Comparison of Meat Juice Serology and Bacteriology for Surveillance of Salmonella in the Brazilian Pork Production Chain

Abstract

This study assessed an ELISA based assay to detect Salmonella in swine as a potential tool to predict the presence of Salmonella in swine carcasses. Also, the research evaluated if meat juice can be used as an alternative to blood serum as a matrix for ELISA. The following samples were collected from ten batches of swine: blood (n = 100); environment (barn floor, n = 10, and lairage floor, n = 10); meat juice (n = 100, obtained after defrosting of diaphragm); tonsils (n = 100); mesenteric lymph nodes (n = 100); and carcasses after bleeding (n = 100), after singeing (n = 100), after evisceration (n = 100), and after final rinsing (n = 100). Blood and meat juice were subjected to ELISA to detect antibodies against Salmonella, and other samples were subjected to Salmonella detection by ISO 6579. Salmonella was detected in 3 samples from barn floors, 7 lairage floors, 45 tonsils, 43 mesenteric lymph nodes and in 3 carcasses. Based on ELISA, Salmonella positive samples were: 86 and 46 blood serum (20% and 40% cut-offs) and 68 and 46 meat juice (20% and 40% cut-offs). Optical density (OD) readings from blood serum and meat juice presented a high and significant correlation (r = 0.93, P < 0.001), and a substantial agreement for Salmonella detection (K = 0.69, ELISA 40% cut-off). ELISA and microbiological detection presented an absence or poor agreement for Salmonella detection from different samples of the same pig carcass, with the exception of results obtained by ELISA 40% cut-off from blood serum and meat juice with mesenteric lymph nodes (K = 0.49 and 0.50, respectively) and tonsils (K = 0.29 and 0.30, respectively).Meat juice can be considered an alternative to blood serum as a matrix for ELISA in order to allow preliminary detection of Salmonella in mesenteric lymph nodes and tonsils, allowing the identification of potential sources of contamination during slaughtering.

Relevance of Meat Juice Seroprevalence and Presence of Yersinia enterocolitica and Salmonella spp. in Pig Tonsils for Risk Management at Slaughter

“…The seroprevalence of Salmonella spp. in the studied pig population was about 50%, with a slightly higher seroprevalence in small farms, which is consistent with the studies conducted [39,40]. Overall, more than 60% of the sampled farms were seropositive for Salmonella spp., which was expected given similar studies [3,41].…”

Systematic Review and Modelling of Age-Dependent Prevalence of Toxoplasma gondii in Livestock, Wildlife and Felids in Europe

“…Thirteen studies provided data on T. gondii detection using meat/muscle juice; however, sera of the same animals were never tested in parallel. Even though meat juice can be considered an alternative matrix to serum for antibody detection [ 47 ], performing indirect tests using serum samples appears to provide more reliable results than other matrices such as meat juice, where the concentration of the specific antibodies is less homogenous and depends on the muscle the meat juice has been extracted from [ 48 ]. Due to the lack of parallel testing of the two matrices, we cannot exclude the possibility of selection bias (i.e., meat juice has been used more often in populations with a higher risk of T. gondii infections) and consider blood serum as a matrix of choice for the specific anti- T. gondii antibody detection, despite the modelled outcome.…”

CRISPR Cas12a‐based “sweet” biosensor coupled with personal glucose meter readout for the point‐of‐care testing of Salmonella

“…Compared with other existing detection methods (Heymans et al., 2018; Nair et al., 2019; Qin et al., 2020; Sannigrahi et al., 2020; Viana et al., 2020; Vinayaka et al., 2019; Wu et al., 2021) (shown in Tables S4 and S5), the PGMs‐CRISPR assay exhibited a comparative or better sensitivity than golden‐standard methods in foodborne bacteria detection or other novel assays, such as culture‐based assays, immunomagnetic beads separation assays, and RT‐PCR. More importantly, our assay shows outstanding advantages in detection cost since no professional equipment was needed in the whole detection process, and a commercial PGM can provide any untrained users with the detection results.…”