Microbiological quality and safety of vacuum-packaged white-tailed deer meat stored at 4 °C

Vacuum packaging is widely used for extending the shelf life of commercial fresh meat products. It also ensures product hygiene during distribution and storage. However, very little information exists concerning the effects of vacuum packaging on the shelf life of deer meat. One of our aims was to evaluate how storage under vacuum at 4 °C affects the microbial quality and safety of white-tailed deer (Odocoileus virginianus) meat cuts. This was assessed in a longitudinal study based on sensory analyses and measurements of (1) mesophilic aerobic bacteria (MAB), (2) lactic acid bacteria (LAB), (3) enterobacteria (EB), (4) and Escherichia coli (EC) counts, and the presence of foodborne pathogens (Campylobacter, Salmonella, stx-harbouring E. coli (STEC), Yersinia and Listeria). Microbiomes were additionally investigated by 16S rRNA gene amplicon sequencing at the time of spoilage. In total, 50 vacuum-packaged meat cuts from the carcasses of 10 wild white-tailed deer harvested in southern Finland in December 2018 were analysed. A significant (p < 0.001) drop in the odour and appearance scores and a significant increase in MAB (p < 0.001) and LAB (p = 0.001) counts of the vacuum-packaged meat cuts were observed after 3 weeks of storage at 4 °C. A very strong correlation (rs = 0.9444, p < 0.001) between the MAB and LAB counts were found during the 5-week sampling period. Clear spoilage changes, manifested as sour off-odours (odour scores ≤2) and pale colour, were detected in the meat cuts spoilt after 3-week storage. High (≥8 log₁₀ cfu/g) MAB and LAB counts were also detected. According to the 16S rRNA gene amplicon analyses, Lactobacillus was the dominant bacterial genus in these samples, demonstrating that LAB can cause rapid spoilage of vacuum-packaged deer meat cuts stored at 4 °C. The rest of the samples were spoilt after four or five weeks of storage, and a vast number of bacterial genera were identified in them. Listeria and STEC were detected by PCR in 50 % and 18 % of the meat cut samples, respectively, which may indicate a public health problem. Our results demonstrate that it is very challenging to ensure the quality and safety of vacuum-packaged deer meat stored at 4 °C, and freezing is therefore recommended to prolong the shelf life.

The Influence of Sensory Characteristics of Game Meat on Consumer Neuroperception: A Narrative Review

Game meat contains bioactive compounds that directly influence the formation of a rich reservoir of flavor precursors that produce specific sensory properties. Quality is considered one of the most influential determinants of consumer behavior, but the interpretation of this concept differs between consumers. Although recognized for its quality, its unique sensory characteristics (smell, taste, aroma) may have a major impact on consumer perception. The aim of this review is to describe the consumer behavior regarding game meat through elements of neuroperception, using methods of analysis, observation, and interpretation of scientific information from the literature. Following the analysis of published papers on this topic, it was shown that external factors influencing the biological basis of behavior could provide explanations for the acceptance or rejection of this type of meat and solutions. Neuroperception can explain the mechanism behind consumer decision-making. The influence of extrinsic factors (environment, mood, emotions, stress) shapes the perception of the quality attributes of game meat, the unique sensory characteristics of game meat passing through a primary filter of sensory receptors (eyes, nose, tongue, etc). Game meat is darker and tougher (compared to meat from domestic animals), and the taste and smell have the power to trigger memories and change the mood, influencing consumer behavior. Understanding consumer attitudes towards game meat in relation to quality attributes and the physiology of sensory perception can provide important insights for food industry professionals, processors, sensory evaluators, and researchers.

Vacuum Packaging Maintains Fresh Characteristics of Previously Frozen Beef Steaks during Simulated Retail Display

The impact of frozen storage on beef steaks prior to the retail setting may result in changes to the quality and safety of the packaged meat. Therefore, the objective of the current study was to evaluate fresh characteristics on previously frozen steaks during a simulated retail display. Steaks were allocated to one of three packaging treatments (MB, MDF, MFS) and stored frozen (−13 °C) for 25 days in the absence of light. After thawing, steaks were stored in a lighted retail case at 3 °C and evaluated for instrumental surface color, pH, purge loss, lipid oxidation, and microbial spoilage organisms throughout the 25-day fresh display period. There was an increase (p < 0.05) for aerobic plate counts and lipid oxidation from day 20 through 25 on steaks packaged in MFS and MDF, respectively. Steaks packaged in MB were redder (p < 0.05) and more vivid (C*) as storage time increased. Whereas lipid oxidation was greater (p < 0.05) throughout the entire display for steaks packaged in MFS and MDF. It is evident that barrier properties of MB limiting oxygen exposure of the steak preserved fresh meat characteristics after frozen storage. Results from the current study suggest that vacuum packaging films can aid in retarding detrimental effects caused by frozen storage after placing the steaks in fresh retail conditions.

A multifunctional study of naturally occurring pyrazines in biological systems; formation mechanisms, metabolism, food applications and functional properties

Natural pyrazines, mainly methyl- or ethyl-substituted forms, are commonly applied as flavor ingredients in raw and roasted food. Meanwhile alkylpyrazines are used as food preservatives due to their effective antimicrobial action. These natural pyrazines are widely distributed in several biological systems such as plants, animals, and insects; each with respective physiological role. Besides, pyrazines are formed in food via thermal treatment and fermentation. This review presents the most comprehensive overview of pyrazines with correlation to their chemical structures and different applications with emphasis on their food applications. The major part deals with pyrazines generated in thermally treated food, reaction mechanisms highlighting factors and optimum conditions affecting their production. Additionally, the several metabolic reactions mediating for pyrazines metabolism in humans and excretion via the kidney are discussed and on context to their effects. Lastly, a review of the different techniques applied for pyrazines isolation, detection and quantitation is presented. The study provides future considerations and direction of research on this important dietary component and their applications. Pyrazines multifunctional chemistry is of value to the food sector, by presenting the best practices for their production whilst the detrimental effects are minimized.

Effect of frozen storage on the lipid oxidation, protein oxidation, and flavor profile of marinated raw beef meat

This study aimed to evaluate the effects of long-term frozen storage on the lipid oxidation, protein oxidation, and flavor profile of marinated raw beef meat. Twenty-eight volatiles were identified in all the samples during different times of frozen storage using HS-SPME-GC-MS. Frozen storage affected the contents of flavor compounds, in which their concentrations fluctuated along with the frozen storage. Partial least squares-discriminant analysis screened six flavors as markers, indicating the effect of frozen storage in all the beef samples. They included octanal, 2-ethyl-1-hexanol, benzeneacetaldehyde, 1-heptanol, isoeugenol, and hexanal. Most of the screened markers belonged to aldehydes and alcohols, indicating that these components were derived from lipid oxidation. Thiobarbituric acid reactive substances significantly increased in the first two months of frozen storage and then decreased slightly. Carbonyl content was increased linearly in all the samples during frozen storage.

Post-mortem ultrasound and freezing of rabbit meat: Effects on the physicochemical quality and weight loss

High intensity ultrasound (HIU) is a technique with the potential to improve meat quality, however, more research is needed on its application within the chain of cold storage and freezing. This study evaluates the effect of HIU (40 kHz, 9.6 W/cm2, 20 and 40 min) and post-mortem development on the yield and physicochemical quality of rabbit meat in samples treated with HIU pre- and post-storage in a freezer (120 h at -20 °C). Twenty rabbit carcasses were vacuum packed 12 h post-mortem, placed in a fridge at 4 °C for 24 h, and divided in two groups (HIU application before or after freezing), before assigning the treatments. The results show that HIU before freezing produced intense and bright orange-yellow colours, whereas its application after freezing resulted in pale red tones. HIU application accelerates rigor mortis resolution when it is applied before freezing and causes a significant decrease in pH immediately following the HIU treatment. Post-freezing application of HIU is not recommended because it considerably increased weight loss and toughening of the meat when long exposure times were used (40 min). In contrast, a short treatment duration with HIU mitigated the effects of freezing and produced significant increases in water-holding capacity (WHC) after cold storage. The yield (weight loss) of the rabbit meat was not affected when HIU was applied pre-freezing. The application of HIU pre-freezing constitutes a promising technology because it increased the tenderness and the WHC of rabbit meat. However, more research is needed to improve the appearance before scaling up to industrial levels.

Standardized Extraction Techniques for Meat Analysis with the Electronic Tongue: A Case Study of Poultry and Red Meat Adulteration

The electronic tongue (e-tongue) is an advanced sensor-based device capable of detecting low concentration differences in solutions. It could have unparalleled advantages for meat quality control, but the challenges of standardized meat extraction methods represent a backdrop that has led to its scanty application in the meat industry. This study aimed to determine the optimal dilution level of meat extract for e-tongue evaluations and also to develop three standardized meat extraction methods. For practicality, the developed methods were applied to detect low levels of meat adulteration using beef and pork mixtures and turkey and chicken mixtures as case studies. Dilution factor of 1% w/v of liquid meat extract was determined to be the optimum for discriminating 1% w/w, 3% w/w, 5% w/w, 10% w/w, and 20% w/w chicken in turkey and pork in beef with linear discriminant analysis accuracies (LDA) of 78.13% (recognition) and 64.73% (validation). Even higher LDA accuracies of 89.62% (recognition) and 68.77% (validation) were achieved for discriminating 1% w/w, 3% w/w, 5% w/w, 10% w/w, and 20% w/w of pork in beef. Partial least square models could predict both sets of meat mixtures with good accuracies. Extraction by cooking was the best method for discriminating meat mixtures and can be applied for meat quality evaluations with the e-tongue.

Water holding capacity of Swamp Buffalo muscles raised with and without proper herd health

Fresh meat is composed of 70-75% water. Meanwhile, water holding capacity (WHC) affects storage quality, appearance, eating experience, and also contributes to loss of profit for meat entrepreneurs. WHC is influenced by the species, sex, breed, farming practices, as well as post-slaughter storage and handling. Swamp buffalo meat is leaner compared to cattle, goats, and sheep. Therefore, this study aims to determine the WHC of swamp buffalo muscles raised with two herd health programs at different aging periods. A total of 24 months old male swamp buffalo (n=4) was raised with a proper herd health protocol (HHP) and another (n=6) without a proper herd health protocol (NHHP). The drip loss (DL), thawing loss (TL), and cooking loss (CL) for longissimus dorsi (LD), supraspinatus (SS), and semitendinosus (ST) muscles were evaluated on day 1, 7, and 14. Based on the results, only SS and ST from NHHP showed significant differences (P≤0.05), while DL, LD, SS, and ST of the HHP and NHHP also differed significantly (P≤0.05). Furthermore, the TL and CL for all the muscles showed significant differences (P≤0.05) at day 7 of aging in the NHHP group, while on day 14, both were significantly higher in LD and ST muscles of NHHP compared to the HHP group. Therefore, the results showed that the muscles of the HHP group had a better WHC compared to NHHP.