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Biomedical subjects

A W Kotula

Publications and source records attributed to A W Kotula.

At least 19 recordsLinked to original sources
PubMed1990

Effect of high temperature on infectivity of Toxoplasma gondii tissue cysts in pork.

To study the effect of high temperature on infectivity of Toxoplasma gondii tissue cysts, pork from infected pigs was mixed with infected mouse brains and homogenized thoroughly. Twenty-gram samples of infected homogenized meat were sealed in plastic pouches, pressed to a uniform thickness of 2 mm, and subjected to water-bath temperatures of 49, 52, 55, 58, 61, 64, and 67 C for 0.01, 3, 6, 9, 12, 24, 48, and 96 min. Treated samples were digested in HCl-pepsin solution and bioassayed in mice. Toxoplasma gondii tissue cysts remained viable at 52 C for 9.5 min but not for 9.5 min at 58 C; tissue cysts were generally rendered nonviable by heating to 61 C or higher temperature for 3.6 min. Tissue cysts survived once at 64 C for 3 min. These data demonstrate that T. gondii tissue cysts are less heat resistant than encysted Trichinella spiralis larvae.

Animals↗
PubMed1987

Subacute study of rats fed ground beef treated with aqueous chlorine: hematologic and clinical pathology.

Aqueous chlorine is effective in reducing surface spoilage bacterial counts on carcasses of slaughter animals and is presently being used for washing beef, pork, lamb, and poultry in some plants under an interim authorization. At present, at least three GRAS affirmation petitions have been submitted by industry groups for the continued use of chlorinated water on carcasses of slaughter animals. A dearth of information exists describing the hematological and clinical pathology associated with the consumption of such treated meat by mammals. Our research evaluated the response of rats to diets containing ground beef which had been treated with aqueous chlorine. Results of the hematologic evaluations demonstrated almost no effects associated with the feeding of rats with chlorine-treated meat for 92 d. There was a slight prolongation of the prothrombin time in all male groups fed the chlorine-treated meat. This prolongation was most pronounced in the 600 ppm group and was significant (p less than 0.05) when compared with the control males. In the absence of any other hematologic evidence, it is not possible to attribute the prolonged prothrombin time to the administration of the test compound. Prothrombin times of females did not differ significantly. The clinical chemistry and urine analysis yielded results wherein the values for the control and test rats are consistent with reported values for rats under standard laboratory conditions. On the basis of these hematologic and clinical data, there were no adverse effects on male or female rats fed ground beef treated with up to 600 ppm aqueous chlorine.

Animals↗
PubMed1984

Distribution of Trichinella spiralis larvae in selected muscles and organs of experimentally infected swine.

Thirty-two Hampshire-Yorkshire pigs (6 to 8 wk old) were inoculated with the Beltsville strain of Trichinella spiralis at a level of about 880 larvae/kg of body weight (about 15 kg). At about 100 kg, the pigs were slaughtered and 10-g samples of muscle and other tissues were digested in pepsin-HC1 and examined microscopically for T. spiralis larvae. The mean number of larvae recovered/gram was: tongue, 452; diaphragm, 391; obliquus abdominis internus, 130; serratus ventralis, 116; psoas major, 105; triceps brachii, 100; biceps femoris, 83; semitendinosus, 74; intercostal, 60; semimembranosus, 58 and longissimus dorsi, 37. The liver and spleen samples contained none. Larvae were found in one sample each of the blood, brain and kidney, in two samples of the heart, and in four samples of lymph tissue. Each of these samples was from a different pig except the positive samples of brain and heart, which were from the same pig. The larvae found in the blood, brain, kidney, heart and lymph were first stage larvae and, therefore, do not indicate migration of newborn larvae from the gut. The presence of these larvae in non-striated muscle tissue may have been due to contamination of the organs from infected skeletal muscle. These data confirmed previous reports of the distribution of the T. spiralis larvae among individual muscles of the carcass. Further, the data suggest that cross-contamination of organ tissue is possible during evisceration and, therefore, organ meat from infected swine cannot be assured to be free of T. spiralis larvae.

Animals↗
PubMed1984

The importance of Campylobacter jejuni to the meat industry: a review.

Campylobacter jejuni is a microorganism that only recently has been implicated in gastroenteritis in humans. As appropriate methods used for detection of the bacterium have been developed, the rates of illness caused by the pathogen were found to approach or surpass those attributed to Salmonella. Substantial evidence has been gathered to document that the route for human infection is through the ingestion of adulterated food and drink. Some slaughter animals harbor this potential pathogen among the intestinal flora and, consequently, transfer of the organism to carcasses and to the resulting meat products does occur. The most frequently implicated meat is poultry, with an incidence of recovery of C. jejuni from the store-bought poultry meat reported to be at least 50%. Red meat from slaughter animals have also yielded this bacterium from carcasses, but at lower incidence levels. Foodborne disease has been associated most frequently with the ingestion of raw milk, but poultry, hamburger, and other foods have all been implicated as potential sources. However, cause and effect relating the presence of C. jejuni in meat and human gastroenteritis has not been demonstrated. Additional research is needed to determine whether C. jejuni isolated from meat causes gastroenteritis and whether all strains of the organism are virulent. Recognition of C. jejuni as a potential meatborne pathogen by the meat industry is necessary, and appropriate sanitary practices to prevent passage of the organism through meat products should be implemented.

Adult↗
PubMed1983

Trichinella spiralis: effect of high temperature on infectivity in pork.

Twenty gram samples of homogenized Boston shoulder from swine experimentally infected with Trichinella spiralis were sealed in plastic pouches, pressed to a uniform thickness of 2 mm, and subjected to water bath temperatures of 49, 52, 55, 60, and 63 +/- 0.5 C for intervals of 2 min to 6 hr, especially within the interval of 0 to 15 min. These times included a period of about 1 min at the start and a period of about 1 min at the end for temperature equilibration. Treated samples were rapidly chilled to 25 C and then digested in a 1% pepsin-HCl solution at 37 C for 18 hr to recover T. spiralis larvae. The recovered larvae were suspended in 2 ml saline; 1 ml of this suspension was introduced into the stomach of each of two rats. The linear equation, log (time) = 17.3 -0.302 (temperature), was calculated from the time required at each temperature for the inactivation of T. spiralis larvae. The correlation coefficient for that relationship was r = -0.994. Larvae heated in the meat to 55 C for 4 min retained their infectivity, but were rendered noninfective after 6 min at 55 C. At 60 C, larvae were not infective after only 2 min (zero dwell time); whereas at 52 C, 47 min were required to render the larvae noninfective. Larvae in meat heated to 49 C were infective after 5 hr but not after 6 hr. These data demonstrate that the destruction of infectivity of T. spiralis is time-temperature related.

Animals↗
PubMed1982

Survival of Campylobacter jejuni inoculated into ground beef.

Ground beef was inoculated with mixed cultures of Campylobacter jejuni, and the samples were subjected to various cooking and cold-storage temperatures. When samples were heated in an oven at either 190 or 218 degrees C, approximately 10(7) cells of C. jejuni per g were inactivated (less than 30 cells per g) in less than 10 min after the ground beef reached an internal temperature of 70 degrees C. When the samples were held at -15 degrees C over 14 days of storage, the numbers of C. jejuni declined by 3 log10. When inoculated samples were stored with an equal amount of Cary-Blair diluent at 4 degrees C, no changes in viability were observed over 14 days of storage. Twenty-five times as much C. jejuni was recovered from inoculated ground beef when either 10% glycerol or 10% dimethyl sulfoxide was added to an equal amount of ground beef before freezing as was recovered from peptone-diluted ground beef. Twice as much inoculated C. jejuni was recovered from ground beef plus Cary-Blair diluent as was recovered from ground beef plus peptone diluent.

Animals↗
PubMed1982

Mineral composition of muscles of 1- to 6-year-old steers.

The diaphragm, longissimus, psoas major, semitendinosus and transversus abdominus muscles from eight or nine Angus steers were evaluated at each age of slaughter including 12, 18, 24, 30, 36, 48, 60 and 72 mo. The content of K, Fe, and Zn varied (P less than .01) with age of the steers. Ca, Na and Mg were not affected. The K content on a fat-free basis decreased from a high of 392 mg/100 g wet tissue at 24 mo of age to a low of 332 mg/100 g at 72 mo. Fe content increased with age from 2.00 mg/100 g of tissue at 12 mo to 3.73 mg/100 g at 72 mo. Concentrations of all minerals varied (P less than .01) among the five muscles evaluated. Feeding regimen had a significant effect on K, Fe and Zn, Steers fed entirely ad libitum had a higher K (17 mg/100 g more) and Fe (.19 mg/100 g more) content in their muscles than did the steers that were fed to gain .45 kg/d or those fed ad libitum for the last 6 mo before slaughter. Where significant, the magnitude of the difference in mineral content among age groups, muscles and feeding regimens was large enough to require that maturity, muscle and feeding regimen be specified when values for mineral content were reported.

Abattoirs↗
PubMed1982

Effects of feeding level on growth, composition of gain, carcass quality and mature body size in steers at ages up to six years.

Tissue gain and efficiency and carcass characteristics of seventy-eight Angus steers were compared on three feed intake regimens and serially slaughtered at 6 months to 6 years. The regimens were: (A) continuous ad ad libitum feeding, (B) restricted to gain about 0.45 kg daily and (C) restricted as in B until 6 months before slaughter then fed ad libitum. Steers, regardless of feeding regimen, made their greatest gains up to 12 months of age and became less efficient after that time. Steers fed ad libitum had the highest percentage of fat but the lowest percentage of lean and bone when compared with steers fed for restricted gain. Carcasses of the steers fed ad libitum contained more lean and fat at each slaughter age. Average daily gain, feed efficiency and percentage of lean and bone decreased with age; and feed intake, slaughter grade, dressing percent, taste panel desirability and percent of fat tended to increase with age. All steers reached their maximum growth in height at withers, depth of chest and length of body at about 3 years. Steers that were restricted up to 6 months before slaughter showed compensatory growth during their ad libitum feeding period and during the first 12 months of the study; protein and fat were produced most efficiently by this growth. It would appear that it is possible to modify fat deposition by changing feed intake level.

Adipose Tissue↗
PubMed1980

Virulence prediction of Yersinia enterocolitica by pyrolysis gas-liquid chromatography.

Pyrolysis gas-liquid chromatography (PGLC) was used to differentiate between HeLa cell-invasive and noninvasive strains of Yersinia enterocolitica and between Sereny-positive and -negative strains. A temperature-programmed gas-liquid chromatograph, equipped with a high-resolution Carbowax 20M coated capillary column, separated the volatiles from pyrolyzed whole cells preparations and cell wall fractions. The resulting pyrolysis elution patterns (pyrograms) were divided into 313 30-s time interval areas. The time interval areas were normalized in relation to the entire pyrogram area and were evaluated by stepwise linear discriminant analysis. The results of the PGLC-statistical analyses showed good correlation in prediction of the HeLa cell invasivity test. The technique of PGLC coupled with statistical analyses is objective, in contrast to traditional methods of determining pathogenicity of Y. enterocolitica.

Bacteriological Techniques↗
PubMed1979

Effect of sample transport systems on survival of bacteria in ground beef.

The effects of two transport systems and cryoprotective agents on the survival of bacteria in ground beef samples were evaluated. Survival of Clostridium perfringens in ground beef samples after simulated transport (72 h) was higher (about 99%) in Dry Ice than in Trans Temp shipping units (-3 degrees C). There were no significant differences between the two transport systems in survival of coliforms, Escherichia coli, Staphylococcus aureus, or aerobic bacteria. Mixing ground beef samples at a ratio of 1:1 (wt/vol) with 10, 20, or 30% buffered solutions of dimethyl sulfoxide or glycerol before freezing improved the survival of C. perfringens and coliforms in both transport systems. Recovery of E. coli was significantly higher with the addition of 10% dimethyl sulfoxide before Dry Ice transport. Addition of 10% dimethyl sulfoxide resulted in a 100% recovery of both S. aureus and aerobic bacteria from ground beef after simulated transport in Trans Temp shipping units. The use of cryoprotective agents can improve the survival of bacteria during transport of ground beef samples.

Animals↗
PubMed1979

Differentiation of selected Enterobacteriaceae by pyrolysis-gas-liquid chromatography.

Pyrolysis-gas-liquid chromatography was used to differentiate selected species of Enterobacteriaceae. Individual cultures of Salmonella typhi, Hafnia alvei, and Proteus vulgaris, and 12 strains of Yersinia enterocolitica were grown in nutrient broth. After harvest and lyophilization, the bacterial samples were pyrolyzed at 900 degrees C, and their volatile fractions were separated on a 50-m capillary column coated with Carbowax 20M. The resulting pyrolysis elution patterns (pyrograms) of the four species were monitored on an integrating console, which was coupled with the chromatographic detector. The pyrograms were divided into 312 30-s time interval areas, and each interval area was normalized in relation to the area of the entire curve. The normalized areas were evaluated by stepwise linear discriminant analysis, and the discriminating component coordinates were used to generate a plot of the canonical variables. Distinct clustering patterns allowed discrimination among the four genera of Enterobacteriaceae studied. The tight clustering of the 12 Y. enterocolitica strains suggests the advantage of pyrolysis-gas-liquid chromatography over traditional approaches for species identification.

Bacteriological Techniques↗
PubMed1978

Differentiation of Salmonella Serotypes by pyrolysis-gas-liquid chromatography of cell fragments.

Pyrolysis-gas-liquid chromatography (PGLC) of whole cells and cell fragments was used to differentiate 10 Salmonella serotypes. Lyophilized samples (200 microgram) of whole cells, cell walls, flagella, and deoxyribonucleic acid from each serotype were analyzed in duplicate by PGLC. Pyrochromatograms recorded as pyrolytic elution patterns represented thermal fragmentation products of the samples. Mathematical expressions of percent similarity and percent conformity were calculated for all possible pair combinations of the 10 serotypes. Stepwise discriminant analysis of the PGLC data showed that 100 percent correct classification of the 10 serotypes was possible from the flagella or deoxyribonucleic acid pyrochromatograms. The classification matrix of the whole-cell data showed a 90 percent correct classification. PGLC of cell fragments may provide useful information for taxonomic studies of Salmonella and other microorganisms.

Cell Wall↗
PubMed1977

Reduction of Salmonella and fecal contamination of pork during swine slaughter.

Experiments were designed to reduce Salmonella and fecal contamination of pork, using several sanitizing methods and agents. Sanitizing the hauling vehicle and holding pens with chlorine or quaternary ammonium compounds proved ineffective in reducing carcass contamination. When the eviscerator wore a plastic glove and sanitized his knife in 82-C water before using it on each carcass, contamination was reduced about 50%. Sanitizing the eviscerator's knife in 500-ppm chlorine solution adjusted to a pH of 6.0, or in 25-ppm iodine solution reduced contamination approximately 75%.

Abattoirs↗
PubMed1976

Bacteriological quality and shelf life of ground beef.

The bacteriological quality of unfrozen raw ground beef was evaluated after 0, 3, 6, 9, 12, 15, and 18 days of storage at 29 +/- 1 F (-1.7 +/- 0.6 C). At the time of fabrication, all of the ground beef samples contained 10(6) or fewer total aerobic and psychrotrophic bacteria/g; 81% contained 100 or fewer coliforms/g; 94% contained 100 or fewer Escherichia coli/g; and all of the samples contained 100 or fewer coagulase-positive Staphylococcus aureus and Clostridium perfringens/g. Total aerobic and psychrotrophic bacteria increased by 1 log between 3 and 18 days of storage. Coliform and E. coli counts decreased during storage, whereas coagulase-positive S. aureus and C. perfringens counts did not change significantly. These data indicate that meat processors, wholesalers, and retailers could improve the bacteriological quality and prolong the shelf life of ground beef packaged in oxygen-impermeable film if the temperature of product never exceeded 29 +/- 1 F (-1.7 +/- 0.6 C).

Aerobiosis↗