This study aimed to compare the oxidative stability of chicken breast and thigh meat from four distinct production systems differing in their level of intensification using an accelerated oxidation display model. The systems differed in housing conditions and growth rate of the genotypes: indoor and fast-growing (Ind_Fast), indoor and fast-medium-growing (Ind_Fastmed), outdoor and medium-growing (Out_Med), and outdoor and slow-growing (Out_Slow). Sixty mixed-sex broilers were randomly selected from 20 farms in Belgium (5 farms per production system × 3 chickens per farm). On day 2 post-slaughter, skinless breast and thigh meat from each chicken were ground separately. Forty g of ground sample was stored under light (1,600–2,200 lux, 2–4°C) for 168 h, while the remaining ground meat was used for composition analyses. Color CIE L* a* b* coordinates were measured at 0, 48, 96 and 168 h, with total color change (ΔE) calculated at the end of the display period. Lipid oxidation (thiobarbituric acid reactive substances, TBARS), and protein oxidation (protein carbonyl compounds, PCC) were measured at the end of display. In both breast and thigh, indoor-raised chickens exhibited lighter color, characterized by higher L*, and lower a* and b* (P < 0.001) compared to outdoor-raised chickens. However, outdoor-raised chickens showed greater ΔE compared to indoor counterparts, indicating lower color stability. TBARS were higher in breast meat from Out_Slow than Ind_Fast chickens (P < 0.05), whereas there were no significant differences between production systems in thigh meat. The TBARS values remained below the 1 mg/kg threshold for off-flavors in both meat cuts. PCC was not affected by production system in either meat cut. These differences in oxidative stability may be due to production system-related variation in fatty acid composition, heme iron concentration, and antioxidant status, with effects depending on the meat cut. The findings suggest that the observed variation in oxidative stability reflects the combined influence of multiple production system characteristics rather than the effect of any single factor.

This study evaluated the impact of dietary supplementation with antioxidants (AO) and flavouring prototypes based on capsicum (CA), acorn (AC), and olive (OL) on the volatile profile of pork. Two trials were conducted. Trial 1 served as a preliminary screening to evaluate samples of longissimus thoracis et lumborum (LTL) of 32 barrows fed with diets containing different levels of CA, AC, and OL. Results showed that dietary treatments significantly affected the abundance of seven volatile compounds, particularly long-chain aldehydes, while the fatty acid profile remained unaffected. Trial 2 consisted of a 2 × 3 × 2 factorial design evaluating AO supplementation (with and without AO), dietary flavouring prototypes (without, AC, and AC + OL), and sex (gilts vs. barrows), where LTL samples from 36 barrows and 36 gilts were evaluated. A total of 59 volatile compounds were identified. AC supplementation resulted in significantly lower levels of long-chain aldehydes and several hydrocarbons. Dietary supplementation with AC + OL showed a significantly higher abundance of (Z)-2-heptenal and 2-n-butylfuran. While antioxidant supplementation had only marginal effects on the volatile profile, barrows showed significantly higher levels of lipid oxidation-derived volatiles, including aldehydes and ketones, compared to gilts. Significant interactions among AO, dietary flavouring prototypes and sex were observed for specific hydrocarbons, especially observed with AC. In conclusion, dietary acorn flavouring prototype supplementation, either alone or with an olive flavouring prototype, has the potential to modulate the volatile profile of pork. Further sensory analysis is required to validate the organoleptic impact of these chemical variations.

This study aimed to evaluate two feeding strategies on pork quality in organic farming using 77 non-castrated male pigs (Piétrain × Large White) reared in two batches, each including two groups. Male littermates were allocated to either a Control group (C, n = 37), fed following the organic specifications, or to a group receiving an organic test feed mainly based on French raw materials and containing more fibre and omega-3 fatty acids (Bio+, n = 40). Within batch, each group was reared in one pen from the same building on deep straw bedding with free outdoor access, with ad libitum feeding from around 33 kg until slaughter at around 128 kg of live weight. Loin meat samples were analysed by a trained sensory panel and by SPME-GC-MS to identify the main volatile compounds. Meat from Bio+ pigs showed a significantly more intense red colour (P < 0.01), but lower aromatic persistency (P < 0.05) and tended to be less tender (P = 0.08) than meat from C pigs. None of the samples were qualified as boar tainted. A total of 27 volatile compounds were quantified, with more compounds present in Bio+ pigs, probably due to the greater diversity of raw ingredients in the feeds. The multi-dimensional analyses enabled to observe relationships between volatile compounds and sensory traits but did not differentiate the two feeding strategies. Bio+ feeding strategy compared to C influenced some organoleptic characteristics (red colour of raw meat, aromatic persistency) without modifying the texture, odour and flavour of organic cooked pork.

This study evaluated the effects of a fibre- and fat-rich by-products-based diet and the intramuscular fat (IMF) content on volatile compounds in pork. Meat samples were collected from sixteen gilts included in a feeding trial. Half of the animals were fed a conventional diet based on wheat, maize, barley and soybean meal, whereas the other half were fed a by-products-based diet that contained corn germ meal, malt sprouts, crispbread meal and proticorn, but no cereals or soya. Within each dietary treatment, four meat samples were selected from pigs in the upper quartile of IMF content (average 2.40 % +/- 0.18 %, n = 8) and four from the lower quartile of IMF content (average 1.45 % +/- 0.10 %, n = 8). SPME-GC-MS was used to evaluate the volatile profile of pork. A total of 45 volatile compounds were identified in the cooked pork samples. Aldehydes were the predominant chemical class in terms of the number of identified volatile compounds. No diet x IMF interaction was observed for the abundance of volatile compounds. Dietary treatment and IMF content significantly influenced the abundance of one and two aldehydes, respectively. Hexanal was more abundant in the meat of animals fed the conventional diet compared to the diet based on by-products. Tridecanal and tetradecanal were less abundant in pork with higher IMF levels. As precursors of volatile compounds, fatty acids were also analysed in the raw meat samples by GC. The concentrations of most fatty acids were higher in pork with higher IMF content but were not affected by diet. In conclusion, the volatile compounds profile of pork was only marginally affected by IMF content and feeding a by-products-based diet in the present study.

It was hypothesized that differences in production system and muscle type may influence the formation of lipid oxidation products (LOP) as well as protein oxidation (protein carbonyl compounds, PCC) during the in vitro gastrointestinal digestion of chicken meat. To test our hypothesis, we investigated the formation of LOP and PCC after heating and in vitro gastrointestinal digestion of conventional and organic chicken breast and thigh meat and Wooden Breast meat. Prior to the in vitro digestion, thigh and breast meat was minced and heated. Digests of organic thigh meat had significantly higher levels of all LOP measured compared to conventional thigh meat (between +37% and +173%). Lower levels of LOP were found in digests of breast meat regardless of the production system and Wooden Breast phenotype. LOP correlated positively with heme-Fe and polyunsaturated fatty acids, negatively with anserine, and not with carnosine and α-tocopherol. PCC levels were significantly higher in thigh meat than in breast meat after heating (+43%) and digestion (+25%), irrespective of the production system. Overall, organic thigh meat exhibited the highest oxidative sensitivity during digestion. The cut-dependent differences in composition and oxidative susceptibility between organic and conventional chicken highlight the need for further research to assess potential health implications.

In the present study, it was investigated if glucose addition (3 or 5%) to pork stimulates glycoxidation (pentosidine, PEN), glycation (Maillard reaction products, MRP), lipid oxidation (4-hydroxy-2-nonenal, 4-HNE; hexanal, HEX; thiobarbituric acid reactive substances, TBARS), and protein oxidation (protein carbonyl compounds, PCC) during various heating conditions and subsequent in vitro gastrointestinal digestion. An increase in proteinbound PEN level was observed during meat digestion, which was significantly stimulated by glucose addition (up to 3.3 -fold) and longer oven-heating time (up to 2.5 -fold) of the meat. These changes were accompanied by the distinct formation of MRP during heating and digestion of the meats. Remarkably, stimulated glyc(oxid)ation was accompanied by increased protein oxidation, whereas lipid oxidation was decreased, indicating these reactions are interrelated during gastrointestinal digestion of meat. Glucose addition generally didn 't affect these oxidative reactions when pork was packed preventing air exposure and oven-heated until a core temperature of 75 degrees C was reached.

The formation of sulfur metabolites during large intestinal fermentation of red meat may affect intestinal health. In this study, four muscle sources with varying heme-Fe content (beef, pork, chicken and salmon), with or without fructo-oligosaccharides (FOS), were exposed to an in vitro gastrointestinal digestion and fermentation model, after which the formation of sulfur metabolites, protein fermentation metabolites, and short (SCFA) and branched (BCFA) chain fatty acids was assessed. When FOS were present during muscle fermentation, levels of SCFA (+54%) and H2S (+36%) increased, whereas levels of CS2 (-37%), ammonia (-60%) and indole (-30%) decreased, and the formation of dimethyl sulfides and phenol was suppressed. Red meat fermentation was not accompanied by higher H2S formation, but beef ferments tended to contain 33 to 49% higher CS2 levels compared to the ferments of other muscle sources. In conclusion, there is a greater effect on sulfur fermentation by the addition of FOS to the meats, than the intrinsic heme-Fe content of meat.

This study aimed to investigate the kinetics of dietary GSH in the gastrointestinal tract and the effect of GSH on the intestinal redox status of weaned piglets. Forty-eight piglets with an average age of 26 days and an average body weight of 7.7 kg were used in this study. The piglets were divided into three treatment groups including the control group with a basal diet (CON) and two GSH groups with a basal diet supplemented with 0.1% GSH (LGSH) and 1.0% GSH (HGSH), respectively. The basal diet did not contain any GSH. The experiment lasted for 14 days, with eight animals sampled from each group on d5 and 14. The parts of 0–5%, 5–75%, and 75–100% of the length of the small intestine were assigned to SI1, SI2, and SI3. The results showed that GSH almost completely disappeared from the digesta at SI2. However, no difference in the GSH level in mucosa, liver, and blood erythrocytes was found. The level of cysteine (CYS) in SI1 digesta was significantly higher in HGSH than CON and LGSH on d14, and similar findings were observed for cystine (CYSS) in SI3 digesta on d5. The CYSS level in HGSH was also significantly higher than LGSH in the stomach on d14, while no CYS or CYSS was detected in the stomach for control animals, indicating the breakdown of GSH to CYS already occurred in the stomach. Irrespective of the dietary treatment, the CYS level on d14 and the CYSS level on d5 and 14 were increased when moving more distally into the gastrointestinal tract. Furthermore, the mucosal CYS level was significantly increased at SI1 in the LGSH and HGSH group compared with CON on d5. Glutathione disulfide (GSSG) was recovered in the diets and digesta from the LGSH and HGSH group, which could demonstrate the auto-oxidation of GSH. It is, therefore, concluded that GSH supplementation could not increase the small intestinal mucosal GSH level of weaned piglets, and this could potentially relate to the kinetics of GSH in the digestive tract, where GSH seemed to be prone to the breakdown to CYS and CYSS and the auto-oxidation to GSSG.

Dry-aging of beef comprises the storage of carcasses and (sub)primal cuts at a low temperature and relative humidity for a prolonged period, aiming to increase the sensory quality of meat. Limited data are available on the survival and potential growth of pathogens on the surface of beef during dry-aging. Therefore, this study evaluates the changes in Salmonella, Shiga toxin-producing Escherichia coli O157:H7 and Listeria monocytogenes counts during dry-aging. A mixture of pathogenic strains was inoculated on the surface of beef loins, which were stored under four different process conditions (2 °C and 6 °C × relative humidity 75 and 85% during 42 days). Salmonella and E. coli O157:H7 counts significantly decreased during dry-aging. The daily reductions varied from -0.07 to -0.14 log10 CFU and from -0.09 to -0.14 log10 CFU, respectively, depending on the loin, matrix and condition. The reduction of L. monocytogenes was slower, with a maximum of -0.07 log10 CFU/day. L. monocytogenes counts increased with 1.0 log10 CFU on the lean meat of one loin with pH > 6.0 at the end of dry-aging, indicating that this pathogen can potentially grow under certain dry-aging conditions.

Metabolites are substances that are formed within our bodies that help us live and grow. Examples include glucose and vitamin D. When changes happen in our bodies, like when we get sick, these metabolites can change. By studying metabolite changes, using a method called metabolomics, we can learn a lot about diseases, what causes them, and how to avoid them. We know that eating foods like fish, fruits, and vegetables is healthy. Eating too much red and processed meat, however, increases our chances of developing certain types of cancer. Unfortunately, we still do not understand why that is. It could be that there are unhealthy, toxic elements or substances in the meat itself or that there are toxic metabolites formed during or after the digestion of red and processed meat. To find out, we must journey into the gut, using metabolomics!

The objective of this study was to evaluate the effect of aging period (0, 3, 6 or 9 weeks), aging temperature (2 versus 6 °C at 75% relative humidity, experiment 1) and relative humidity (70 versus 90% at 2 °C, experiment 2) on the sensory traits, oxidative stability and proteolysis of Belgian Blue beef. For each experiment, eight loins (M. longissimus thoracis et lumborum) from four animals (left and right side) were assigned to one of the two treatments (n = 4). Results showed no further tenderization after three weeks of aging, whereas metmyoglobin formation and lipid oxidation increased until nine weeks of aging (P < 0.05). During the nine weeks of aging, atypical flavor, odor and flavor intensity was affected (P < 0.05). This was accompanied by an increase of small peptides and other nitrogenous compounds. Aging temperature and relative humidity had only a very limited effect on the quality traits.

Performance (from 10 weeks until slaughter), carcass and meat quality, and effectiveness of immunocastration was compared in crossbred offspring of stress positive (BP+) and negative (BP-) Belgian Piétrain and Canadian Duroc (CD) given the second vaccination of Improvac® at different times (4, 6, 8 weeks before slaughter). CD offspring had a significantly higher daily gain (DG) and feed intake (DFI), and lower predicted lean meat percentage (LMP) and dressing yield compared to BP+ and BP-, while feed conversion ratio (FCR) did not differ. CD offspring had significantly lower drip loss and higher pHi, intramuscular fat content than BP+ and BP- (except for pHi). No significant effect of vaccination time on DG nor FCR was observed. Predicted LMP tended to increase as time-post injection decreased, while meat quality was minor affected. Earlier vaccination had no effect on the effectiveness of immunocastration based on testosterone and GnRH-binding.

Mechanisms explaining epidemiological associations between red (processed) meat consumption and chronic disease risk are not yet elucidated, but may involve oxidative reactions, microbial composition alterations, inflammation and/or the formation of toxic bacterial metabolites. First, in vitro gastrointestinal digestion of 23 cooked beef-lard minces, to which varying doses of nitrite salt (range 0-40 g/kg) and sodium ascorbate (range 0-2 g/kg) were added, showed that nitrite salt decreased protein carbonylation up to 3-fold, and inhibited lipid oxidation, demonstrated by up to 4-fold lower levels of 'thiobarbituric acid reactive substances', 32-fold lower 4-hydroxynonenal, and 21-fold lower hexanal values. The use of ascorbate increased the antioxidant effect of low nitrite salt levels, whereas it slightly increased protein carbonylation at higher doses of nitrite salt. The addition of a low dose of ascorbate without nitrite salt slightly promoted oxidation during digestion, whereas higher doses had varying antioxidant effects. Second, 40 rats were fed a diet of cooked chicken- or beef-lard minces, either or not cured, for three weeks. Beef, compared to chicken, consumption increased lipid oxidation (2- to 4-fold) during digestion, and gut protein fermentation (cecal iso-butyrate, (iso-)valerate, and fecal indole, cresol), but oxidative stress and inflammation were generally not affected. Cured, compared to fresh, meat consumption significantly increased stomach protein carbonylation (+16%), colonic Ruminococcaceae (2.1-fold) and cecal propionate (+18%), whereas it decreased cecal butyrate (-25%), fecal phenol (-69%) and dimethyl disulfide (-61%) levels. Fecal acetaldehyde and diacetyl levels were increased in beef-fed rats by 2.8-fold and 5.9-fold respectively, and fecal carbon disulfide was 4-fold higher in rats consuming cured beef vs. fresh chicken. Given their known toxicity, the role of acetaldehyde and carbon disulfide in the relation between meat consumption and health should be investigated in future studies.

This study was performed to investigate meat quality traits of loin and ham of commercial pigs as affected by genetic differences in carcass and growth traits of the parent lines. Three hybrid sow lines were crossbred with two types of Belgian Piétrain with different breeding goals (BPgrowth and BPcarcass emphasizing daily growth and carcass conformation, respectively). Pig live performance and carcass quality of 270 offspring were measured, and meat quality of the loin and (cooked) ham was evaluated on 216 animals. Despite the differences in pig live performance and carcass quality for sow line, little effect on meat quality was observed. Only a lower (p < 0.05) intramuscular fat content of ham and a tendency (p < 0.1) toward lower cooking yield was observed in offspring of the sow line with the highest versus the lowest carcass lean content. Loin traits were only weakly associated with fresh and cooked ham quality traits.

Red meat has been associated with an increased cardiovascular disease (CVD) risk, possibly through gut microbial-derived trimethylamine-N-oxide (TMAO). However, previous reports are conflicting, and influences from the background diet may modulate the impact of meat consumption. This study investigated the effect of red and white meat intake combined with two different background diets on urinary TMAO concentration and its association with the colon microbiome in addition to apparent hepatic TMAO-related activity. For 4 weeks, 32 pigs were fed chicken or red and processed meat combined with a prudent or western background diet. 1H NMR-based metabolomics analysis was conducted on urine samples and hepatic mRNA expression of TMAO-related genes determined. Lower urinary TMAO concentrations were observed after intake of red and processed meat when consumed with a prudent compared to a western background diet. In addition, correlation analyses between urinary TMAO concentrations and relative abundance of colon bacterial groups suggested an association between TMAO and specific bacterial taxa. Diet did not affect the hepatic mRNA expression of genes related to TMAO formation. The results suggest that meat-induced TMAO formation is regulated by mechanisms other than alterations at the hepatic gene expression level, possibly involving modulations of the gut microbiota.

This study was designed to compare performance, carcass and meat quality of crossbred of a hybrid sow x three sire lines, i.e. stress positive Belgian Piétrain (BP), stress negative French Piétrain (FP) and Canadian Duroc (CD). BP offspring had a significantly higher carcass yield (p < .001) and lean meat content (p < .001) in comparison with FP, which was higher than CD. BP offspring had significantly lower pH (p < .05), water-holding capacity (WHC) (p < .001) and intramuscular fat (IMF) (p < .001) content in the loin compared to FP and CD, but these meat quality parameters, with the exception of pH, were superior for CD as compared to FP. In accordance with loin quality, pHi, pHu, WHC and IMF of BP were significantly lower (p < .05) compared to CD in the fresh and cooked ham. Most often, FP offspring could not be differentiated from the other offspring, with the exception of cooking loss of the cooked ham. Trained and consumer taste panels resulted in no significant differences (p > .1) in sensory attributes, however, consumers preffered CD based on ranking.