scholarly journals Comportamento de micro-organismos patogênicos durante processo de compostagem de carcaças de suínos

2022 ◽  
Vol 11 (1) ◽  
pp. e21011124774
Author(s):  
Aline Viancelli ◽  
Valdir Silveira de Avila ◽  
Sabrina Castilho Duarte ◽  
Everton L Krabbe ◽  
Suzana Satomi Kuchiishi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Senftenberg

O processo de compostagem é uma prática importante para aceleração da decomposição de carcaças e inativação de patógenos potencialmente presentes no material a ser decomposto. No entanto, é necessário avaliar e promover o funcionamento adequado do processo. Diante disso, o presente estudo teve por objetivo avaliar a eliminação de micro-organismos patogênicos em composteiras construídas em escala laboratorial para decomposição de carcaças de suíno trituradas e em escala piloto para decomposição de carcaças de suíno em pedaços (picadas). Para isso, foram construídas composteiras em escala laboratorial e piloto, onde foram compostadas carcaças de suínos intercaladas com camadas de maravalha, umedecidas com água. A essas composteiras foram adicionadas concentrações conhecidas de micro-organismos patogênicos modelo (Escherichia coli e Salmonella Senftenberg). A redução destes micro-organismos foi acompanhada até a não detecção dos mesmos viáveis. Os resultados indicaram que as composteiras em escala piloto, devido às suas dimensões, atingiram as condições ideais de processo e eliminaram de forma eficiente e mais rápida os patógenos (até 7 dias, quando a temperatura atingida foi acima de 60ºC). Desta forma, este processo é uma alternativa promissora para a destinação de carcaças de suínos se executado dentro de condições adequadas.

Thermal Inactivation of Escherichia coli O157: H7, Salmonella senftenberg, and Enzymes with Potential as Time-Temperature Indicators in Ground Beef

1997 ◽  
Vol 60 (5) ◽  
pp. 471-475 ◽  
Author(s):  
ALICIA ORTA-RAMIREZ ◽  
JAMES F. PRICE ◽  
YIH-CHIH HSU ◽  
GIRIDARAN J. VEERAMUTHU ◽  
JAMIE S. CHERRY-MERRITT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Triose Phosphate ◽  
Beef Products ◽  
Z Value ◽  
D Values ◽  
Salmonella Senftenberg

The USDA has established processing schedules for beef products based on the destruction of pathogens. Several enzymes have been suggested as potential indicators of heat processing. However, no relationship between the inactivation rates of these enzymes and those of pathogenic microorganisms has been determined. Our objective was to compare the thermal inactivation of Escherichia coli O157:H7 and Salmonella senftenberg to those of endogenous muscle proteins. Inoculated and noninoculated ground beef samples were heated at four temperatures for predetermined intervals of time in thermal-death-time studies. Bacterial counts were determined and enzymes were assayed for residual activity. The D values for E. coli O157:H7 were 46.10, 6.44, 0.43, and 0.12 min at 53, 58, 63, and 68°C, respectively, with a z value of 5.60°C. The D values for S. senftenberg were 53.00, 15.17, 2.08, and 0.22 min at 53, 58, 63, and 68°C, respectively, with a z value of 6.24°C. Apparent D values at 53, 58, 63, and 68°C were 352.93, 26.31, 5.56, and 3.33 min for acid phosphatase; 6968.64, 543.48, 19.61, and 1.40 min for lactate dehydrogenase; and 3870.97, 2678.59, 769.23, and 42.92 min for peroxidase; with z values of 7.41,3.99, and 7.80°C, respectively. Apparent D values at 53, 58, 63, and 66°C were 325.03, 60.07, 3.07, and 1.34 min for phosphoglycerate mutase; 606.72, 89.86, 4.40, and 1.28 min for glyceraldehyde-3-phosphate dehydrogenase; and 153.06, 20.13, 2.25, and 0.74 min for triose phosphate isomerase; with z values of 5.18, 4.71, and 5.56°C, respectively. The temperature dependence of triose phosphate isomerase was similar to those of both E. coli O157 :H7 and S. senftenberg, suggesting that this enzyme could be used as an endogenous time-temperature indicator in beef products.

Thermal inactivation of Escherichia coli O157:H7, Salmonella senftenberg, and Enzymes with Potential as Time-Temperature Indicators in Ground Turkey Thigh Meat

1998 ◽  
Vol 61 (2) ◽  
pp. 171-175 ◽  
Author(s):  
GIRIDARAN J. VEERAMUTHU ◽  
JAMES F. PRICE ◽  
CARL E. DAVIS ◽  
ALDEN M. BOOREN ◽  
DENISE M. SMITH
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Heat Processing ◽  
Performance Standard ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
Phenol Red ◽  
E Coli ◽  
Death Time ◽  
Salmonella Senftenberg

The USDA Food Safety and Inspection Service has proposed to amend cooking regulations to require that any thermal process used for poultry products be sufficient to cause a 7 D reduction in salmonellae. Several enzymes have been suggested as potential indicators of heat processing in poultry, yet no relationship between the inactivation rates of these enzymes and salmonellae has been determined. The thermal inactivation kinetics of endogenous muscle proteins, Escherichia coli O157:H7 and Salmonella senftenberg were compared in ground turkey thigh meat in thermal death time studies. Bacteria counts were determined and muscle extracts were assayed for residual enzyme activity or protein concentration. D and z values were calculated using regression analysis. S. senftenberg had higher D values at all temperatures and was more heat resistant than E. coli. The z values of E. coli on Petrifilm Coliform Count plates and phenol red sorbitol agar plates were 6.0 and 5.7°C, respectively. The z values of S. senftenberg were 5.6 and 5.4°C on Petrifilm and agar, respectively. Lactate dehydrogenase (LDH) was the most heat stable protein at 64°C. LDH, glyceraldehyde-3-phosphate dehydrogenase, creatine kinase, triose phosphate isomerase (TPI), acid phosphatase, serum albumin, and immunoglobulin G had z values of 3.8, 4.3, 4.8, 5.8, 6.3, 6.7, and 8.6°C, respectively, in turkey containing 4.3% fat. The z values for TPI decreased to 5.4°C in thigh meat containing 9.8% fat. Temperature dependence of TPI was most similar to that of S. senftenberg, suggesting it might function as an endogenous time-temperature integrator to monitor adequacy of processing when a performance standard based on this pathogen is implemented.

Salt extends the upper temperature limit for growth of food-poisoning bacteria

1981 ◽  
Vol 27 (9) ◽  
pp. 970-972 ◽  
Author(s):  
S. Tesone ◽  
A. Hughes ◽  
A. Hurst
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Protective Effect ◽  
Salt Concentration ◽  
Food Poisoning ◽  
Temperature Limit ◽  
Clostridium Sporogenes ◽  
Gram Negative ◽  
Gram Negative Organisms ◽  
Salmonella Senftenberg

Inclusion of NaCl into the growth medium raised the upper temperature limit of growth of the following organisms: Staphylococcus aureus (two strains), Salmonella senftenberg, S. typhimurium, Escherichia coli, Streptococcus faecalis, Bacillus cereus, Clostridium sporogenes, C. perfringens (two strains). The magnitude of the response varied with the culture, the largest being 3.5 °with B. cereus cells. The spores of B. cereus were not protected by salt but clostridial spores behaved as the vegetative cells (response of 2.5°). The optimal salt concentration for the protective effect varied with the organism ranging from 0.2 M for the Gram-negative organisms to 1.0 M for S. aureus.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

Infection of Escherichia coli with bacteriophages

1969 ◽  
Vol 27 ◽  
pp. 370-371
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
Cell Surface ◽  
Virus Type ◽  
Infection Process ◽  
Adsorption Site ◽  
The Other ◽  
Specific Receptors ◽  
Bacterial Receptors

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.

The Nature of the Intramembrane Particle

1980 ◽  
Vol 38 ◽  
pp. 688-691
Author(s):  
A.J. Verkleij
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Gap Junction ◽  
The Other ◽  
Fracture Face ◽  
Band 3 Protein ◽  
Satisfactory Explanation ◽  
Freeze Fracturing ◽  
Intramembrane Particle ◽  
Luminal Membrane

Freeze-fracturing splits membranes into two helves, thus allowing an examination of the membrane interior. The 5-10 rm particles visible on both monolayers are widely assumed to be proteinaceous in nature. Most membranes do not reveal impressions complementary to particles on the opposite fracture face, if the membranes are fractured under conditions without etching. Even if it is considered that shadowing, contamination or fracturing itself might obscure complementary pits', there is no satisfactory explanation why under similar physical circimstances matching halves of other membranes can be visualized. A prominent example of uncomplementarity is found in the erythrocyte manbrane. It is wall established that band 3 protein and possibly glycophorin represents these nonccmplanentary particles. On the other hand a number of membrane types show pits opposite the particles. Scme well known examples are the ";gap junction',"; tight junction, the luminal membrane of the bladder epithelial cells and the outer membrane of Escherichia coli.

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