ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14360.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Volatile components of three varieties of tomatoes processed in plain tin and enamel can linings at 0, 1, 4 and 8 months storage time were determined. A recently developed extraction method was used for separation and collection of volatiles free of moisture. This method allowed the study of small quantities of materials in a reasonable time. Multiple sampling of the vapor aliquots permitted qualitative and quantitative analysis.The greatest qualitative and quantitative differences in volatile composition were noted between the raw and heat processed samples. Methyl sulfide which was absent in the fresh fruit was formed during the heat process. The concentrations of acetaldehyde, acetone, methanol, and hexanal were significantly altered by processing. Differences between varieties were due to varying quantities of individual constituents but quantitative differences between can lining were less apparen

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14361.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—The levels of certain chemical and physical constituents of the Longissimus dorsi (LD), Semimembranosus (SM) and Triceps brachii (TB) muscles from 10 half‐sib Hereford steer carcasses were determined and related to sensory evaluations made by a laboratory panel. Highly significant (P<.01) differences due to animals and panel members were found. However, no statistically significant differences in tenderness, juiciness, flavor and an overall acceptability score were observed between the muscles. This was apparently the result of the large panel member × muscle interaction (P<.01). Certain significant differences (P<.01) in tenderness between the muscles were detected by the Warner‐Bratzler (WB) shear. Sensory panel evaluations strongly suggested an undesirable effect of lactic acid and pigment concentration on muscle acceptability. These were the only muscle constituents studied which varied significantly (P<.05) in concentration between muscles. Variable, but small, negative correlations between panel traits and the acid and alkaline phosphatase concentrations of the muscle were dete

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14362.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—A variety of laboratory cured hams were inoculated with 103−106cells ofS. aureusstrain S‐6 and incubated at 10, 22 and 30°C anaerobically for up to 16 weeks. Enterotoxin‐B was detected by gel‐diffusion in hams with original pH over 5.30, up to 9.2% NaCl (brine) and 0.54 ppm undissociated nitrous acid. There was better toxin production at 30° than at 22° or 10°C. Toxin was detected at 10°C after at least 2 weeks incubation and in most samples after 8 weeks when pH was greater than 5.6. Toxic hams had more than 4 × 106cells/g. Contaminants were always less than 105/g. Tween 80 inhibited toxin production at 30° but not at 10°C. Toxic hams looked normal even after 2 months i

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14363.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—During the aging of fiber pieces prepared from bovine sternomandibularis muscles, a loss of adhesion occurs between adjacent myofibrils. This is evidenced by increased readiness of fiber pieces to distintegrate into individual myofibrils during a period of standard disruption. Alterations also appear within the myofibrils themselves in the regions of the Z lines, sometimes leading to the apparent dissolution of this structure. Ethylenediamine tetraacetate present in the suspensions during storage not only prevents these changes, but also preserves the refractory character of the fiber pieces. Meat aging is considered therefore to be due to disruption and possible dissolution of Z‐line material, leading to a weakening of inter‐myofibrillar linkages probably located at the junctions of adjacent Z lines, and to loss of tensile strength of the myofibrils thems

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14364.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—The effect of 28 microorganisms on the accumulation of hydroperoxides and monocarbonyls in fresh fat has been determined.Pseudomonas ovalis, Micrococcus freudenreichiiand two strains ofStreptomycesincreased the concentration of peroxides;M. freudenreichiialso produced an increase in 2‐enals, 2, 4‐dienals, and alkanals.Pseudomonas fragi, Geotrichum candidum, andCandida lipolyticaproduced an increase in alkanals and methyl ketones. All other cultures either removed the small amount of peroxides and monocarbonyls in fresh fat and prevented any build‐up or had no effect. The ability of microorganisms to oxidatively attack fats was not related to their oxidase reactions or their ability to produce lipase. Differences in oxidative activity on fresh and rancid lard are di

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14365.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—The effects of pH and the addition of sodium chloride (NaCl) or sodium nitrite (NaNO2) to trypticase‐peptone‐glucose (TPGI and trypticase‐peptone‐sucrose‐yeast extract (TPSY) media upon spore outgrowth were investigated using seven Type EClostridium botulinumstrains. An inoculum of 1.0 × 105spores/ml was used and the pH was adjusted with hydrochloric acid to cover the range of 5.2 to 6.6. To define salt tolerance, NaCl was added to the media at intervals of 0.5% in the range of 2.0 to 5.0% and at 0.1% intervals in the 4.5 to 5.0% range. The effect of NaNO2was investigated with the addition of 100 and 200 ppm NaNO2to the media. Samples were incubated at 30, 15.6, 10, 7.2, 5.0 and 3.4°C. Outgrowth of all strains tested was inhibited at pH 5.2 at 15.6°C. Inhibition occurred at higher pH at lower temperatures. None of the strains showed outgrowth with 4.87% NaCl in the media at any of the incubation temperatures used. Addition of 100 and 200 ppm NaNO2to the media inhibited the outgrowth of the Minneapolis, 517, 26080 and A6247 strains but not the Kalamazoo and Seattle

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14366.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—The inhibition of outgrowth of spores ofClostridium botulinumType E by the addition of different concentrations of various solutes to a trypticase‐peptone‐sucrose‐yeast extract medium (TPSY) was studied at different incubation temperatures. Solutes added to TPSY medium were sodium chloride (NaCl), sodium formate (NaCOOH), potassium chloride (KCI), sucrose and glucose. Incubation was at 30, 21.1, 15.6, 10 and 7.2°C, and growth was confirmed by mouse toxin assay. The effect of the solutes on the equilibrium relative humidities (ERHI of the various media was measured using the graphical interpolation method and expressed as water activity (aw). The possibility of an osmotic effect was also investigated. The molar (M) concentrations and osmotic pressures of the different solutes were calculated and related to the approximate inhibitory concentrations of 5.0% NaCl (aw0.975), 6.0% KCI (aw0.974), 5.5% NeCOOH (aw0.9711, 38.5% sucrose (aw0.976) and 22.5%. glucose (aw0.970).The inhibitory salt concentrations were approximately 0.80 M and produced osmotic pressures of about 36.0 atmospheres. The approximate osmotic pressure of the inhibitory 1.12 and 1.24 M sucrose and glucose solutions were 25.08 and 27.97 atmospheres respectively.Growth response decreased as the incubation temperature decreased as measured by delayed outgrowth times and in decreased amount of cellular material produced by the Type E strain

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14367.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Bacterial spores grown in medium containing calcium chloride were found to be very thermoresistant. If raw baby clams were collected from muds with a high calcium content, the canned product usually spoiled. Sea‐bottom muds high in calcium may, therefore, have an effect upon the thermoresistance of the spores. There was no relationship between iron and magnesium content of muds and the spoilage of the canned product. The amount of hydrogen sulfide was in proportion to the organic matter and humus content of the muds. Unless chemical or bacteriological factors are involved, the hydrogen sulfide content of the mud itself would not be sufficient to cause spoilage of the canned clams. Qualitative and quantitative tests for sulfate and sulfite ions showed an inverse relationship with the amount of hydrogen sulfide. This might be a result of reduction of sulfate in the muds.Thermophilic spore formers are widely distributed in all locations of the Ariake Sea. If baby clams are collected from this area and improperly cleaned, they may contain enough bacteria to cause spoilage in the canned product. The spore‐forming bacteria isolated from muds were classified and consisted of 83%Clostridiumand 17%Bacillusg

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14368.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—A surgical isolator technique was developed for obtaining sterile muscle tissue from a beef carcass. This tissue was compared during refrigerated storage with a general inoculum tissue sample, a low level general inoculum sample, a sample inoculated withPseudomonasand anAchromobactersample. Protein fractionation revealed a decrease in sarcoplasmic protein for all treatments during storage. An initial rise, followed by a relatively constant value in the myofibrillar fraction, was also observed for all treatments.The stroma fraction, the nonprotein nitrogen fraction, percent free water, pH and emulsifying capacity of the aseptic and low level inoculated samples remained fairly constant throughout storage. The higher level inoculated samples decreased slightly in stroma protein during storage and increased in nonprotein nitrogen late in the storage period, These same treatments increased in pH, decreased in percent free water and increased in emulsifying capacity (late in storage

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb14369.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY