Morphological analysis of pork assessment
Authors:   St. Petersburg State Academy of Veterinary Medicine, Smirnov A. , Urban V. ,   St. Petersburg State Academy of Veterinary Medicine
Published: November 2020

The article presents a morphological analysis of different thermal conditions of pork at the cellular level. The purpose of the study is to develop and improve classical histological techniques and methods for as-sessing the quality of raw meat to determine falsification. And to creat scientifically based methodology of scientific and practi-cal value. The objects of research were raw meat materials - pork with different thermal conditions: chilled, frozen, thawed. As a control, we used histological preparations of fresh pork meat, made by the classical meth-od according to GOST 19496-2013. The studies were carried out in accordance with the classical microstructural analysis and with standardized methods, in the author's modification. The author’s modification of the method allowed to reduce the time for preparing sections for research and to exclude expen-sive equipment for the preparation of histo-logical sections. Microscopy of sections was carried out using a MicroOptix MX 300 (T) light microscope (West Medica, Austria). Photography of the preparations was carried out using a CAM® V1200 (C) HD video camera (West Medica, Austria). The microstructure of meat undergoes changes in the process of autolysis. Micro-scopic analysis clearly reveals the general structural features of the studied muscles of chilled and thawed meat, as well as differ-ences in their internal structure. The thick-ness of the muscle fibers of different mus-cles is various. The corrugated or folded shape of many muscle fibers of the cooled meat is clearly visible in all muscles on the longitudinal section. Corrugated fibers have a slight contraction or are completely loose, and at the same time the adjacent straight fibers are strongly reduced. They cause fold-ing in neighboring relaxed fibers. It was found that corrugation and folding are unstable, they almost completely disap-pears in chilled meat. This is one of the mor-phological features that can be well observed with a magnification of 10 × 40 microscope and can be evaluate the quality of meat by the degree of maturation: fresh or chilled. The obtained data indicate that the gen-eral appearance of muscle fibers noticeably changes during freezing - the transverse striation can appear worse, undetected and sometimes it can disappears. All fibers be-come thinner after freezing. Significant changes occur in the nuclei of cells. In thawed meat, they become smaller and thinner, chromatin is visible as a contin-uous mass with a pycnotic nature. Chromatin coagulates into a continuous, highly stained mass. The nuclei change their shape and they can be looked like a dark elongated oval shape of a homogeneous mass. The use of histological and microscopic methods for studying comparative changes in fresh, chilled and thawed meat can con-tribute to the accuracy and improvement of methods for detecting thawed meat that can be used during falsification of chilled meat, as well as it allows to study processing and storage conditions for chilled meat.