Salmonella in horses at slaughter and public health effects in Italy

The study assessed the role of equids at slaughter as faecal carriers of Salmonella enterica and the occurrence of contaminated equid carcasses during the slaughter process in Northern Italy (Emilia-Romagna Region). From June to November 2021, 152 equids (146 horses, 5 donkeys and 1 mule) were tested for Salmonella both in caecal contents and through carcass swabs. Antimicrobial resistance (AMR) of recovered strains was tested against 15 antimicrobials. Salmonella was detected in 3/152 of the caecal contents (2.0 %), while all carcass samples were negative. S. enterica serovars Enteriditis, Typhimurium and Stanleyville were identified. The only AMR isolate was S. Typhimurium with AMR profile AmCStxT. Considering the consumption of raw horse meat (i.e., minced raw meat named "pesto di cavallo" and dried and smoked strips named "sfilacci di cavallo") in different areas of Northern Italy, we also investigated the possible link between horse meat eating and salmonellosis cases in the human population in the same area. Specifically, we compared the Salmonella strains collected during the study with those routinely processed in the laboratory surveillance system for human salmonellosis in Emilia-Romagna (a region with about 4.5 million inhabitants). The comparison was based on whole genome sequencing data through core genome multi-locus sequence typing (cgMLST) used in routine surveillance. A genomic match in cgMLST was found between the strain of S. enterica serovar Enteritidis isolated from a horse caecal content and an enduring outbreak of 17 human cases in Emilia-Romagna during the study period. The consequent epidemiological investigation highlighted that a number of cases with known food history reported the consumption of horse meat and traced different batches of the consumed meat, released weeks apart from each other, to the slaughter investigated in the study. The results of the epidemiological investigation suggested the role of horses in the S. enterica serovar Enteritidis outbreak affecting raw horse meat consumers. This study shows that, despite the low prevalence on equid carcasses, S. enterica in horse meat can represent a risk to consumers. From the perspective of the slaughter activities, this highlights the need to maintain a high level of hygiene during the entire process, starting from the hygiene at lairage up to the slaughtering phase and dressing of carcasses.

Sarcocystis in horses from Rio Grande do Sul, Brazil: Molecular identification of Sarcocystis bertrami and Sarcocystis neurona in muscle tissues

Horses are intermediate hosts of Sarcocystis spp. capable of forming cysts in their musculature. This study aimed to detect sarcocysts and investigate the presence of nucleic acids from Sarcocystis spp. in samples of striated muscles from horses in the State of Rio Grande do Sul, Brazil, necropsied at the Veterinary Pathology Laboratory of the Federal University of Santa Maria. A total of 108 samples were collected from 24 horses and examined through direct examination. Microscopic tissue cysts were observed in three samples: tongue (2) and esophagus (1) from two animals. Extractions were performed on the found cysts and tissues, even though sarcocystosis detection was not present. DNA samples were subjected to Nested-PCR using Tg18s primers, and the amplified products were subjected to Restriction Fragment Length Polymorphism (RFLP) using DdeI and HpaII enzymes. DNA belonging to Sarcocystis spp. was amplified in tissues from 91.7% (22/24) of the equines, and 67.6% (73/108) of the samples tested positive in the Nested-PCR reaction. The tissues with the highest detection frequency were: diaphragm 92.3% (12/13), gluteal muscle 77.2% (17/22), and esophagus 66.7% (4/6). In RFLP, Sarcocystis spp. was detected in 21 tissues from 11/22 equines, and cysts, identified through nucleotide sequencing, were determined to be S. bertrami. S. neurona was identified in 11 samples from 7/22 animals, with co-infection detected in 5/22 cases. The high detection rate indicates a concerning circulation of the protozoan, particularly the zoonotic S. bertrami found in all tissues, which are commonly exported for human consumption.

Horsemeat consumption in France: Determinants and sustainable market perspectives

In France, the horsemeat market has been declining for about 50 years and has become a specialized market. Our study aims to understand this decline with regard to the drivers and practices of consumers and non-consumers of this meat, in order to estimate the potential for this market development. To study horsemeat consumption, we analyze two sets of data: two large-scale surveys carried out on the French general population, and one ad-hoc survey focusing more specifically on the representations of horses and horsemeat. Our results underline the potential for increasing horsemeat consumption from a sustainability perspective. The question of moral acceptance remains a determining factor in the consumption of this meat. Once this factor is taken into account, horsemeat appears relevant in the diversification of animal protein consumption because of its particular nutritional and environmental properties and similar culinary use to that of other red meats. Horsemeat can thus lay claim to becoming a sustainable alternative to beef consumption.

Characterization of a new bacteriocin-like inhibitory peptide produced by Lactobacillus sakei B-RKM 0559

The biopreservation strategy allows extending the shelf life and food safety through the use of indigenous or controlled microbiota and their antimicrobial compounds. The aim of this work was to characterize an inhibitory substance with bacteriocin-like activity (Sak-59) produced by the potentially probiotic L. sakei strain from artisanal traditional Kazakh horse meat product Kazy. The maximum production of Sak-59 occurred at the stationary phase of the L. sakei growth. Sak-59 showed inhibitory activity against gram-positive meat spoilage bacteria strains of Listeria monocytogenes, Staphylococcus aureus, and pathogenic gram-negative bacteria strains of Serratia marcescens and Escherichia coli, but not against the tested Lactobacilli strains. Sak-59 activity, as measured by diffusion assay in agar wells, was completely suppressed after treatment with proteolytic enzymes and remained stable after treatment with α-amylase and lipase, indicating that Sak-59 is a peptide and most likely not glycosylated or lipidated. It was concluded that Sak-59 is a potential new bacteriocin with a characteristic activity spectrum, which can be useful in the food and feed industries.

Effect of three different proteases on horsemeat tenderness during postmortem aging

In this study, the semitendinosus of horse meat was used as the raw material. The study assessed the variation of the tenderness of horse meat during postmortem aging through the injection of papain, bromelain and fungal protease. The cooking loss of the horse meat became worse during postmortem aging. Low concentration of protease improved water retention properties of horse meat. Papain, bromelain and fungal protease had significant influence on MFI and shear force. MFI increased obviously but the shear force decreased significantly with the addition of more protease (p <0.05). During postmortem aging, many small molecules popeptide appeared in treatment group. Myosin light chain 2, 20 KDa, 32 KDa and 75 KDa bands appeared at first, however later they disappeared in the group with high concentration of protease treatment in addition to the disappearance of Desmin and Troponin I. The muscle fiber, perimysium and endomysium were degraded because of papain, bromelain and fungal protease treatment. More muscle fiber fragments appeared during postmortem aging.Thus, the tenderness and eating quality of horse meat were improved by adding three kinds of protease.

Effect of ageing time on consumer preference and sensory description of foal meat

A consumer test (n = 120) was performed in Vitoria-Gasteiz (northern Spain) in order to study the effect of ageing time (0, 7, 14 and 21 days) on the sensory quality of Hispano-Bretón foal meat. Steaks (Longissimus thoracis et lumborum) were wet aged and evaluated in-mouth and visually. In both cases, acceptability was scored using a hedonic scale, and sensory drivers related to ageing were characterised by applying check-all-that-apply method in meat. For both, in-mouth and visual acceptability, meat aged for 7 days obtained higher scores than non-aged meat, whereas longer ageing periods did not improve consumer acceptability. Check-all-that-apply method showed to be able to discriminate among samples, both in-mouth and visually. Results revealed that texture related attributes were the most discriminant ones in the in-mouth evaluation, being non-aged meat related to 'dry', 'high residue', 'tough' and 'chewy' terms, whereas aged meat was associated to 'juicy', 'tender' and 'easily dissolving' terms. Visually, consumers perceived that, after 14 days of ageing, meat colour changed to 'brownish'. Under present study conditions, the establishment of a period of 7 days of ageing would be recommended.

Application of proteomic to investigate the post-mortem tenderization rate of different horse muscles

The aim of this study was to evaluate the effect of post-mortem aging on tenderness development and proteolysis of myofibrillar proteins in 3 different horse muscles. Warner-Bratzler shear force decreased during aging in all muscles, showing the lowest values in longissimus lumborum (LL) in all sampling points. Myofibril fragmentation index significantly increased in LL and semimembranosus (SM) muscles throughout aging time whereas in semitendinosus (ST) it increased after 14 days of aging. Proteomics analysis revealed the major content of intact myofibrillar proteins with high molecular weight in ST muscle in the first phase of aging, while, after 14 days a higher accumulation of TnT-derived polypeptides and spots isoforms ascribed to MLC2 and MLC1 proteins were found. Data highlight that aging affects the meat tenderness and proteolysis with different intensities in each muscle and suggest that a more extensive post-mortem proteolysis occurred in ST muscle.

Investigation of phenylbutazone and its metabolite oxyphenbutazone in horse meat products during years 2013-2017

This study showed the results of a monitoring program aimed at detecting the fraudulent use of horse meat in samples collected in the framework of official controls during the years 2013-2017 after the so-called horse meat scandal that caused a decreasing consumer confidence in the food industry, particularly in meat products. A total of 125 samples diversely distributed in the 5 years of monitoring were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated according to Commission Decision 657/2002/EC with regard to the following parameters: linearity, specificity, decision limit (CCα), detection capability (CCβ), recovery, and precision (repeatability and within-laboratory reproducibility). Even if the results of this study revealed no positive sample, the need for constant assurance of food safety and consumers' health protection requires the implementation of preventive as well as corrective actions in the management of risks linked to the food chain in a more global context.

Evaluation of the PrioCHECK™ Trichinella AAD Kit for the digestion and recovery of larvae in pork, horse meat and wild meat

The artificial digestion magnetic stirrer method using pepsin protease and hydrochloric acid is the standard assay for the detection of Trichinella larvae in muscle of infected animals. Recently, an alternative enzyme, serine protease, was employed in the development of a commercially available digestion kit (PrioCHECK™ Trichinella AAD Kit). This assay requires a higher digestion temperature of 60°C which kills the larvae during the digestion process, mitigating the risk of environmental contamination from the parasite. The present study was conducted to determine the performance of the PrioCHECK™ Trichinella AAD Kit compared to the conventional pepsin/HCl digestion. Replicate paired 115g samples of Trichinella-negative pork diaphragm and masseter, and of horse tongue and masseter, were used to compare the two methods for tissue digestibility. Similarly, paired 100g samples of pork diaphragm and horse tongue were spiked with proficiency samples containing known numbers of Trichinella spiralis first stage larvae to compare larval recoveries for the two methods. Masseter samples from wild bears and wolves naturally infected with Trichinella nativa or T6 were also used to compare the performance of the methods. The results of the study showed that the PrioCHECK™ Trichinella AAD Kit, when used according to the manufacturer's instructions, was effective in detecting Trichinella infection in all samples that contained 0.05 or more larvae per gram of tissue. Although there was no significant difference between the Kit method and the standard pepsin/HCl digestion procedure in the average number of larvae recovered from spiked pork diaphragm, 38% fewer larvae were recovered from similarly spiked samples of horse tongue by digestion using serine protease (one way ANOVA, P value <0.001). Additional clarification was also more often required for both horse meat and pork when using the Kit compared to the pepsin/HCl method. The results of testing wildlife samples were similar for the two methods. Overall, the performance of the Kit method was suitable for the digestion of muscle samples and recovery of Trichinella larvae, according to international standards. It also provides advantages of faster digestion, safer reagents and recovered parasites that are non-hazardous for analysts and the environment.

Proficiency testing to detect Trichinella larvae in meat in the European Union

According to the Commission Implementing Regulation (EU) 2015/1375 (replacing the Commission Regulation (EC) No 2075/2005), all animals, which are potential carriers of Trichinella spp. larvae, should be tested at the slaughterhouse or game-handling establishments according to one of the approved tests. One of the core duties of the European Union Reference Laboratory for Parasites is to organize proficiency testing (PT), as stated in the Commission Regulation (EC) No. 882/2004 of the European Parliament and of the Council. The aim of this work was to evaluate the results of PTs of the digestion method carried out by the National Reference Laboratories for Parasites (NRLPs) over a nine year period (2007-2015). Participating laboratories received a panel of samples consisting in 35g or 100g of minced pork or horse meat spiked with Trichinella spiralis live larvae. The number of spiked samples varied from 2 to 9 over the years. A negative control was also included in the panel, except during the 2015 PT, when only positive samples were used. The percentage of NRLPs, which passed the PT, increased from 83.3% in 2007 to 100% in 2014. Considering the number of recovered larvae, the heterogeneity in participant's results reduced overtime. The values of the overall mean difference between spiked and recovered larvae decreased during the study period, witnessing a general improvement of NRLPs performance and confirming the effectiveness of PT for a good performance of this test.