A. Priadi
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Effects of irradiation on the survival of bacterial contaminants in food Natalia, Lily; Priadi, A.; Irawati, Z.
Indonesian Journal of Animal and Veterinary Sciences Vol 14, No 1 (2009)
Publisher : Indonesian Animal Sciences Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (56.987 KB) | DOI: 10.14334/jitv.v14i1.364

Abstract

The primary concern about microbial safety of irradiated food is the survival of pathogenic spore forming bacteria. Clostridium sporogenes was selected as the spore forming test organism for conducting inoculated pack studies for its similarities to the most toxigenic Cl. botulinum, in radiation resistance. Minimum radiation dose applied (45 kGy under cryogenic condition, in -790C) was determined to eliminate Cl. sporogenes spores and other bacterial contaminants in different kind of Indonesian chicken and beef dishes. In separate studies, irradiation doses of 3 – 7 kGy at cryogenic condition was used to improve the microbiological safety of a number chilled prepared meals. The dishes or ready to eat foods were packaged in air impermeable pouches. Irradiation process was carried out after inoculation on chicken and beef dishes with certain amounts of Cl. sporogenes spores. The evaluation of colony count differences between the irradiated and unirradiated foods revealed the effect of radiation on the survival of bacterial spores or other bacterial contaminants. It was demonstrated that a minimum dose of 45 kGy under cryogenic condition eliminated the spore of Cl. sporogenes, Bacillus spp and Staphylococcus spp. Irradiation at doses 5-7 kGy significantly reduced some potential pathogenic microorganisms in samples without affecting quality up to 3 months of storage at the refrigeration temperature. Key Words: Food Safety, Irradiation, Bacterial Contaminants
Inactivation of Bacillus anthracis by Gamma irradiation Natalia, N.; Priadi, A.; Irawati, Z.
Indonesian Journal of Animal and Veterinary Sciences Vol 14, No 3 (2009)
Publisher : Indonesian Animal Sciences Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (289.628 KB) | DOI: 10.14334/jitv.v14i3.347

Abstract

The use of Bacillus anthracis as a biological weapon heighlightened awareness of the need for validated methods for the inactivation of B. anthracis spores. Ionizing radiation is capable of causing a variety of chemical changes and biological effects on bacteria which can be due both to direct interactions with critical cell components and to indirect actions on bacteria by molecular entities formed as a result of radiolysis of other molecules in the bacterial cell. This study determined the gamma irradiation dose for inactivating B. anthracis spores and its biological effects on the bacterial characteristics. Gamma irradiation was conducted at the IRKA irradiator at the National Nuclear Energy Agency, Jakarta and cobalt-60 was used as the source of ionizing radiation (capacity of ca. 134,044 Kci). Freeze dried culture of B. anthracis in glass ampoules was irradiated using   variable doses of 30, 20 and 10 KGy. Viability, biochemical and protease enzyme characteristics of B. anthracis were evaluated before and after irradiation.  The ability of B. anthracis to degrade gelatin, haemoglobin and bovine immunoglobulin G was also tested. The results showed that ionizing radiation  was able to inactivate or kill 11,05 x 108 cfu B. anthracis by 95.37%, 99.58% and 99.99 at respective doses of 10, 20 and 30 KGy. Bacterial spores appear to be less susceptible to irradiation than the vegetative cells, because of their specific structure. The survive spores irradiated at 30kGy shows some biochemical characteristic changes. The survivors failed to degrade methyl -D-glucopyranoside and arbutine. The ability of B. anthracis protease to degrade gelatin, haemoglobin and bovine immunoglobulin G was not affected by irradiation. These findings showed that a gamma irradiation at 30 KGy effectively inactivates B. anthracis spores without changing the protease activities. Key words: Gamma Irradiation, B. anthracis Characters, Protease
Effects of irradiation on the survival of bacterial contaminants in food Lily Natalia; A. Priadi; Z. Irawati
Jurnal Ilmu Ternak dan Veteriner Vol 14, No 1 (2009): MARCH 2009
Publisher : Indonesian Center for Animal Research and Development (ICARD)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (56.987 KB) | DOI: 10.14334/jitv.v14i1.364

Abstract

The primary concern about microbial safety of irradiated food is the survival of pathogenic spore forming bacteria. Clostridium sporogenes was selected as the spore forming test organism for conducting inoculated pack studies for its similarities to the most toxigenic Cl. botulinum, in radiation resistance. Minimum radiation dose applied (45 kGy under cryogenic condition, in -790C) was determined to eliminate Cl. sporogenes spores and other bacterial contaminants in different kind of Indonesian chicken and beef dishes. In separate studies, irradiation doses of 3 – 7 kGy at cryogenic condition was used to improve the microbiological safety of a number chilled prepared meals. The dishes or ready to eat foods were packaged in air impermeable pouches. Irradiation process was carried out after inoculation on chicken and beef dishes with certain amounts of Cl. sporogenes spores. The evaluation of colony count differences between the irradiated and unirradiated foods revealed the effect of radiation on the survival of bacterial spores or other bacterial contaminants. It was demonstrated that a minimum dose of 45 kGy under cryogenic condition eliminated the spore of Cl. sporogenes, Bacillus spp and Staphylococcus spp. Irradiation at doses 5-7 kGy significantly reduced some potential pathogenic microorganisms in samples without affecting quality up to 3 months of storage at the refrigeration temperature. Key Words: Food Safety, Irradiation, Bacterial Contaminants
Inactivation of Bacillus anthracis by Gamma irradiation N. Natalia; A. Priadi; Z. Irawati
Jurnal Ilmu Ternak dan Veteriner Vol 14, No 3 (2009): SEPTEMBER 2009
Publisher : Indonesian Center for Animal Research and Development (ICARD)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (289.628 KB) | DOI: 10.14334/jitv.v14i3.347

Abstract

The use of Bacillus anthracis as a biological weapon heighlightened awareness of the need for validated methods for the inactivation of B. anthracis spores. Ionizing radiation is capable of causing a variety of chemical changes and biological effects on bacteria which can be due both to direct interactions with critical cell components and to indirect actions on bacteria by molecular entities formed as a result of radiolysis of other molecules in the bacterial cell. This study determined the gamma irradiation dose for inactivating B. anthracis spores and its biological effects on the bacterial characteristics. Gamma irradiation was conducted at the IRKA irradiator at the National Nuclear Energy Agency, Jakarta and cobalt-60 was used as the source of ionizing radiation (capacity of ca. 134,044 Kci). Freeze dried culture of B. anthracis in glass ampoules was irradiated using   variable doses of 30, 20 and 10 KGy. Viability, biochemical and protease enzyme characteristics of B. anthracis were evaluated before and after irradiation.  The ability of B. anthracis to degrade gelatin, haemoglobin and bovine immunoglobulin G was also tested. The results showed that ionizing radiation  was able to inactivate or kill 11,05 x 108 cfu B. anthracis by 95.37%, 99.58% and 99.99 at respective doses of 10, 20 and 30 KGy. Bacterial spores appear to be less susceptible to irradiation than the vegetative cells, because of their specific structure. The survive spores irradiated at 30kGy shows some biochemical characteristic changes. The survivors failed to degrade methyl -D-glucopyranoside and arbutine. The ability of B. anthracis protease to degrade gelatin, haemoglobin and bovine immunoglobulin G was not affected by irradiation. These findings showed that a gamma irradiation at 30 KGy effectively inactivates B. anthracis spores without changing the protease activities. Key words: Gamma Irradiation, B. anthracis Characters, Protease