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Biomedical subjects

B S Emswiler

Publications and source records attributed to B S Emswiler.

8 recordsLinked to original sources
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↗
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↗
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↗
PubMed1976

Sublethal heat stress of Vibrio parahaemolyticus.

When Vibrio parahaemolyticsu ATCC 17802 was heated at 41 degrees C for 30 min in 100 mM phosphate-3% NaCl buffer (pH 7.0), the plate counts obtained when using Trypticase soy agar containing 0.25% added NaCl (0.25 TSAS) were nearly 99.9% higher than plate counts using Trypticase soy agar containing 5.5% added NaCl (5.5 TSAS). A similar result was obtained when cells of V. parahaemolyticus were grown in a glucose salts medium (GSM) and heated at 45 degrees C. The injured cells recovered salt tolerance within 3 h when placed in either 2.5 TSBS or GSM at 30 degrees C. The addition of chloramphenicol, actinomycin D, or nalidixic acid to 2.5 TSBS during recovery of cells grown in 2.5 TSBS indicated that recovery was dependent upon protein, ribonucleic acid (RNA, and deoxyribonucleic acid (DNA) synthesis. Penicillin did not inhibit the recovery process. Heat-injured, GSM-grown cells required RNA synthesis but not DNA synthesis during recovery in GSM. Chemical analyses showed that total cellular RNA decreased and total cellular DNA remained constant during heat injury. The addition of [6-3H]uracil, L-[U-14C]leucine, and [methyl-3H]thymidine to the recovery media confirmed the results of the antibiotic experiments.

Bacterial Proteins↗