Flocculants for Recovery of Food-Borne Viruses

Kostenbader, K. D.; Cliver, Dean O.

doi:10.1128/aem.41.1.318-320.1981

Cited by 19 publications

(6 citation statements)

References 7 publications

(5 reference statements)

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“…1.7 ml/75-cm2 flask) was shown to produce a greater number of PFU than inoculation of monolayers with greater volumes (21). The 2.5-ml inocula used in these studies are a compromise between those investigators who used less (7, 17, 24-26, 31) and those who used more (15,18,28) per 75-cm2 monolayer.…”

Section: Resultsmentioning

confidence: 99%

Influence of adsorption time, rocking, and soluble proteins on the plaque assay of monodispersed poliovirus

Richards¹,

Weinheimer²

1985

Appl Environ Microbiol

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Factors that could affect adsorption of monodispersed poliovirus to cell culture monolayers were evaluated. These included varying the virus adsorption period under static and nonstatic (rocked) conditions and altering the rocking rate. The effects of several soluble proteins on plaque formation, enumeration, and size were also evaluated. Rocking involved the mechanical spread of viruses over cell culture monolayers for 1 to 4 h. Rocked cultures exhibited significantly higher (P less than 0.05) plaque counts than corresponding static cultures. Optimal plaque counts were obtained after a 2-h adsorption period with rocking; increasing the period to 4 h did not significantly increase PFU. Optimal counts were not obtained until greater than or equal to 4 h with static adsorption. Plaque counts were not affected by increasing the rocking rate above one oscillation per minute, but a slower rocking rate resulted in a significant decrease in plaques. Adsorption of poliovirus in the presence of 3% solutions of beef and meat extracts, acid-precipitated oyster protein, two brands of skim milk, and 3 and 10% fetal bovine serum was compared with adsorption in protein-free controls. Significant reductions (P less than 0.05) in plaque counts occurred with one brand of skim milk, whereas 3% beef extract yielded highly significant reductions (P less than 0.01) in plaque counts and appreciable decreases in plaque sizes. Salinities of protein-containing virus inocula were high for beef and meat extracts but somewhat below physiological levels for the remaining inocula. Beef extract-associated reductions in PFU were eliminated after the extracts were dialyzed. Plaque reductions were associated with dialyzable components of the beef extract but not with the inoculum salinity.

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Section: Resultsmentioning

confidence: 99%

Influence of adsorption time, rocking, and soluble proteins on the plaque assay of monodispersed poliovirus

Richards¹,

Weinheimer²

1985

Appl Environ Microbiol

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“…The resulting concentrate was adjusted to pH 7.2, treated with antibiotics, and assayed for virus. The relative efficiency of this procedure was obtained by comparing virus recoveries with those of several existing procedures (9,13,19). The procedure routinely recovered a significantly greater number of viruses (data not shown).…”

Section: Methodsmentioning

confidence: 99%

Inefficient accumulation of low levels of monodispersed and feces-associated poliovirus in oysters

Landry¹,

Vaughn²,

Vicale³

et al. 1982

Appl Environ Microbiol

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The accumulation of low levels (0.002 to 0.18 PFU/ml) of both feces-associated and monodispersed poliovirus by oysters (Crassostrea virginica or C. gigas) and clams (Mercenaria mercenaria) was investigated. These levels were chosen to duplicate the conditions present in light to moderately polluted waters. Experiments were performed in both small-and large-scale flowing seawater systems, developed to mimic the natural marine habitats of shellfish. Under these experimental conditions, viral accumulation by physiologically active shellfish was only noted when water column concentrations exceeded approximately 0.01 PFU/ml. Bioaccumulation increased with increasing concentrations of both monodispersed and feces-associated viruses. At virus concentrations below this level, viruses were seldom detected in either clams or oysters. Evidence indicated that the lack of accumulation was not the result of inefficient extraction or detection methods. The modified Cat-Floc-beef extract procedure used in the experiment was found to be capable of detecting as few as 1.5 to 2.0 PFU per shellfish. Evidence is presented to indicate that an uptake-depuration equilibrium was present at virus exposure levels of 0.10 PFU/ml, but not at 0.01 PFU/ml. The results suggested that viral accumulation by shellfish may not be efficient at water column concentrations below-0.01 PFU/ml.

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“…With this and limited support from other sources, we planned to produce the viruses in Madison and send them to Lowell to be inoculated into the shellfish and irradiated as was done in the earlier study, with the soft tissue shipped back frozen for assay in our laboratory. Extraction of the virus was to be done by our ''Cat-Floc'' method (Kostenbader and Cliver 1981). Because of the high cost of irradiation, we mixed poliovirus 1 (PO1) with HAV, so that they could be inoculated and irradiated together.…”

Section: Irradiationmentioning

confidence: 99%

“…Filtrates could be filter-sterilized (0.20 lm porosity) and concentrated before testing in cell culture; recoveries of at least 80% were recorded with optimal selection of procedures. In a later version, the Whatman GF/F glass fiber filter was substituted and a great number (seven dry-form and 13 liquid) of polyelectrolytes were compared for recovery of PO1 from ground beef (Kostenbader and Cliver 1981). Cat-Floc T performed best among the liquids (88% recovery), and Cation 105C (ICI America, Wilmington, Del.)…”

Section: Food Matrixmentioning

confidence: 99%

Early Days of Food and Environmental Virology

Cliver

2010

Food Environ Virol

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In July 1962, the author joined the Food Research Institute (FRI), then at the University of Chicago, to become its food virologist. There was a limited record of waterborne viral disease outbreaks at the time; recorded data on foodborne outbreaks were fewer still. Laboratory environmental (water and wastewater) virology was in its infancy, and food virology was in gestation. Detection of viruses was most often attempted by inoculation of primary primate cell cultures, with observation for plaque formation or cytopathic effects. Focus was initially on enteroviruses and reoviruses. Environmental and food samples had to be liquefied if not already in liquid form; clarified to remove solids, bacteria, and fungi; and concentrated to a volume that could be tested in cell culture. Cytotoxicity was also a concern. Studies at the FRI and some other laboratories addressed all of these challenges. The FRI group was the World Health Organization’s Collaborating Center for Food Virology for many years. Other topics studied were virus inactivation as functions of temperature, time, matrix, disinfectants, and microbial action; peroral and ex-vivo infectivity; and the suitability of various virus surrogates for environmental monitoring and inactivation experiments. Detection of noroviruses and hepatitis A virus required molecular methods, most often RT-PCR. When it was found that inactivated virus often gave the same RT-PCR signal as that of infectious virus, sample treatments were sought, which would prevent false-positive test results. Many laboratories around the world have taken up food and environmental virology since 1962, with the result that a dedicated journal has been launched.

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Flocculants for Recovery of Food-Borne Viruses

Cited by 19 publications

References 7 publications

Influence of adsorption time, rocking, and soluble proteins on the plaque assay of monodispersed poliovirus

Influence of adsorption time, rocking, and soluble proteins on the plaque assay of monodispersed poliovirus

Inefficient accumulation of low levels of monodispersed and feces-associated poliovirus in oysters

Early Days of Food and Environmental Virology

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