Detection of raw and heat-processed meat from cattle and poultry that died before slaughter

Meat and meat products are among the most frequently adulterated food items. Fraud involving the mixing of meats from different animal species can now be easily detected. However, meat illegally obtained from animals that died before slaughter (pre-slaughter dead animals, PSDAs) is often subjected to processes such as marination and seasoning to mask its poor quality, and is then illicitly introduced into the food supply. Since such meat has the same genetic structure as meat obtained under proper conditions, it cannot be distinguished by conventional methods. Consumption of this meat carries various risks, including the transmission of zoonotic diseases. According to Islamic dietary rules, the consumption of meat from PSDAs is considered haram (forbidden). At present, there is no method capable of detecting PSDA meat once it has been marinated or heat-treated, especially when it comes from the same animal species. This study aimed to investigate the potential use of sphingosine and cortisol levels, as well as the qualitative pseudoperoxidase test, in detecting PSDA beef and chicken meat whether raw, frozen, marinated, or cooked. In the study, PSDA beef and chicken samples were used as the experimental group, while meat from normally slaughtered animals (NSAs) was used as the control group. The samples were divided into two groups and stored at +4°C and -18°C for 24 hours. Ground beef was prepared from both PSDA and NSA samples and mixed with spices to produce raw Adana kebab mix (RAKM). Similarly, chicken samples from both groups were cubed, marinated for one hour, and used to prepare raw marinated chicken cubes (RMCC). Both RAKM and RMCC were cooked until the internal temperature reached 72°C, resulting in cooked Adana kebab (CAK) and cooked marinated chicken (CMC), respectively. At each processing stage, samples were collected, and sphingosine and cortisol levels were measured using ELISA. The pseudoperoxidase test was also applied. Total mesophilic aerobic colony count (TMACC), coliform count, and pH were determened at each stage, while salt content was analysed in processed and cooked samples. In chicken samples, no statistically significant difference in sphingosine levels was observed between the PSDA and NSA groups (P > 0.05). However, in beef samples, sphingosine levels in both ground and cooked Adana kebab (CAK) from the NSA-frozen (NSA-F) group were significantly higher than those in the PSDA-chilled (PSDA-C) group (P < 0.05). No statistically significant differences in cortisol levels were found among any of the beef or chicken groups (P > 0.05). In the pseudoperoxidase test, the reaction occurred significantly faster in PSDA beef samples compared to NSA samples (P < 0.05). All PSDA chicken samples produced a positive reaction, whereas none of the NSA chicken samples did (P < 0.05). Additional experiments conducted to determine the effect of cooking on the pseudoperoxidase reaction revealed that chicken meat subjected to 72°C, 90°C, and 121°C still produced a positive result. No statistically significant differences were found between PSDA and NSA groups in terms of TMACC, coliform count, salt, or pH values (P > 0.05). In conclusion, cortisol levels may not be a suitable parameter for distinguishing between PSDA and NSA meat from beef or chicken. However, analyzing sphingosine with a more sensitive method and larger sample size may yield promising results. On the other hand, the pseudoperoxidase test was found to be effective for distinguishing between PSDA and NSA meat samples for both beef and chicken, in raw and cooked forms, suggesting its potential use in meat inspections for detecting PSDA meat. Keywords: sphingosine, cortisol, pseudoperoxidase, dead animal meat, adulteration