ABSTRACT
A study was performed on the bacteriological, chemical and organoleptic characteristics of antartic krill (Euphausia superba) stored at 0-2 degrees C. After 6-8 hours of storage a dark color started in the head and legs and spread slowly to the tail. Within 24 hours 17% of the total nitrogen was lost by hepatopancreas autolisis. After 72 hours the krill became inedible due to strong amoniacal odor and flavor. These changes were associated with the multiplication of aerobic psychrophilic bacteria. The bacterial counts of freshly caught krill ranged between 3,7 X 10(2)/g and 2,5 X 10(5)/g at 21 degrees C. During storage at 0-2 degrees C the counts gradually increased and off-odors were produced when they reached values of 10(6)/g at 21 degrees C. The total volatile bases content of freshly caught krill, 0.018 to 0.038%, increased considerably during storage reaching values of approximately 0.100% when off-odors became noticeable and 0.200% or more when the odor was clearly ammoniacal. Pseudomonas spp Gp. II (Shewan) were predominant in the bacterial flora of the freshly caught krill along with Moraxella spp Alcalígenes spp, Vibrio spp, Micrococcus spp and coryneforms. The spoilage flora developed during cold storage consisted mainly of Pseudomonas spp G. II (96-100%). The results were related to the saline composition of medium; however, Pseudomonas spp Gp. II were predominant with both media used.
Subject(s)
Crustacea/microbiology , Food Microbiology , Pseudomonas/isolation & purification , Shellfish , Animals , Argentina , Food Handling , Food Preservation , RefrigerationABSTRACT
A study was performed on the bacteriological, chemical and organoleptic characteristics of antartic krill (Euphausia superba) stored at 0-2 degrees C. After 6-8 hours of storage a dark color started in the head and legs and spread slowly to the tail. Within 24 hours 17
of the total nitrogen was lost by hepatopancreas autolisis. After 72 hours the krill became inedible due to strong amoniacal odor and flavor. These changes were associated with the multiplication of aerobic psychrophilic bacteria. The bacterial counts of freshly caught krill ranged between 3,7 X 10(2)/g and 2,5 X 10(5)/g at 21 degrees C. During storage at 0-2 degrees C the counts gradually increased and off-odors were produced when they reached values of 10(6)/g at 21 degrees C. The total volatile bases content of freshly caught krill, 0.018 to 0.038
, increased considerably during storage reaching values of approximately 0.100
when off-odors became noticeable and 0.200
or more when the odor was clearly ammoniacal. Pseudomonas spp Gp. II (Shewan) were predominant in the bacterial flora of the freshly caught krill along with Moraxella spp Alcalígenes spp, Vibrio spp, Micrococcus spp and coryneforms. The spoilage flora developed during cold storage consisted mainly of Pseudomonas spp G. II (96-100
). The results were related to the saline composition of medium; however, Pseudomonas spp Gp. II were predominant with both media used.
ABSTRACT
A study was performed on the bacteriological, chemical and organoleptic characteristics of antartic krill (Euphausia superba) stored at 0-2 degrees C. After 6-8 hours of storage a dark color started in the head and legs and spread slowly to the tail. Within 24 hours 17
of the total nitrogen was lost by hepatopancreas autolisis. After 72 hours the krill became inedible due to strong amoniacal odor and flavor. These changes were associated with the multiplication of aerobic psychrophilic bacteria. The bacterial counts of freshly caught krill ranged between 3,7 X 10(2)/g and 2,5 X 10(5)/g at 21 degrees C. During storage at 0-2 degrees C the counts gradually increased and off-odors were produced when they reached values of 10(6)/g at 21 degrees C. The total volatile bases content of freshly caught krill, 0.018 to 0.038
, increased considerably during storage reaching values of approximately 0.100
when off-odors became noticeable and 0.200
or more when the odor was clearly ammoniacal. Pseudomonas spp Gp. II (Shewan) were predominant in the bacterial flora of the freshly caught krill along with Moraxella spp Alcalígenes spp, Vibrio spp, Micrococcus spp and coryneforms. The spoilage flora developed during cold storage consisted mainly of Pseudomonas spp G. II (96-100
). The results were related to the saline composition of medium; however, Pseudomonas spp Gp. II were predominant with both media used.
ABSTRACT
Carbon blacks used in tire production have been examined for their polycyclic aromatic hydrocarbons (P.A.H.) content. The analytical procedures commonly adopted are discussed. The results obtained show that, A benzene extraction time of 250 hours is necessary to obtain complete extraction, but for practical purposes, an extraction time of 150 hours is sufficient to extract more than 95% of the PAH. It is possible to identify two classes of blacks in regard to extractables. The one class provides extractables in the range of 200--400 micrograms/g; the second class, in the range of 1000--2000 micrograms/g. No P.A.H. were detected by direct injection of carbon black into the mass spectrograph at 200 degrees C, 10(-6) torr. This was probably due to the very strong bonding to the black particles. The P.A.H. contribute a relative constant percentage of the benzene extracts. It is reasonably possible to exclude any carcinogenic risk to personnel, in a working environment, with an airborne carbon black concentration equal to or less than 3.5 mg/m3, due to the very low P.A.H. content of carbon black and to the very strong P.A.H. bonding to the black particles.
Subject(s)
Carbon/analysis , Carcinogens, Environmental/analysis , Polycyclic Compounds/analysis , Rubber , Industry , Mass Spectrometry , RiskSubject(s)
Adrenal Cortex Hormones/adverse effects , Air Pollutants, Occupational/adverse effects , Air Pollutants/adverse effects , Cushing Syndrome/chemically induced , Drug Industry , Occupational Diseases/chemically induced , Adult , Environmental Exposure , Female , Hormones/adverse effects , Humans , Male , Middle Aged , PowdersSubject(s)
Anthropometry , Ergonomics , Occupational Medicine , Humans , Italy , Male , Population DynamicsABSTRACT
Some improvements on a machine used in the steel cord industry are described. The main ergonomic problems found in a department with such machines are the high noise and heat. The noise produced by the machine and by its components was studied and an enclosure containing the most noisy parts was built. In order to reduce the heat released by the machine at the man's level ( approximately 2600 kcal/h) a system which carries the hot air up to 2.5 meters was studied. Such a system, which reduces by about 50% the heat released at the man's level, works by exploiting some of the energy absorbed by the machine itself.
