli O157[ratio ]H7 strains indistinguishable from those isolated from patients, confirming the vehicle of illness. Seventy-six ground beef patty samples were cultured quantitatively for E. coli O157[ratio ]H7. The median most probable number of organisms was 1·5 per gram (range, <0·3–15) or 67·5 organisms per patty (range, <13·5–675). Correlation of the presence of E. coli O157[ratio ]H7 with other bacterial indicators yielded a significant association between coliform count and the presence of E. coli O157[ratio ]H7 (P=0·04). A meat traceback to investigate possible sources of contamination revealed cattle were probably initially colonized with E. coli O157[ratio ]H7, and that their slaughter caused surface contamination of meat, which once combined with meat from other sources, resulted in a large number of contaminated ground beef patties. Microbiological testing of meat from lots consumed by persons who became ill was suggestive of an infectious dose for E. coli O157[ratio ]H7 of fewer than 700 organisms. These findings present a strong argument for enforcing zero tolerance for this organism in processed food and for markedly decreasing contamination of raw ground beef. Process controls that incorporate microbiological testing of meat may assist these efforts.

scholarly journals ATIVIDADE ANTIMICROBIANA DE MICRORGANISMOS ISOLADOS DE GRÃOS DE KEFIR

2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Priscila Alves Dias ◽  
Daiani Teixeira Silva ◽  
Cláudio Dias Timm
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Salmonella Enterica ◽  
Escherichia Coli O157 ◽  
E Coli

Resumo Kefir é o produto da fermentação do leite pelos grãos de kefir. Esses grãos contêm uma mistura simbiótica de bactérias e leveduras imersas em uma matriz composta de polissacarídeos e proteínas. Muitos benefícios à saúde humana têm sido atribuídos ao kefir, incluindo atividade antimicrobiana contra bactérias Gram positivas e Gram negativas. A atividade antimicrobiana de 60 microrganismos isolados de grãos de kefir, frente à Escherichia coli O157:H7, Salmonella enterica subsp. enterica sorotipos Typhimurium e Enteritidis, Staphylococcus aureus e Listeria monocytogenes, foi estudada através do teste do antagonismo. A ação antimicrobiana dos sobrenadantes das bactérias ácido-lácticas que apresentaram atividade no teste do antagonismo foi testada. O experimento foi repetido usando sobrenadantes com pH neutralizado. Salmonella Typhimurium e Enteritidis sobreviveram por 24 horas no kefir em fermentação. E. coli O157:H7, S. aureus e L. monocytogenes foram recuperados até 72 horas após o início da fermentação. Todos os isolados apresentaram atividade antimicrobiana contra pelo menos um dos patógenos usados no teste do antagonismo. Sobrenadantes de 25 isolados apresentaram atividade inibitória e três mantiveram essa atividade com pH neutralizado. As bactérias patogênicas estudadas sobreviveram por tempo superior àquele normalmente utilizado para a fermentação do kefir artesanal, o que caracteriza perigo em potencial para o consumidor quando a matéria-prima não apresentar segurança sanitária. Lactobacillus isolados de grãos de kefir apresentam atividade antimicrobiana contra cepas de E. coli O157:H7, Salmonella sorotipos Typhimurium e Enteritidis, S. aureus e L. monocytogenes além daquela exercida pela diminuição do pH.

scholarly journals Mechanically Ventilated Broiler Sheds: a Possible Source of Aerosolized Salmonella, Campylobacter, and Escherichia coli

2009 ◽  
Vol 75 (23) ◽  
pp. 7417-7425 ◽  
Author(s):  
H. N. Chinivasagam ◽  
T. Tran ◽  
L. Maddock ◽  
A. Gale ◽  
P. J. Blackall
Keyword(s):  
Escherichia Coli ◽  
Most Probable Number ◽  
Production Cycle ◽  
Airborne Bacteria ◽  
Probable Number ◽  
Mechanically Ventilated ◽  
The Public ◽  
E Coli ◽  
Poultry Farms ◽  
Low Levels

ABSTRACT This study assessed the levels of two key pathogens, Salmonella and Campylobacter, along with the indicator organism Escherichia coli in aerosols within and outside poultry sheds. The study ranged over a 3-year period on four poultry farms and consisted of six trials across the boiler production cycle of around 55 days. Weekly testing of litter and aerosols was carried out through the cycle. A key point that emerged is that the levels of airborne bacteria are linked to the levels of these bacteria in litter. This hypothesis was demonstrated by E. coli. The typical levels of E. coli in litter were ∼108 CFU g−1 and, as a consequence, were in the range of 102 to 104 CFU m−3 in aerosols, both inside and outside the shed. The external levels were always lower than the internal levels. Salmonella was only present intermittently in litter and at lower levels (103 to 105 most probable number [MPN] g−1) and consequently present only intermittently and at low levels in air inside (range of 0.65 to 4.4 MPN m−3) and once outside (2.3 MPN m−3). The Salmonella serovars isolated in litter were generally also isolated from aerosols and dust, with the Salmonella serovars Chester and Sofia being the dominant serovars across these interfaces. Campylobacter was detected late in the production cycle, in litter at levels of around 107 MPN g−1. Campylobacter was detected only once inside the shed and then at low levels of 2.2 MPN m−3. Thus, the public health risk from these organisms in poultry environments via the aerosol pathway is minimal.

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