Level of natural hepatotoxin (Indospicine) contamination in Australian camel meat

Camel meat production for human consumption and pet food manufacture accounts for a relatively small part of overall red meat production in Australia. Reliable statistical data for the Australian production and consumption of camel meat are not available; however, it is estimated that 300,000 feral camels roam within the desert of central Australia, with an annual usage of more than 3000 camels for human consumption, 2000 for pet food manufacture and a smaller number for live export. Despite a small Australian camel meat production level, the usage of camel meat for pet food has been restricted in recent years due to reports of serious liver disease and death in dogs consuming camel meat. This camel meat was found to contain residues of indospicine, a non-proteinogenic amino acid found in certain Indigofera spp., and associated with mild to severe liver disease in diverse animals after dietary exposure to this hepatotoxin. The extent of indospicine-contaminated Australian camel meat was previously unknown, and this study ascertains the prevalence of such residue in Australian camel meat. In this study, indospicine levels in ex situ (95 samples collected from an abattoir in Queensland) and in situ (197 samples collected from camels after field culling in central Australia) camel meat samples were quantitated using a validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The quantitation results showed 46.7% of the in situ- and 20.0% of the ex situ-collected camel meat samples were contaminated by indospicine (more than the limit of detection (LOD) of 0.05 mg kg^–1 fresh weight). The overall indospicine concentration was higher (p < 0.05) in the in situ-collected samples. Indospicine levels detected in the present study are considered to be low; however, a degree of caution must still be exercised, since the tolerable daily intake for indospicine is currently not available for risk estimation.     

Effect of dietary supplementation of Spirulina (Arthrospira platensis) and Thyme (Thymus vulgaris) on rabbit meat appearance,oxidative stability and fatty acid profile during retail display

The objective of this study was to evaluate the effect of Spirulina and Thyme supplementation on rabbit meat during retail display. At weaning 294 rabbits were allocated to 7 different treatments (42 rabbits/treatment). Rabbits of the control group (C) received a diet without any supplementation throughout the experiment (5–11 weeks of age). The other groups were fed diets containing 5% Spirulina (S), 3% Thyme (T) or both supplements (ST) for the whole trial (5–11 weeks; treatments S, T and ST), or for a part of the growing period (8–11 weeks; treatments C–S, C–T and C–ST). Colour parameters, pH, water holding capacity and drip loss were determined on fresh and stored Longissimus dorsi muscle of 5 rabbits/treatment. Spirulina- and Thyme-supplemented diets had a significant effect on redness and yellowness of Longissimus dorsi. Drip loss was significantly reduced in C–T and T groups that also showed the highest content of α-tocopherol and n − 3 fatty acids content and the lower lipid oxidation.     

Zinc oxide nanoparticles loaded active packaging,a challenge study against Salmonella typhimurium and Staphylococcus aureus in ready-to-eat poultry meat

Zinc oxide nanoparticles were prepared using hydrothermal synthesis approach. Formation of zinc oxide nanoparticles were confirmed by using UV–Vis spectrophotometer, Fourier transform infrared spectrometer and X-ray diffractometer. The particles size (≤100 nm) and structure of nanoparticles were studied under scanning and transmission electron microscope. The nanoparticles were used against two prominent foodborne pathogens, Salmonella typhimurium and Staphylococcus aureus and were found highly effective against both of them. The antibacterial activity of the nanoparticles was determined in solid and liquid media using nutrient agar and broth. Zinc oxide nanoparticles loaded active film of calcium alginate was prepared for active packaging against the same foodborne pathogens (S. typhimurium and S. aureus). Presence and distribution of nanoparticles in active film were confirmed with Fourier transform infrared spectrometer, X-ray diffractometer and scanning electron microscopy. Zinc oxide nanoparticles loaded active films showed antibacterial activity against the target bacteria in Petri dish. The film was also used as an active packaging (a challenge study) in ready-to-eat poultry meat against the same pathogens, and reduced the number of inoculated target bacteria from log seven to zero within 10 days of its incubation at 8 ± 1 °C.     

Effect of muscle and intensity of finishing diet on meat quality of foals slaughtered at 15 months

The effect of muscle and intensity of finishing diet on meat quality of foals slaughtered at 15 months was study. For this work, a total of twenty one foals and six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and Psoas major & minor (PM) from two different intensities of finishing diet (1.5 vs. 3 kg/day) were analysed.     

Correlation between instrumental stress and oral processing property of chicken broiler breast under wooden breast myopathy

Wooden breast myopathy affects the quality of fresh and processed chicken breast muscle. The objective of this study was to construct a classification method by instrumental stress, and the effects of wooden breast myopathy on meat quality and oral processing property, and was to explore correlations between stress and oral processing parameters. The severity of wooden breast myopathy was highly correlated to fillet weight (R² = 0.740), thickness (R² = 0.826) and hardness (R² = 0.803) (P < 0.01). The 3D scatter model based on stress is robust and reliable to classify the fillets into four categories (normal, mild, moderate and severe wooden breast fillets), avoiding manual grading. Moisture, fat, collagen, pH, drip loss, cooking loss, thawing loss, purge loss, hardness, gumminess and chewiness significantly increased with the severity of wooden breast myopathy, whereas fat, ash and water/salt-soluble protein contents significantly decreased (P < 0.05). Shear force reached the maximum (36.32 N) when this myopathy was moderate. The myopathy led to an increase in masseter activity and the particle size of the bolus. Significantly higher correlations between stress, Dx(50) (R² = 0.790), Dx(90) (R² = 0.771) and D[4,3] (R² = 0.797) were found (P < 0.01). This study also showed that jaw movement and muscle activity could be used to understand the links between physical property and orally sensory property.     

Extruded meat alternatives made from Maillard-reacted beef bone hydrolysate and plant proteins: part I – Effect of moisture content

This study investigated the effects of moisture content (MC) on the physicochemical properties of extruded meat alternatives made from Maillard-reacted beef bone hydrolysate and plant proteins. Samples were extruded at 170 °C (maximum barrel temperature), at 3.6 kg h⁻¹ (liquid feed rate) and at 1.8, 2.2, 2.6 and 3.0 kg h⁻¹ (dry feed rates) to obtain MC of 60%MC, 56%MC, 52%MC and 49%MC, respectively. Meat alternatives at 52%MC showed the greatest degree of texturisation. However, meat alternatives at 49%MC were the closest in terms of both textural and microstructural properties to reference sample, boiled chicken breast. Results from protein solubility suggested that a large amount of aggregated proteins were associated with hydrogen bonds, while disulphide bonds were the main contributor in the formation of fibrous structure in meat alternatives. Results showed that the change in MC as process parameter played an important role in the formation of fibrous structure in extruded meat alternatives.     

脂质氧化对肉制品中4 类有害物质形成影响的研究进展

肉制品加工过程中往往伴随着脂质氧化的发生，现有研究表明，脂质氧化能影响肉制品中杂环胺、N-亚硝基化合物、晚期糖基化终末产物及多环芳烃等有害物质的生成，这些物质的积累会降低肉制品的食用安全性并危害人体健康。本文综述了肉制品中脂质氧化的机制及氧化产物的反应活性、脂质氧化对肉制品中上述4 类有害物质形成的影响及相关控制措施，以期从控制脂质氧化的角度出发为肉制品安全性生产工艺提供参考。