## 4 Conclusions  
Thermal imaging cameras and FT-IR spectrophotometry can be used to assess the microbiological quality of food of animal origin. Microbiologically contaminated meat was shown to have a significantly higher surface temperature. Based on this, it was concluded that this method can quickly estimate the microbiological quality of poultry meat. It is therefore suggested that thermography may be useful for assessing the hygiene of the slaughter process and the suitability of poultry meat for processing.  
The technology has the advantage of being non-invasive and not burdened with the costs and time consumed by classical methods of assessing microbiological quality. The high purchase costs of a thermal imaging camera are one-time and quickly amortize in relation to the costs of microbiological analyses performed for many samples. Infrared thermography enables recording of dynamic distributions of radiation temperature of large surfaces, and therefore, many samples simultaneously. Of course, like any method, it has certain limitations that require improvement. Problems related to emissivity or heat losses resulting in apparent contrasts can be eliminated by validating this method directly on the production line. It was assumed that the thermal imaging measurement on the technological line would be performed in relation to a reference sample (meeting the criteria of microbiological quality), which is characterized by a specific spectrum. The measuring device can be programmed to read a spectral drawing typical of a good quality product (reference). If an incorrect spectrum is detected, a warning signal is obtained on the analyzer display, and the quality is verified using standard methods. In this way, false positive or negative results will be eliminated. Significant correlations were found between the indications of spectral (FT-IR) measurements and changes in microbiological and chemical quality in samples of stored poultry meat. Discriminant analyses provide an opportunity to develop an analytical model to rapidly eliminate samples that do not meet essential microbiological safety criteria, so there is great potential to apply this method directly to the production line. FT-IR can detect microbial contamination in the food industry, assuming a specific spectrum characterizes the uncontaminated raw material. The measurement device can be programmed to read the spectral drawing typical of the raw material. If an abnormal spectrum is detected, a warning signal is obtained on the analyzer's display.  
Conceptualization, E.L.; methodology, E.L. and P.K.; formal analysis, E.L., K.P. ([PERSON]), K.P. ([PERSON]) and P.K.; investigation, E.L.; data curation, E.L.; writing--original draft preparation, E.L., K.P. ([PERSON]), P.K. and S.B.; writing--review and editing, E.L. and K.P. ([PERSON]); visualization, E.L.; supervision, E.L.; project administration, E.L. All authors have read and agreed to the published version of the manuscript.  
Research equipment was purchased as part of the \"Food and Nutrition Centre--modernization of the WULS campus to create a Food and Nutrition Research and Development Centre (CZiZ)\" project co-financed by the European Union from the European Regional Development Fund under the Regional Operational Programme of the Mazowieckie Voivodeship for 2014-2020 (Project No. RPMA.01.01.00-14-8276/17).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Requests for the original contributions can be directed to the corresponding authors.  
**Acknowledgments:** The authors thank [PERSON] for their assistance with the experimental work conducted during their master's thesis.  
**Conflicts of Interest:** The authors declare no conflicts of interest.