The benefits of applying the microscopic examination in the analysis of meat products

Abstract

The microscopic examination of meat products allows the identification of tissue structures and, to a certain extent, of the unauthorized content of plant and animal origin, the detection of parasites, the quality evaluation of the meat having undergone processes of freezing and thawing, the detection of muscle degeneration, the detection of foodstuffs adulteration and of the dangerous ingredients in meat products. The purpose of this study was to emphasise the importance of the results attained by microscopic evaluation of the integrity and quality of the meat used for meat products, the detection of the constituents of animal and vegetal origin, of the non-authorized tissues in the analysed products using routine staining as well as special staining. A total of 22 samples from different categories of meat products, represented by: boiled and smoked products (n = 5), cooked and double-smoked products (n = 2), raw-dried meat products (n = 6), baked and smoked meat products (n = 3), smoked meat products (n = 6), were randomly purchased from the commercial network within their validity period. All samples were processed using the routine paraffin inclusion technique, initially stained with HE (haematoxylin - eosin), special Masson's trichrome stain (connective tissue) and GMS II (Grocott Methenamine Silver, for the revealing of fungi). Microscopically, in the examined sections, there were highlighted different types of connective tissue (adipose and fibrous) in all of the samples, serous glandular tissue in baked and smoked meat products and in raw-dried meat products, visceral fragments (kidneys) in baked meat products and in raw-dried meat products, parasitic structures (Sarcocystis spp.) in baked and smoked meat products and in smoked meat products, fungal fragments in baked and smoked meat products and in smoked meat products, their presence being unauthorized. We consider that such an analysis, if appropriately performed and interpreted, can provide objective information in order to verify the compliance of these products with the legislation in force and to ensure the accurate composition and the integrity of these foods. By means of routine microscopic examination, the HE technique, non-compliant structures of animal origin were identified: visceral fragments and parasitic structures, Masson’s trichrome stain method allows a better highlighting of the connective tissue, and the GMS 2 technique can be used successfully for highlighting the fungal structures in meat products.