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| Author(s): |
Bruna Farias Alves
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2017-07-21 |
| Examining board members: |
Solange Maria Gennari;
Carlos Adam Conte Junior;
Herbert Sousa Soares
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| Advisor: | Solange Maria Gennari |
| Abstract | |
The objective of the present study was to evaluate the viability of Toxoplasma gondii cysts in pork processed by dry-aged for 14, 21 and 28 days at 0º (± 1), as well as to evaluate the distribution of T. gondii cysts in organs and commercial cuts of experimentally infected pigs. For that, two experiments were conducted ans in both the pigs were infected with 3.000 oocysts of the isolate TgCkBr57 (BrII). The loin was the muscle chosen to undergo the dry-aged because it is the cut conventionally used for the process. The right loin of each pig was submitted to the dry-aged and the left was kept as control, without processing. In Experiment 1, three pigs were infected. From the loins processed by dry-aged (n=3) e controle (n=3), the bioassay was performed on cats and mice and the aged period of the loins was 14 days. This study, also avaluated the distribution of T. gondii tissue cysts by bioassay in mice of brain, retina, tongue, diaphragm and hear and of the muscles: loin (m. longissimus), coppa (m. longissimus, spinalis dorsi, rhomboideus), tender loin (m. psoas major), outside flat (m. biceps femoris), topside (m. semimembranosus) and top sirloin (m. gluteos medius) was evaluated. In Experiment 2, six pigs were infected and the bioassay was performed in mice of the loins aged for 14 (n=2), 21 (n=2) and 28 (n=2) days. In both experiments, T. gondii cysts of the loins remained viable after 14 days of dry-aged, confirmed by bioassay in cats and mice. At 21 and 28 days, the bioassay showed that the mice did not become infected, indicating that the process made the cysts unfeasible. As to the distribution of the cysts, T. gondii was isolated from the coppa, heart, diaphragm and tongue of the three pigs, to the tender loin, outside flat and brain of two pigs and to the top sirloin and loin of one pig. No mice were infected in the bioassay with the topside and with the retina. The results demonstrate that the dry-aged for 14 days at controlled temperature (0ºC) was not effective for inactivation of T. gondii cysts, however, the process was efficient when the dry-aged was done for a period egual or righter than 21 days. Toxoplasma gondii cysts were found in practically all organs and cuts evaluated, demonstrating the wide distribution of the parasite in pigs and the importance of this species as a source of infection for man. (AU) | |
| FAPESP's process: | 15/20649-7 - Viability of Toxoplasma gondii cysts in pork processed by ageing from experimentally infected animals |
| Grantee: | Bruna Farias Alves |
| Support Opportunities: | Scholarships in Brazil - Master |