The Effect of Temperature and Storage Duration on the Quality and Attributes of the Breast Meat of Hens after Their Laying Periods

The purpose of this study was to evaluate the effect of temperature (2 °C and 6 °C) and storage duration on the quality and attributes of hens' breast meat after their laying periods. The study included physicochemical characteristics (pH, drip loss, colour, shear force), microbiological quality (total Enterobacteriaceae family and Pseudomonas count), and sensory quality. Bacterial identification was performed using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The increased meat pH and drip loss was greater at 6 than 2 °C (p < 0.05). An increase in the tenderness of the meat stored at 6 °C was found as early as day 4, as well as at 2 °C on day 8 of storage (p < 0.05). On day 4 of storage, the meat was characterised by a darker colour than on the first day, but the darkening was greater at 6 °C than at 2 °C (p < 0.05). At 6 °C, on day 4 of storage, there was an increase in yellow saturation (b*) of the meat, which was higher at 6 °C than at 2 °C (p < 0.05). At 2 °C, the total bacterial count and number of Pseudomonas spp. in the meat gradually increased along with increasing storage duration, reaching 4.64 log cfu/g and 4.48 log cfu/g, respectively, on the 8th day of storage. At 6 °C, on the sixth day of storage, the total bacterial count in the meat exceeded 7 log cfu/g, considered the limit of microbiological safety. The meat stored at 2 °C had an acceptable sensory quality until the 8th day of storage. The study shows that storage at 2 °C preserves the sensory characteristics and microbiological safety of the hen meat longer at an acceptable level after the laying period. Extended storage life may be of importance to consumers and the meat industry.

Non-Destructive Measuring Systems for the Evaluation of High Oxygen Stored Poultry: Development of Headspace Gas Composition, Sensory and Microbiological Spoilage

As poultry is known to be a perishable food, the use-by date is set in such a way that food safety is guaranteed even with a higher initial bacterial count. This means, however, that some products are wasted, even if they are still safe to eat. Therefore, non-destructive measurement devices might be a good opportunity for individual shelf-life prediction, e.g., in retail. The aim of this study was therefore to use non-destructive measurement devices based on fluorescence quenching (oxygen detection) and mid-infrared laser spectroscopy (carbon dioxide detection) for the monitoring of high-oxygen-packed poultry in different storage conditions. During 15 days of storage, the gas composition of the headspace was assessed (non-destructively and destructively), while total plate count was monitored and a comprehensive sensory evaluation was performed by a trained panel. We were able to demonstrate that in most cases, non-destructive devices have comparable precision to destructive devices. For both storage conditions, the sensory attribute slime was correlated with reaching the critical microbiological value of 107 CFU/g; the attribute buttery was also useful for the prediction of regularly stored poultry. The change in the gas atmosphere as a sign of premature spoilage, however, was only possible for samples stored in irregular conditions.

A Multi-Model Approach to Implement a Dynamic Shelf Life Criterion in Meat Supply Chains

The high perishability of fresh meat results in short sales and consumption periods, which can lead to high amounts of food waste, especially when a fixed best-before date is stated. Thus, the aim of this study was the development of a real-time dynamic shelf-life criterion (DSLC) for fresh pork filets based on a multi-model approach combining predictive microbiology and sensory modeling. Therefore, 647 samples of ma-packed pork loin were investigated in isothermal and non-isothermal storage trials. For the identification of the most suitable spoilage predictors, typical meat quality parameters (pH-value, color, texture, and sensory characteristics) as well as microbial contamination (total viable count, Pseudomonas spp., lactic acid bacteria, Brochothrix thermosphacta, Enterobacteriaceae) were analyzed at specific investigation points. Dynamic modeling was conducted using a combination of the modified Gompertz model (microbial data) or a linear approach (sensory data) and the Arrhenius model. Based on these models, a four-point scale grading system for the DSLC was developed to predict the product status and shelf-life as a function of temperature data in the supply chain. The applicability of the DSLC was validated in a pilot study under real chain conditions and showed an accurate real-time prediction of the product status.

Can Sustainable Packaging Help to Reduce Food Waste? A Status Quo Focusing Plant-Derived Polymers and Additives

The promotion of sustainable packaging is part of the European Green Deal and plays a key role in the EU’s social and political strategy. One option is the use of renewable resources and biomass waste as raw materials for polymer production. Lignocellulose biomass from annual and perennial industrial crops and agricultural residues are a major source of polysaccharides, proteins, and lignin and can also be used to obtain plant-based extracts and essential oils. Therefore, these biomasses are considered as potential substitute for fossil-based resources. Here, the status quo of bio-based polymers is discussed and evaluated in terms of properties related to packaging applications such as gas and water vapor permeability as well as mechanical properties. So far, their practical use is still restricted due to lower performance in fundamental packaging functions that directly influence food quality and safety, the length of shelf life, and thus the amount of food waste. Besides bio-based polymers, this review focuses on plant extracts as active packaging agents. Incorporating extracts of herbs, flowers, trees, and their fruits is inevitable to achieve desired material properties that are capable to prolong the food shelf life. Finally, the adoption potential of packaging based on polymers from renewable resources is discussed from a bioeconomy perspective.

Assessment of the spoilage microbiota in minced free-range chicken meat during storage at 4 C in retail modified atmosphere packages

This study assessed the evolution of spoilage microbiota in association with the changes in pH and concentrations of lactic and acetic acids in retail oxygen-free modified atmosphere (30:70 CO₂/N₂) packages (MAP) of minced free-range chicken meat during storage at 4 °C for 10 days. MAP retarded growth of spoilage lactic acid bacteria (LAB) below 6.5 log cfu/g and fully suppressed growth of pseudomonads, enterobacteria, enterococci, staphylococci and yeasts. Two distinct Latilactobacillus sakei strain biotypes were predominant and Leuconostoc carnosum, Carnobacterium divergens, Latilactobacillus fuchuensis and Weissella koreensis were subdominant at spoilage. The chicken meat pH ranged from 5.8 to 6.1. l-lactate (832 mg/100 g on day-0) decreased slightly on day-7. d-lactate remained constantly below 20 mg/100 g, whereas acetate (0-59 mg/100 g) increased 5-fold on day-7. All MAP samples developed off-odors on day-7 and a strong 'blown-pack' sulfur-type of spoilage on day-10. However, neither the predominant Lb. sakei nor other LAB or gram-negative isolates formed H₂S in vitro, except for C. divergens.

Freshness-based real-time shelf-life estimation of packaged chicken meat under dynamic storage conditions

The current study was performed to develop dynamic quality and shelf-life prediction models using selected index for packaged chicken meat during storage. Generally, the results showed that meat deterioration, with respect to the different quality indices considered in the investigation, proceeds with increasing temperature and storage time. Highly significant (P ≤ 0.01) correlations were obtained between TPC (total plate count) and SI (sensory index) (r = −0.94 to −0.97), coliforms and SI (r = −0.89 to −0.95), and LAB (lactic acid bacteria) and SI (r = −0.93 to −0.98). However, only the microbiological spoilage regarding TPC, whose values ranged from 7.0 to 8.0 log CFU/g under all investigated temperature conditions, were in compliance with the end of sensory shelf-life defined at SI = 5. To develop dynamic quality prediction model, 4 isothermal (0, 4, 10, and 15°C) experiments in 2 batches were performed for TPC evaluation. Growth data were fitted in the Baranyi and Roberts and quadratic polynomial model as the primary and secondary models, respectively. The model was validated under dynamic conditions (0–8°C scenario with periodic 12-h changes). The accuracy and bias factors were estimated to be 1.045 and 0.991 for fluctuating conditions and 1.016 and 1.015 for real-time conditions, respectively, suggesting good applicability of the model. The remaining shelf-life estimation model developed based on mean kinetic temperature showed an even decrease of shelf-life under dynamic conditions in time. The developed model scan can be used for effective monitoring of packaged chicken meat freshness and shelf-life during distribution with temperature fluctuation.

Variability within the dominant microbiota of sliced cooked poultry products at expiration date in the Belgian retail

Sliced cooked poultry products are susceptible to bacterial spoilage, notwithstanding their storage under modified-atmosphere packaging (MAP) in the cold chain. Although the prevailing bacterial communities are known to be mostly consisting of lactic acid bacteria (LAB), more information is needed about the potential variation in species diversity within national markets. In the present study, a total of 42 different samples of sliced cooked poultry products were collected in the Belgian retail and their bacterial communities were analysed at expiration date. A total of 629 isolates from four different culture media, including plate count agar for the total microbiota and de Man-Rogosa-Sharpe (MRS), modified MRS, and M17 agar as three selective agar media for LAB, were subjected to (GTG)₅-PCR fingerprinting and identification by gene sequencing. Overall, Carnobacterium, Lactobacillus, and Leuconostoc were the dominant genera. Within each genus, the most encountered isolates were Carnobacterium divergens, Lactobacillus sakei, and Leuconostoc carnosum. When comparing samples from chicken origin with samples from turkey-derived products, a higher dominance of Carnobacteria spp. was found in the latter group. Also, an association between the dominance of lactobacilli and the presence of added plant material and lactate salts was found.