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Biomedical subjects

G E Rodrick

Publications and source records attributed to G E Rodrick.

At least 19 recordsLinked to original sources
PubMed2006

Effects of packaging systems on the natural microflora and acceptability of chicken breast meat.

The effect of 3 packaging systems on the spoilage microflora, objective color, and sensory characteristics of fresh commercial broiler chicken breast meat was investigated. Fresh skinless and boneless chicken broiler breasts were purchased from a local poultry processing plant and packaged in either (1) a conventional Styrofoam tray with polyvinyl chloride overwrap and absorbent pad, (2) a Styrofoam tray with polyvinyl chloride overwrap minus absorbent pad, or (3) a Fresh-R-Pax (FRP) container equipped with an absorbent liner-gel system. All packages were heat sealed and stored at 1.2 +/- 1 degrees C for 8 d. At each sampling period (0, 2, 4, 6, and 8 d), packages from each treatment were analyzed for Pseudomonas spp., psychrotrophic organisms, objective color, and sensory characteristics. In general, Pseudomonas spp. and psychrotrophic counts increased as storage time increased for all packaging systems. Color and overall appearance were similar (P >0.05) for all packaging systems. Although not significant, the off-odor scores for breast meat packaged in FRP were higher (P >0.05) after 6 and 8 d when compared with the breast meat packaged in a Styrofoam tray with polyvinyl chloride overwrap with or without an absorbent pad. Although the absorbent pad did not control microbial growth, it maintained aesthetic appeal by absorbing all visible moisture released from the meat during storage.

Animals↗
PubMed2001

Populations of Vibrio parahaemolyticus in retail oysters from Florida using two methods.

Vibrio parahaemolyticus is a naturally occurring estuarine bacterium that is often associated with gastroenteritis in humans following consumption of raw molluscan shellfish. A number of studies have investigated the environmental distribution of V. parahaemolyticus, but little is known about the levels of this organism during distribution of oysters or at the point of consumption. Duplicate samples of shellstock oysters were collected monthly (September 1997 to May 1998) from the same four restaurants and three wholesale seafood markets in the Gainesville, Fla. area and analyzed for total V. parahaemolyticus densities using two methods: a standard MPN method (BAM-MPN) and a new direct plating procedure (direct-VPAP). Both methods employed an alkaline phosphatase-labeled DNA probe (VPAP) targeting the species-specific thermolabile hemolysin (tlh) gene to confirm suspect colonies as V. parahaemolyticus. The highest monthly geometric mean V. parahaemolyticus density was observed in October of 1997 (approximately 3,000/g) with similarly high values during September and November of 1997. From December 1997 to May 1998 mean densities were generally less than 100/g, falling to approximately 10/g in February and March. A strong correlation (r = 0.78) between the direct-VPAP and BAM-MPN methods for determining V. parahaemolyticus densities in market-level oysters was observed. The direct-VPAP method was more rapid and precise while the BAM-MPN was more sensitive and may better recover stressed cells. The utilization of the VPAP probe for identification of V. parahaemolyticus sharply reduced the labor for either method compared to biochemical identification techniques used in earlier V. parahaemolyticus surveys.

Animals↗
PubMed1999

Microbial, physical, and chemical quality of packaged ice in Florida.

In a statewide survey, ice samples purchased at retail were evaluated for labeling information and microbiological, chemical, and physical quality. Only 11% of bags from on-premises manual facilities, compared to 79% for off-premises mechanical facilities, had appropriate label information. One ice sample exceeded the state regulatory limit for aerobic plate count (APC) (<500 CFU/ml). Yeasts and molds were detected in 12% of the samples. No Listeria monocytogenes were found in any of the samples. Coliform counts exceeding the state regulatory limit (<1/100 ml) were observed in 13.5% of manual, on-premises facilities compared to 3.6% of samples from mechanical, off-premises facilities. No significant differences were detected between samples from on- and off-premises facilities with regard to chemical composition (e.g., aluminum, ammonium, boron, barium, calcium, cadmium, chloride, copper, iron, lead, magnesium, manganese, nickel, nitrate, phosphorus, potassium, sodium, silicon, and zinc), electrical conductivity, or pH. All samples analyzed were in compliance with appropriate Environmental Protection Agency drinking water standards. In general, all ice samples were acceptable in terms of water hardness values. Approximately 33% of samples from off-premises facilities and 62% of the on-premises samples had detectable particulate matter. None of the off-premises samples, compared to 8% of the on-premises samples, had particulate matter in the "pronounced" category.

Florida↗
PubMed1995

Effect of oxytetracycline-medicated feed on antibiotic resistance of gram-negative bacteria in catfish ponds.

The effect of oxytetracycline-medicated feeds on antibiotic resistance in gram-negative bacteria from fish intestines and water in catfish ponds was investigated. In experiments in the fall and spring, using ponds with no previous history of antibiotic usage, percentages of tetracycline-resistant bacteria in catfish intestines obtained from medicated ponds increased significantly after 10 days of treatment. In the fall, resistance of the intestinal and aquatic bacteria returned to pretreatment levels within 21 days after treatment. In the spring, resistance declined after treatment but remained higher than pretreatment levels for at least 21 days in intestinal bacteria and for 5 months in aquatic bacteria. Plesiomonas shigelloides, Aeromonas hydrophila, and Citrobacter freundii were isolated frequently in both spring and fall; Escherichia coli, Klebsiella pneumoniae, Edwardsiella tarda, and Enterobacter spp. were isolated primarily in the spring. Oxytetracycline treatment did not affect the distribution of bacterial species in the fall but may have accelerated a shift toward greater prevalence of members of the family Enterobacteriaceae in the spring. Multiple antibiotic resistance did not appear to be elicited by oxytetracycline treatment.

Animal Feed↗
PubMed1991

Ozone depuration of Vibrio vulnificus from the southern quahog clam, Mercenaria campechiensis.

Southern quahog clams, Mercenaria campechiensis, were dosed with Vibrio vulnificus and placed in a pilot-scale depuration system using ozonated recirculated artificial seawater. Twenty-four hours of treatment with ozone-treated recirculating artificial seawater reduced the numbers of V. vulnificus in the shellfish meats by an average of 2 log units when compared to natural die-off in control clams. The oxidant levels (up to 3 mg/liter) did not adversely affect shellfish pumping during the depuration process.

Animals↗
PubMed1990

Marking snails with numbered, colored discs: a technique for identifying individual specimens.

Numbered, colored discs, measuring 2.5 mm in diameter, were evaluated under laboratory conditions as tags for marking and identifying individual snails. Discs were affixed to the shells of specimens of Helisoma duryi (Pulmonata: Planorbidae) with an adhesive supplied with the discs and with waterproof epoxy. All snails survived the initial tagging procedure and showed no observable behavioral responses to the tagging. The supplied adhesive, intended for use with terrestrial insects, was inadequate for securing the tags for prolonged periods under aquatic conditions. Use of waterproof epoxy, however, resulted in 100% tag retention for over 5 months without significant mortality. The permanence of the marks, their coding of individuals, the rapidity and ease with which the tags can be applied without causing behavioral changes or snail mortality suggest that this technique will be useful in studies requiring identification of individual aquatic snails.

Adhesives↗
PubMed1987

Larval Sulcascaris sulcata from calico scallops, Argopecten gibbus, along the southeast coast of the United States.

Adductor muscles of calico scallops, Argopecten gibbus, collected off the southeastern coast of the United States from May 1982 to December 1984 were examined for the presence of larvae of the parasitic nematode, Sulcascaris sulcata. Infection intensity, prevalence, and larval length were all positively correlated (P less than 0.001) with scallop shell height (age). Prevalence was generally highest in December and lowest in August as a result of yearly trends in the age structure of the scallop population. Prevalence was not influenced by latitude or depth over the ranges examined. The rate of infection of marine molluscs by S. sulcata is generally related to the degree and length of exposure to third-stage larvae, whose distribution is essentially that of the marine turtle definitive host. Thus, over the wide geographic area of the east coast of the U.S., overall rates of infection decrease with increasing latitude.

Animals↗
PubMed1985

Vibrio vulnificus resists phagocytosis in the absence of serum opsonins.

Invasive disease caused by Vibrio vulnificus may result partially from resistance to phagocytic host defense mechanisms. The present studies show that V. vulnificus resists phagocytosis by murine peritoneal macrophages in the absence of serum opsonins and extracellular bacterial products, apparently through the anti-phagocytic properties of the bacterial surface.

Animals↗
PubMed1984

Succinate dehydrogenase in various tissues of Anodonta couperiana, Elliptio buckleyi and Mercenaria campechiensis (Mollusca: Bivalvia).

The specific activities, kinetic constants and pH optima for succinate dehydrogenase were determined in mantle, gill and adductor muscle from three bivalves (Anodonta couperiana, Elliptio buckleyi and Mercenaria campechiensis). In general the Km values for succinate and Ki values for fumarate differed in all bivalve tissues whereas the Ki for malonate was consistently low. The ratio of Ki (fumarate) to Km (succinate) was less than one for all tissues studied. This is similar to many facultative anaerobes with fumarate reductase activity.

Animals↗
PubMed1983

Marine noncholera Vibrio infections in Florida.

In the past decade, there has been a dramatic increase in the number of reported cases of clinical illness from noncholera (marine) vibrio infections, leading to a greater recognition of this potentially lethal disease. The wide spectrum of pathogenicity of this organism is reflected in the six cases in this report, varying from simple gastroenteritis to focal necrotizing cellulitis to fatal septicemia. We have reviewed the fundamental clinical differences between Vibrio vulnificus and other noncholera vibrio infections. Physicians treating patients with a history of exposure to coastal waters and/or seafood should be aware of the clinical features and the potential for significant morbidity and mortality of associated Vibrio vulnificus infections.

Adult↗
PubMed1983

Effects of storage on microbial loads of two commercially important shellfish species, Crassostrea virginica and Mercenaria campechiensis.

The effects of storage on the microbial load in two commercially important species of shellfish were examined. Oysters (Crassostrea virginica) were stored as shellstock, shucked meats, and fully processed meats at four temperatures for up to 21 days, and clams (Mercenaria campechiensis) were stored only as shellstock. The concentrations of most microbiological groups of organisms increased with the duration and temperature of storage in both shellfish species, although the increases were significantly lower in claims. Concentrations of Vibrio cholerae rose by approximately 1 log in oysters stored as shellstock after 7 days at 2 degrees C, and Lac+ vibrios increased 2 logs at 8 degrees C. Total counts of bacteria, fungi, coliforms, fecal streptococci, Aeromonas hydrophila, and clostridia were significantly higher in shucked oysters than in those stored as shellstock. Fecal coliforms were statistically the same, but V. cholerae, Vibrio parahaemolyticus, and the Lac+ vibrios were higher in oysters stored as shellstock. The concentrations of all microbial groups were higher in fully processed oysters than in shucked meats, with the exception of the vibrios, which showed no significant difference among the treatments. The results showed that although traditional methods of storing shellfish resulted in an overall increase in the microbial load, vibrio levels increased only in oysters stored as shellstock. Although fecal coliform and total bacterial counts did not correlate with those for vibrios in fresh oysters, strong correlations were observed in oysters stored for 7 days, suggesting that these indicators may be useful in monitoring oyster quality when meats are stored for a limited time as shellstock.

Aeromonas↗
PubMed1983

Differential complement activation and susceptibility to human serum bactericidal action by Vibrio species.

The ability of Vibrio vulnificus to resist human serum bactericidal action and to activate human complement was compared with similar cultures of Vibrio cholerae and Vibrio parahaemolyticus. Both V. vulnificus and V. parahaemolyticus had similar survival rates in sera and were much more resistant to killing than was V. cholerae. In contrast, V. vulnificus activated significantly less serum complement than did V. cholerae and V. parahaemolyticus. The relative ability of V. vulnificus to survive in serum and activate less complement than other Vibrio spp. tested may be related to its ability to cause chronic tissue infections and septicemias.

Blood Bactericidal Activity↗