Finding an abnormal sac-like structure in meat can be unsettling for consumers. These structures, commonly referred to as cysts, are formations that can appear in animal muscle tissue. This article explains what these cysts are, how to identify them, their biological origins, and what steps to take for safety and handling.
How to Identify a Cyst in Meat
Cysts in meat can vary in their visual and tactile characteristics. They commonly appear as round or oval lumps, ranging in size from a few millimeters to several centimeters in diameter. While some cysts may be firm or gritty to the touch, others can be fluid-filled, resembling a blister.
The color of these structures can also vary, often appearing white or yellowish, but sometimes they can be greenish if an infection is present. Distinguishing a cyst from normal meat components like fat, gristle, or lymph nodes is helpful. Lymph nodes, for instance, are gray or light-brown, marble-sized lumps found in fatty areas between muscles, and are a natural part of the animal.
Biological Origins of Cysts in Meat
Cysts in meat primarily stem from parasitic infections in livestock. Tapeworm larvae, such as Taenia saginata in beef and Taenia solium in pork, are frequent causes. When cattle ingest Taenia saginata eggs from contaminated pastures, the larvae migrate to muscle tissue, forming fluid-filled cysts, also known as “beef measles,” in areas like the heart, jaw, diaphragm, and tongue. Similarly, pigs can become infected with Taenia solium by ingesting eggs from contaminated feed or water, leading to cysts in their muscles. These parasitic cysts represent a resting stage for the parasite within the animal’s muscle tissue.
Sarcocystis, another protozoan, is found in the muscle tissue of domestic food animals like cattle and pigs. These parasites form cysts in the host’s muscles. Sarcocystis cysts can be microscopic or visible, appearing as milky white, opaque bodies between muscle bundles, and can be various shapes like fusiform or oval.
Beyond parasites, localized bacterial infections can also lead to abscesses, which are collections of pus surrounded by a fibrous wall. These abscesses can be creamy yellow or greenish and vary in size, forming anywhere in the animal’s body, frequently in skeletal muscles. Benign growths like lipomas (fatty tumors) or fibromas (fibrous tissue) can also be mistaken for cysts. These growths are harmless to the animal and do not spread.
Safety and Handling When Finding a Cyst
Discovering a cyst in meat can be concerning, but proper handling ensures the safety of the remaining product. If a cyst is found, the affected portion of the meat should be trimmed away and discarded. This localized removal is sufficient, as an isolated cyst does not contaminate the entire cut of meat.
The most important step for ensuring safety is thorough cooking of all meat. Heat effectively inactivates most parasites and bacteria that might be associated with such structures. For example, cooking whole cuts of pork to an internal temperature of 145°F (63°C) for 15 seconds, and whole pork roasts to 145°F (63°C) for at least three minutes, is recommended to eliminate potential pathogens. Ground meat, including ground pork, should reach 160°F (71°C).
If the affected area is widespread, or if the meat exhibits other signs of spoilage such as an unusual odor, sliminess, or significant discoloration (like gray, green, or brown hues beyond normal meat color), discard the entire product. While some bacteria are killed by cooking, certain bacterial toxins or mold toxins may remain heat-stable and dangerous. Isolated cysts are common occurrences in meat and do not pose a major health threat if handled correctly through trimming and proper cooking.