Slaughterhouse Dispositions for Cysticercosis and Tuberculosis Lesions
At a municipal slaughterhouse, 20 buffalo carcasses are inspected after overnight chilling. Carcass 7 has multiple 5-10 mm pearly, fluid-filled cysts in the masseter, tongue, heart, and diaphragm; the cysts are numerous in all four sites. Carcass 12 has three firm, yellow, caseous nodules 2-3 cm in the lungs and bronchial lymph nodes; no lesions are found in the liver, spleen, mesenteric nodes, or other lymph nodes. Carcass 15 has one 6 mm cyst in the heart muscle only. The slaughterhouse has a cold room that can hold meat at -10 C, a clean cutting room, and a boiler. The meat inspector must decide on disposition and record the findings. Two workers handle the carcasses without gloves and one has a chronic cough.
1. Identify the lesions in carcasses 7, 12, and 15 and give a disposition for each, with reasons.
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Carcass 7 has heavy cysticercosis, consistent with Cysticercus bovis, with numerous cysts in the masseter, tongue, heart, and diaphragm. Heavy or generalised cysticercosis warrants condemnation of the whole carcass because chilling or cooking cannot be guaranteed to reach every cyst and the risk of human taeniasis is high. Carcass 15 has a single cardiac cyst, a light infection. The heart should be condemned, and the rest of the carcass may be passed only after an approved cold treatment or thorough cooking; a typical schedule is freezing at -10 C or below for at least 10 days, but the current local meat hygiene schedule must be followed and verified. Carcass 12 has caseous nodules in the lungs and bronchial lymph nodes consistent with localised tuberculosis. If examination of all other organs and lymph nodes is negative and the carcass is not emaciated, condemn the lungs and affected lymph nodes and pass the remainder. If lesions are found in both thoracic and abdominal lymph nodes or in multiple organs, treat as generalised tuberculosis and condemn the whole carcass.
2. What public health and occupational actions follow, and what would you do about the worker with chronic cough?
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Record the lesions, the carcass numbers, and the disposition in the inspection register, and retain or condemn the affected material so it cannot enter the food chain. Clean and disinfect the inspection area, knives, hooks, and tables. The workers handling carcasses without gloves must be instructed to use gloves, cover cuts, and wash hands; they should not eat, drink, or smoke in the slaughter area. Because tuberculosis and cysticercosis are both occupational and food-borne concerns, arrange health education for all workers. The worker with chronic cough should be referred for medical assessment, including chest X-ray and sputum examination for tuberculosis, rather than being assumed to have bovine tuberculosis. Advise the slaughterhouse owner to provide protective equipment and hand-washing facilities. If the coughing worker has active tuberculosis, he should not continue handling meat until medically cleared, and public health authorities should be informed according to local rules.
3. The slaughterhouse owner argues that freezing makes all three carcasses safe. Evaluate that claim.
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The claim is partly true for cysticercosis and false for tuberculosis. Freezing can kill Cysticercus bovis in lightly infected muscle if the approved time and temperature schedule is met, so carcass 15 can potentially be treated rather than condemned. But carcass 7 has heavy, multi-site infection, and the inspector should not rely on freezing to make a heavily infected carcass safe; it should be condemned. Freezing does not reliably destroy Mycobacterium bovis in tissues, so carcass 12 cannot be made safe by cold treatment. The affected lungs and lymph nodes must be condemned, and the rest of the carcass may be passed only if the examination shows no generalised lesions. The owner's argument confuses a parasite-killing process with a bacterial inactivation process. The inspector should explain the difference, record the decision, and ensure that any treated meat is clearly identified and kept under official control until the cold treatment is complete.