Biomedical subjects

T Solberg

Publications and source records attributed to T Solberg.

22 records · Page 2Linked to original sources

PubMedDate not supplied

Testing mammography equipment: evolution over a 4-year period.

The results of quality control (QC) tests on 70 mammography units in Southern California from 1986 to 1990 are reported. Thirteen facilities, selected because they housed all of the mammography units in three communities involved in a National Institutes of Health research project, had their units tested twice at an interval of 1 year. Fourteen self-selected units were also tested twice at intervals ranging from 1-3 years. Forty-three self-selected units in 31 additional facilities had testing only once. All 70 units underwent measurement of focal spot size or resolution, tube output, half-value layer (HVL), automatic exposure control (AEC) accuracy, relative kVp accuracy, mean glandular dose, and imaging of several test objects. The test results for the units tested once showed no significant differences compared to those tested twice. For the latter, once the units were tested and determined to be acceptable, retesting showed differences only in overall film optical density, dose, and AEC performance.

Ambulatory Care Facilities↗

PubMedDate not supplied

[Quality changes in iced shrimps (Pandalus borealis). I. Changes in the contents of trimethylamine oxide and volatile nitrogen bases and bacteria in raw shrimps after different storage periods compared with organoleptic examinations (author's transl)].

On the basis of two experiments on the storage of raw shrimps (Pandalus borealis) in ice and on samples taken out from different trawlers after different days at sea, we have attempted to find the criteria of choice for the lower limit of quality of raw shrimps which are meant for further processing for human consumption. A content of TVN of approximately 50 mg/100 g peeled shrimp and a content of TMA-N of approximately 10 mg/100 g peeled shrimp probably represent such an objective lower limit if a comparison with organoleptic assessment is made. Assuming suitable storage conditions, this corresponds to a maximum period of 7 days. In this paper we have also attempted to find the content of TMAO in fresh raw shrimps from different fishing grounds in the Barents sea and off the Eastern coast of Greenland. The content of TMA-N was found to vary from 166 to 211 mg/100 g peeled shrimp.

Bacteria↗

PubMedDate not supplied

[Quality changes in iced shrimps (Pandalus borealis). II Changes in the contents of trimethylamine oxide and volatile nitrogen bases during automatic boiling and peeling (author's transl)].

Post mortem trimethylamine oxide (TMAO) in marine animals is reduced to trimethylamine (TMA), and the degradation of proteins causes an increase in the ammonia (NH3) content. During ice-storage NH3 and TMA usually make up the major part of the total content of volatile nitrogen bases (TVN) which are formed during the degradation process. The formation of TMA and NH3 is probably caused mainly by bacterial enzymes. The contents of TMA and TVN in marine fish and shrimps are important objective criteria in supporting organoleptic examinations of such raw materials. During automatic boiling, peeling and rinsing processes in shrimp factories, some of these water-soluble and volatile compounds will be extracted by the boiling water and possibly evaporated. In this investigation we have attempted to estimate the loss of TMAO, TMA and TVN in shrimp muscle during this automatic processing. The investigation includes experiments in the laboratory (Table I, Figure 1) and in two factories (Table II-III, Figure 2-3). The results show that about 50% of the contents of TMAO-N, TMA-N and TVN probably will be lost from the shrimps during automatic processing. Adding approximately 100% TMA-N and TVN to the analysed contents in boiled, peeled and rinsed shrimps will therefore probably give the same level of these compounds as that found in the raw shrimps used. An accurate measurement of the TMA- and TVN-content in shrimp produced under known condition in North-Norwegian shrimps factories could give an objective indication of the quality of the raw shrimps used. In accordance with Norwegian shrimp regulations, only the fresh, healthy shrimps are allowed to be produced.

Food Handling↗

PubMedDate not supplied

[Quality changes in iced shrimps (Pandalus borealis). III. Indole and pH in shrimps caught in the Barents Sea compared with shrimps caught in the Far East (author's transl)].

The content of indole and the pH have been determined post mortem in shrimps (Pandalus borealis) caught in the Barents Sea and in shrimps caught outside Malaysia, India and Taiwan. These two criteria were compared with organoleptic assessment and the contents of volatile nitrogen bases (ammonia, trimethylamine) and living bacteria. For shrimps caught in the Barents Sea, both raw shrimps stored in ice and processed (broiled, peeled and single-frozen) shrimps were investigated. The results showed that only low levels of indole had been formed during ice-storage. Not until an advanced state of spoilage could a distinct increase in the indole content in raw and in boiled, peeled shrimps be discerned. pH increased slowly and varied in the area between acceptable and not acceptable quality. Neither the indole content nor the pH seems therefore to be a useful criterion for quality assessment either of raw shrimps caught in the Barents Sea or of such shrimps after processing (boiling and peeling). Most of the samples of boiled, peeled shrimps from the Far East were assessed organoleptically as less good-spoiled, and bacterial growth was significant. The content of trimethylamine oxide and volatile nitrogen was low, while the content of indole was high and exceeded 25 microgram/100 g in 8 or 14 samples. This is the upper limit for import in USA. The content of indole seems to be an important quality criterion for shrimps caught in warmer countries. The content of indole exceeded 25 microgram/100 g in some samples which were assessed organoleptically as acceptable. The pH was lower in brine-treated shrimps than in the others.

Animals↗