Thermal inactivation of MS2 bacteriophage as a surrogate of enteric viruses in cow milk

Data for thermal inactivation of working suspension of Enterococcus faecium in model solutions were acquired and used to develop a mathematical model for thermal inactivation of the bacterium. The model is valid within the water activity range 0.97 to 0.99; pH range 6.0 to 7.6; temperature range 60°C to 65°C, and was determined for the microorganism concentration ranges of 102 per ml to 108 per ml of the model inactivation solution. An Excel procedure was developed in Visual Basic language which enables the calculation of the final concentration of the microorganism from the input data for pH, aw, logN0, temperature, and holding time of the treatment. The proposed model was verified in experiments using cow and human milks. With cow milk, the correspondence between the experimental and the predicted data is highly satisfactory. With human milk, the model predicts a smaller effect of heating than is that manifested experimentally.

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Thermal Inactivation of Human Enteric Viruses in Sewage Sludge and Virus Detection by Nitrose Cellulose-Enzyme Immunoassay

Chemical and Biological Characterization of Municipal Sludges, Sediments, Dredge Spoils, and Drilling Muds ◽

10.1520/stp26716s ◽

2008 ◽

pp. 273-273-9

Author(s):

PC Loh ◽

RS Fujioka ◽

WM Hirano

Keyword(s):

Sewage Sludge ◽

Enzyme Immunoassay ◽

Thermal Inactivation ◽

Virus Detection ◽

Enteric Viruses ◽

Human Enteric Viruses

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Thermal Inactivation of Foodborne Enteric Viruses and Their Viral Surrogates in Foods

Journal of Food Protection ◽

10.4315/0362-028x.jfp-14-487 ◽

2015 ◽

Vol 78 (8) ◽

pp. 1597-1617 ◽

Cited By ~ 30

Author(s):

HAYRIYE BOZKURT ◽

DORIS H. D'SOUZA ◽

P. MICHAEL DAVIDSON

Keyword(s):

Thermal Processing ◽

Hepatitis A ◽

Thermal Inactivation ◽

Hepatitis A Virus ◽

Enteric Viruses ◽

Industrial Applications ◽

Inactivation Kinetics ◽

Human Consumption ◽

Foodborne Viruses

Foodborne viruses, in particular human norovirus and hepatitis A virus, are the most common causes of food-associated infections and foodborne illness outbreaks around the world. Since it is currently not possible to cultivate human noroviruses and the wild-type strain of hepatitis A virus in vitro, the use of a variety of viral surrogates is essential to determine appropriate thermal processing conditions to reduce the risk associated with their contamination of food. Therefore, the objectives of this review are to (i) present pertinent characteristics of enteric foodborne viruses and their viral surrogates, (ii) discuss the viral surrogates currently used in thermal inactivation studies and their significance and value, (iii) summarize available data on thermal inactivation kinetics of enteric viruses, (iv) discuss factors affecting the efficacy of thermal treatment, (v) discuss suggested mechanisms of thermal inactivation, and (vi) provide insights on foodborne enteric viruses and viral surrogates for future studies and industrial applications. The overall goal of this review is to contribute to the development of appropriate thermal processing protocols to ensure safe food for human consumption.

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Thermal Inactivation of Enteric Viruses and Bioaccumulation of Enteric Foodborne Viruses in Live Oysters (Crassostrea virginica)

Applied and Environmental Microbiology ◽

10.1128/aem.03573-15 ◽

2016 ◽

Vol 82 (7) ◽

pp. 2086-2099 ◽

Cited By ~ 28

Author(s):

Elbashir Araud ◽

Erin DiCaprio ◽

Yuanmei Ma ◽

Fangfei Lou ◽

Yu Gao ◽

...

Keyword(s):

Heat Treatment ◽

Receptor Binding ◽

Thermal Inactivation ◽

Hepatitis A Virus ◽

Enteric Viruses ◽

Heat Stability ◽

Magnetic Bead ◽

Murine Norovirus ◽

Foodborne Viruses ◽

Porcine Gastric Mucin

ABSTRACTHuman enteric viruses are among the main causative agents of shellfish-associated outbreaks. In this study, the kinetics of viral bioaccumulation in live oysters and the heat stabilities of the predominant enteric viruses were determined both in tissue culture and in oyster tissues. A human norovirus (HuNoV) GII.4 strain, HuNoV surrogates (murine norovirus [MNV-1], Tulane virus [TV]), hepatitis A virus (HAV), and human rotavirus (RV) bioaccumulated to high titers within oyster tissues, with different patterns of bioaccumulation for the different viruses. We tested the thermal stability of each virus at 62, 72, and 80°C in culture medium. The viruses can be ranked from the most heat resistant to the least stable as follows: HAV, RV, TV, MNV-1. In addition, we found that oyster tissues provided protection to the viruses during heat treatment. To decipher the mechanism underlying viral inactivation by heat, purified TV was treated at 80°C for increasing time intervals. It was found that the integrity of the viral capsid was disrupted, whereas viral genomic RNA remained intact. Interestingly, heat treatment leading to complete loss of TV infectivity was not sufficient to completely disrupt the receptor binding activity of TV, as determined by the porcine gastric mucin–magnetic bead binding assay. Similarly, HuNoV virus-like particles (VLPs) and a HuNoV GII.4 strain retained some receptor binding ability following heat treatment. Although foodborne viruses have variable heat stability, 80°C for >6 min was sufficient to completely inactivate enteric viruses in oysters, with the exception of HAV.

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Electron Microscopic Detection and Characterization of Nonhuman Primate Enteric Viruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054145 ◽

1982 ◽

Vol 40 ◽

pp. 306-307

Author(s):

G. C. Smith ◽

R. L. Heberling ◽

S. S. Kalter

Keyword(s):

Electron Microscopy ◽

Animal Model ◽

Nonhuman Primate ◽

Clinical Condition ◽

Intestinal Tract ◽

Enteric Viruses ◽

Electron Microscopic ◽

Microscopic Detection

A number of viral agents are recognized as and suspected of causing the clinical condition “gastroenteritis.” In our attempts to establish an animal model for studies of this entity, we have been examining the nonhuman primate to ascertain what viruses may be found in the intestinal tract of “normal” animals as well as animals with diarrhea. Several virus types including coronavirus, adenovirus, herpesvirus, and picornavirus (Table I) were detected in our colony; however, rotavirus, astrovirus, and calicivirus have not yet been observed. Fecal specimens were prepared for electron microscopy by procedures reported previously.

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Mechanism of Inhibitory Action on Platelet Activation of a Phospholipase A2 Isolated from Lachesis muta (Bushmaster) Snake Venom

Thrombosis and Haemostasis ◽

10.1055/s-0038-1665414 ◽

1997 ◽

Vol 78 (05) ◽

pp. 1372-1380 ◽

Cited By ~ 56

Author(s):

André L Fuly ◽

Olga L T Machado ◽

Elias W Alves ◽

Célia R Carlinis

Keyword(s):

Platelet Aggregation ◽

Enzymatic Activity ◽

Phospholipase A2 ◽

Inhibitory Activity ◽

Thermal Inactivation ◽

Anticoagulant Activity ◽

Gel Filtration ◽

Apparent Molecular Weight ◽

Crude Venom ◽

Lachesis Muta

SummaryCrude venom from Lachesis muta exhibited procoagulant, proteolytic and phospholipase A2 activities. A phospholipase A2, denoted LM-PLA2 was purified from L. muta venom to homogeneity, through a combination of chromatographic steps involving gel-filtration on Sephacryl S-200 HR and reverse phase chromatography on a C2/C18 column. LM-PLA2 presented a single polypeptide chain with an isoelectric point at pH 4.7 and apparent molecular weight of 17 kDa. Partial aminoacid sequence indicated a high degree of homology for LM-PLA2 with other PLA2 from different sources.LM-PLA2 displayed a potent enzymatic activity as measured by indirect hemolysis of red blood cells but it was neither lethal when injected i.p. into mice nor did it present anticoagulant activity. Furthermore, LM-PLA2 displayed a moderate inhibitory activity on the aggregation of rabbit platelets induced by low levels of ADP, thrombin and arachidonate. In contrast, platelet aggregation induced by high doses of collagen was strongly inhibited by LM-PLA2 as well as ATP-release. Treatment of the protein with p-bromophenacyl bromide or 2-mercapto-ethanol, as well as thermal inactivation studies, suggested that the platelet inhibitory effect of LM-PLA2 is dependent on its enzymatic activity. Thus, the platelet inhibitory activity of LM-PLA2 was shown to be dependent on the hydrolysis of plasma phospholipids and/or lipoproteins, most probably those rich in phosphatidylcholine. Surprisingly, lyso-phosphatidylcholine released by LM-PLA2 from plasma was shown to preferentially inhibited collagen-induced platelet aggregation, in contrast to other PLA2s, whose plasma hydrolytic products indistinctly affect platelet’s response to several agonists.

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