PubMed Health⌕ Search

Biomedical subjects

D C Riordan

Publications and source records attributed to D C Riordan.

At least 19 recordsLinked to original sources
PubMed2001

Efficacy of washing with a commercial flatbed brush washer, using conventional and experimental washing agents, in reducing populations of Escherichia coli on artificially inoculated apples.

Conventional and experimental washing formulations were applied with a commercial flatbed brush washer under conditions representative of commercial practice to determine their efficacy in decontaminating apples inoculated with a nonpathogenic Escherichia coli strain. Golden Delicious apples (18 kg) inoculated with E. coli were mixed with approximately 109 kg of uninoculated Fuji apples (distinctly different in appearance) in a wet dump tank containing 1,325 liters of water at 20 degrees C for 15 min. The combined apples were washed in a flatbed brush washer with the following washing solutions: water at 20 degrees C, water at 50 degrees C, 200 ppm of chlorine (pH 6.4) at 20 degrees C, 8% trisodium phosphate at 20 degrees C, 8% trisodium phosphate at 50 degrees C, 5% hydrogen peroxide at 20 degrees C, 5% hydrogen peroxide at 50 degrees C, 1% APL Kleen 245 at 50 degrees C, and two-stage washing treatments using the combination of 1% APL Kleen 245 at 20 or 50 degrees C followed by 5% hydrogen peroxide at 35 or 50 degrees C. None of the washing treatments tested under the conditions of this experiment significantly reduced the E. coli populations on the inoculated apples or in cider made from these apples, probably as a consequence of the inability of this washing system to inactivate or remove the bacterial cells in inaccessible calyx and stem areas of apples. These results are important because they demonstrate the need for new fruit washing technology that can overcome this limitation. Also, there was no significant cross-contamination of the Fuji apples in the dump tank. Significant cross-contamination of cider, made with uninoculated apples, occurred in the hammer mill and/or the press cloth when these units were not sanitized following a trial with inoculated apples.

Colony Count, Microbial↗
PubMed2001

A study of U.S. orchards to identify potential sources of Escherichia coli O157:H7.

The association of unpasteurized apple cider with Escherichia coli O157:H7 foodborne illness has led to increased interest in potential reservoirs of this pathogen in the orchard. Fourteen U.S. orchards were surveyed in autumn 1999 to determine the incidence and prevalence of E. coli O157:H7, E. coli, total aerobic microflora, and yeasts and molds. Fruit samples (n = 63) (eight apple and two pear varieties) and soil, water, and fecal samples were collected. Samples were plated on (i) tryptic soy agar for total mesophilic aerobic count, (ii) E. coli and coliform Petrifilm for total coliforms and E. coli, and (iii) yeast and mold Petrifilm. Samples positive for coliforms and E. coli were enriched and tested for E. coli O157:H7. Fruit was also tested for internalization of microflora by aseptically removing the core, stem, and calyx areas, and the individual sections were assessed for the categories of microflora listed above. E. coli was detected in soil and water and in 6% of fruit samples (three pear samples and one apple sample), generally collected from areas previously designated as high risk in this study. However, no E. coli O157:H7 was found. Coliforms were found in 74% of fruit samples and were internalized in the cores of 40% of fruit tested. Yeasts and molds were internalized in 96.7% of samples and aerobic bacteria in 89.6%. E. coli was not found to be internalized. Total aerobic counts and total coliforms were higher in dropped and damaged fruit (P < 0.05). Findings suggest that dropped or damaged fruit should not be included in fruit designated for the production of unpasteurized juice or for the fresh or fresh-cut market. In addition, orchards should be located away from potential sources of contamination, such as pastures.

Bacteria, Aerobic↗
PubMed2000

Effect of pH on survival, thermotolerance, and verotoxin production of Escherichia coli O157:H7 during simulated fermentation and storage.

Heat treatment is increasingly being introduced to fermented meat processing, since the acid tolerance properties of Escherichia coli O157:H7 can permit this organism to survive traditional processing procedures. This study investigated the effect of growth pH and fermentation on the thermotolerance at 55 degrees C of E. coli O157:H7 in a model fermented meat system. E. coli O157:H7 (strain 380-94) was grown at pH 5.6 or 7.4 (18 h at 37 degrees C), fermented to pH 4.8 or 4.4 in brain heart infusion broth, and stored for 96 h. Cells grown at pH 5.6 had higher D values at 55 degrees C (D55 degrees C) than cells grown at pH 7.4 (P < 0.001). Cells fermented to pH 4.8 had higher D55 degrees C than those fermented to pH 4.4 (P < 0.001). Cells fermented to pH 4.8 demonstrated an increase in D55 degrees C during storage (P < 0.001), whereas cells fermented to pH 4.4 showed a decrease in D55 degrees C during the same period (P < 0.001). The effect of growth pH on verotoxin production by E. coli O157:H7 was assessed using the verotoxin assay. Cells grown at pH 5.6 had lower verotoxin production then cells grown at pH 7.4. This effect was not sustained over storage. These results indicate that a lower growth pH can confer cross-protection against heat. This has implications for the production of acidic foods, such as fermented meat, during which a heating step may be used to improve product safety.

Animals↗
PubMed2000

The survival of Escherichia coli O157:H7 in the presence of Penicillium expansum and Glomerella cingulata in wounds on apple surfaces.

The survival of Escherichia coli O157:H7 in the presence of one of two plant pathogens, Penicillium expansum and Glomerella cingulata, in wounds on apples was observed during 14 days storage at room temperature (RT) and at 4 degrees C. The aim of this work was to determine if changes in apple physiology caused by the proliferation of fungal decay organisms would foster the survival of E. coli O157:H7. Trials were performed where (A) plant pathogens (4 log10 spores) were added to apple wounds 4 days before the wounds were inoculated with E. coli O157:H7 (3 log10 CFU g(-1) apple) (both RT and 4 degrees C storage), (B) plant pathogens and E. coli O157:H7 were added on the same day (both RT and 4 degrees C storage), and (C) E. coli O157:H7 was added 2 days (RT storage) and 4 days (4 degrees C storage) before plant pathogens. In all trials E. coli O157:H7 levels generally declined to <1 log10 at 4 degrees C storage, and in the presence of P. expansum at 4 degrees C or RT. However, in the presence of G. cingulata at RT E. coli O157:H7 numbers increased from 3.18 to 4.03 log10 CFU g(-1) in the apple wound during trial A, from 3.26 to 6.31 log10 CFU g(-1) during trial B, and from 3.22 to 6.81 log10 CFU g(-1) during trial C. This effect is probably a consequence of the attendant rise in pH from 4.1 to approximately 6.8, observed with the proliferation of G. cingulata rot. Control apples (inoculated with E. coli O157:H7 only) were contaminated with opportunistic decay organisms at RT during trials A and B, leading to E. coli O157:H7 death. However, E. coli O157:H7 in control apples in trial C, where no contamination occurred, increased from 3.22 to 5.97 log10 CFU g(-1). The fact that E. coli O157:H7 can proliferate in areas of decay and/or injury on fruit highlights the hazards associated with the use of such fruit in the production of unpasteurized juice.

Colony Count, Microbial↗
PubMed1998

Survival of Escherichia coli O157:H7 during the manufacture of pepperoni.

This study investigated the growth and survival of Escherichia coli O157:H7 during the manufacture of pepperoni to determine whether a 5-log10-unit decline in numbers, as recommended by the U.S. Food Safety and Inspection Service (FSIS), could be achieved. A range of pepperoni formulations with variations in salt (2.5 to 4.8%) and sodium nitrite (100 to 400 ppm) levels, and with pH (4.4 to 5.6) adjusted by manipulation of dextrose concentrations were prepared. The batters produced were inoculated with E. coli O157:H7 380-94 at a level of approximately 6.70 log10 CFU/g; changes in pathogen numbers, pH, titratable acidity, and sodium nitrite concentrations were monitored during fermentation and drying. With the standard commercial formulation (i.e., 2.5% salt, 100 ppm sodium nitrite, pH 4.8) E. coli O157:H7 numbers declined by approximately 0.41 log10 CFU/g during fermentation and a further 0.43 log10 CFU/g during subsequent drying (7 days). A regression equation was fitted to the data which showed significantly (P < 0.001) greater reductions in pathogen numbers in samples with increased salt and sodium nitrite contents and lowered pH. However declines were in all cases less than the target reduction of 5 log10 CFU/g.

Colony Count, Microbial↗
PubMed1992

Staff attitudes towards patients: the influence of causal attributions for illness.

The aim of this study is to determine whether staff attitudes towards patients are affected by staff causal attributions. Forty-eight nurses and doctors were presented with five case histories of patients suffering from lung cancer, liver cirrhosis myocardial infarction, breast lump and cervical cancer. There were two versions of each case: one patient had followed and the other had ignored a relevant health action (e.g. not smoking in the lung cancer patients). Subjects responded to just one version of each case. For all five conditions, staff had significantly more negative attitudes towards patients who had not undertaken a relevant health behaviour compared with patients who had undertaken a relevant health behaviour. A second group of nurses rated it as more likely that this latter group of patients could have prevented their illnesses. The results suggest that information about a patient's health habits prior to illness influence staff attitudes to that patient. Evidence is presented suggesting that the effect of this information is mediated by perceived controllability of the illness, as predicted by an attributional model of helping behaviour.

Attitude of Health Personnel↗
PubMed1992

Modification of the L'Episcopo procedure for brachial plexus birth palsies.

We reviewed 19 children who had undergone a new modification of the L'Episcopo procedure for obstetric brachial plexus palsy. Through an axillary approach the latissimus dorsi tendon was re-routed anteriorly to the humerus and then anastomosed to the teres major tendon routed posteriorly. At an average follow-up of four years two months, the mean increase in shoulder abduction was 26 degrees and the mean increase in external rotation was 29 degrees. No neurovascular injury or postoperative infection occurred. Two patients had complications, and five did not gain from the procedure. The modified operation was relatively easier to perform and provided excellent cosmesis.

Birth Injuries↗
PubMed1984

Intrinsic paralysis of the hand.

Two types of tendon transfers are described that can be used to treat paralysis of the hand caused by either a low ulnar nerve paralysis or a combined median and ulnar nerve paralysis.

Hand↗
PubMed1983

Tendon transfers in hand surgery.

The need for skilled surgeons, trained in the proper techniques of hand surgery, to reconstruct paralytic hands has been emphasized. The most useful techniques for radial nerve paralysis have been found to be transfer of the pronator teres to the extensor carpi radialis brevis, of the flexor carpi ulnaris into the extensor digitorum communis, and of the palmaris longus into a rerouted extensor pollicis longus. For treatment of clawhand, the Bunnell sublimis transplantation is recommended for mild deformities in patients without normally hyperextensible joints and for patients who need a powerful flexor force on the proximal phalanges for strong gripping of tools, such as those used by mechanics and carpenters. The modified Fowler extensor transplant is also recommended for cases detected early and can be used for more advanced cases. The recent Brand procedure, which uses the extensor carpi radialis longus and a four-tailed tendon graft to the palmar side through the carpal tunnel and lumbrical canal, is also recommended, but further experience is needed for full evaluation of this procedure. Of the static methods of overcoming clawed hands, the Zancolli procedure of advancing the palmar plate proximally provides good results, although it probably should be reserved for those patients in whom no active tendon transfer can be provided. Long-term experience has shown that this capsulodesis seems to gradually stretch out and allow some recurrence of the hyperextension of the proximal joint. The Fowler tenodesis, which has an advantage over the Riordan method, is a semiactive tenodesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Hand Deformities, Acquired↗