PubMed Health⌕ Search

Biomedical subjects

E B MASUROVSKY

Publications and source records attributed to E B MASUROVSKY.

5 recordsLinked to original sources
PubMed1963

Effects of substerilization doses of Co-60 gamma radiation on the cold-storage life extension of shucked soft-shelled clams and haddock fillets.

Total aerobic-facultative and anaerobic (clostridia) macrocolony count data are presented, with analysis and interpretation, for both haddock fillets and shucked soft-shelled clams which received doses of from 50,000 to 800,000 rad of Co(60) gamma rays. These data indicated that haddock fillets may be maintained in good condition at refrigeration temperatures above freezing for about 1 week at 6 C, and approximately 2 weeks at 0 C, when treated with from 50,000 to 150,000 rad of ionizing radiation. In the dose range from 200,000 to 350,000 rad, the storage life may be extended up to some 2 weeks at 6 C, and 3 weeks at 0 C. Treatments in the dose range from 400,000 to 500,000 rad may defer spoilage for about 1 month, and doses of 550,000 to 650,000 rad afford protection against bacterial spoilage up to approximately 1.5 months. At the high substerilization doses of 700,000 to 800,000 rad, haddock fillets may be held for from 2 to 3 months in refrigerated storage before becoming unfit for marketing and consumption. Shucked soft-shelled clams can be held for about 2.5 weeks at 0 C and close to 12 days at 6 C, when given low substerilization doses of from 50,000 to 150,000 rad of ionizing radiation. At doses of from 200,000 to 350,000 rad, the clams may be preserved effectively for periods up to 3 weeks at 0 or 6 C, and some 6 weeks at these temperatures with doses of about 450,000 rad. With treatments of 500,000 to 600,000 rad, the storage life may be extended for some 2 months, and at doses of 650,000 to 800,000 rad the shucked clams remain in a good state of preservation for up to 3 months at temperatures of 0 to 6 C. Thus, it would appear that shucked soft-shelled clams may be maintained for significantly longer periods in refrigerated storage than haddock fillets when the same radiation treatments are applied to each product. Clostridia levels in both products were relatively low initially, and were reduced significantly by the gamma rays at the doses studied. Moreover, those clostridia that survived the radiation treatments were found to remain at safe, low levels during the various periods in refrigerated storage employed for these products, a very encouraging result from the public health, as well as commercial, standpoint.

Animals↗
PubMed1963

Changes in the microflora of haddock fillets and shucked soft-shelled clams after irradiation with Co-60 gamma rays and storage at 0 C and 6 C.

Frequency distribution patterns of aerobic-facultative microflora, obtained by random selection of macrocolonies from samples of haddock fillets and shucked soft-shelled clams before and after treatment with doses of from 50,000 to 800,000 rad of Co(60) gamma rays, are presented, with analyses and interpretation. The data showed that a decided change occurred in the constitution of the microbial populations of both products: from a mixed gram-negative-gram-positive flora to a predominantly gram-positive flora immediately after irradiation. The great majority of these surviving microorganisms were micrococci, sporeforming bacilli, and certain yeasts, molds, and actinomyces. During storage at refrigeration temperatures above freezing, the microflora changed from the descendants of the more radioresistant gram-positive species to the more prolific gram-negative psychrophilic species that flourish at these low temperatures. Micrococci and gram-positive rods declined somewhat during the rise of the actively proteolytic-lipolytic pseudomonads and related species, but still remained at high enough levels to contribute significantly to the spoilage observed at different times in storage. The eventual spoilage of haddock fillets was characterized by discoloration of the cream-white tissue with water-soluble yellow, green, and red bacterial pigments; degradation of the tissue, by proteolytic and other microbial enzymes, to a watery, flaccid mass; and formation of volatile compounds that smelled putrid, rancid, and generally foul and pungent. Shucked soft-shelled clams displayed a different spoilage pattern, changing to a variegated brown-gray and forming a matted or loose gelatinous mass from which arose stale, acrid, putrid, sulfurous odors. These differences are believed to be attributable to the varied biochemical nature of the tissues involved, the Eh potential within the tissues, the time sequence of microfloral change, and the species and types of microorganisms associated with each product. Staphylococci were present in small numbers in some of the samples tested, but did not appear to be species of public health significance. Gram-negative enteric rods were also encountered, but were considered to be of doubtful public health importance. More detailed investigations, designed to study the effects of Co(60) gamma radiations on such microbes in sea foods, would be useful in assessing the problem further.

Animals↗
PubMed1963

RADIATION-RESISTANT, PIGMENTED COCCUS ISOLATED FROM HADDOCK TISSUE.

Davis, Norman S. (Massachusetts Institute of Technology, Cambridge), Gerald J. Silverman, and Edmund B. Masurovsky. Radiation-resistant, pigmented coccus isolated from haddock tissue. J. Bacteriol. 86:294-298. 1963.-An orange-brown, catalase-positive coccus was isolated from irradiated haddock. The new coccus was found to consist of rough and smooth strains as well as strains possessing appreciably less pigment. The smooth strain (248) was more radioresistant to gamma radiation than the rough strain, and at higher radiation doses was of comparable resistance to Micrococcus radiodurans. The less-pigmented strain was as radio-resistant as its parent strain (248). Although morphologically similar to other, but less-resistant, micrococci, the coccus differed by growing slowly on solid media, and was unable to grow in 7% salt. It was distinguished from M. radiodurans by being smaller in size and in being capable of reducing nitrate to nitrite and hydrolyzing gelatin.

Animals↗