## 4 Conclusions  
The characterization of anti-MG monoclonal antibodies and their conjugates with biotin and AuNPs were carried out by the ELISA and LFIA. An optimal pair of immunoreagents was selected, for detecting MG in the sandwich-format LFIA with a sensitivity of 5 ng/mL within 15 min. The test system specifically detects MG isolated from pork and demonstrates no cross-reactivity with MG of other species of mammals and birds. A simple and rapid technique for sample preparation is proposed that efficiently extracts MG from raw and cooked meat products. The developed LFIA can detect quantities of pork additives, as low as 0.01%, in beef. The assay results can be monitored visually or  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Method** & **Analyte** & **Detection Limit, \%** & **Extraction Time, min** & **Time of Analysis, min** & **Reference** \\ \hline ELISA & IgG & 0.01/0.1 & \textgreater{}40 & \textgreater{}70045 & [8] \\ Immunonsensor & IgG & 0.01 & \textgreater{}40 & 20 & [8] \\ PCR & DNA & 5 & 235 & 80 & [9] \\ Real-time PCR & DNA & 0.1 & 235 & 28 & [9] \\ UPLC & Proteins profile & 5 & 40 & 30 & [23] \\ LFIA & DNA & 0.02 & \textgreater{}60 & 15 & [11] \\ LFIA & DNA & 0.01 & \textgreater{}90 & 5 & [12] \\ LFIA & PSA\({}^{\star}\) & 0.01 & 25 & 15 & [16] \\ LFIA & IgG & 0.1 & 65 & 15 & [18] \\ LFIA & MG & 0.01 & 20 & 15 & Present work \\ \hline \hline \end{tabular} PSA\({}^{\star}\), pig serum albumin.  
\end{table}
Table 4: Comparison of methods for porcine meat detection.  
Figure 6: Images of test strips after the LFIA. (**1**) Beef/pork cooked sausages (**2**) Beef/pork cooked and smoked sausages; (**3**) Beef/pork dumplings; (**4**) Vension/pork dumplings; (**5**) Beef dumplings; (**6**) Lamb dumplings; (**7**) Chicken dumplings.  
using a photometric detector (scanner). The proposed test system is able to detect pork MG in food products that have passed all stages of the technological cycle.  
The advantage of the developed test system over the existing approaches for porcine meat detection is the reduction in the assay duration (sample preparation + the LFIA step). This feature, and low demands for the common equipment used, determines the competitive potential of the given developments. Due to the rapidity and methodological simplicity, the proposed assay can be considered to be an efficient screening tool for identifying undeclared additives of porcine meat in meat products.  
Conceptualization, E.A.Z., A.V.Z., and B.B.D.; Methodology, E.A.Z.; Software, D.S.P.; Validation, O.D.H.; Formal analysis, N.A.B. and O.D.H.; Investigation, E.A.Z., N.A.B., K.A.B., and O.D.H.; Resources, A.V.Z.; Writing--original draft preparation, E.A.Z.; Writing--review and editing, A.V.Z.; Visualization, D.S.P.; Project administration, B.B.D.; Funding acquisition, A.V.Z. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Russian Science Foundation (project no. 19-16-00108).  
The authors are grateful to Academician [PERSON] and [PERSON] (V.M. Gorbatov Federal Research Center for Food Systems) for preparation and providing cooked meat products of known composition, to [PERSON] (Russian Research Center of Molecular Diagnostics and Therapy) for providing monoclonal antibodies against MG, and to [PERSON] (Research Center of Biotechnology) for supplying and processing TEM microphotographs.  
The authors declare no conflict of interest.