Carbon dioxide flavour taint in modified atmosphere packed beef steaks

The Effect of Packaging Methods, Storage Time and the Fortification of Poultry Sausages with Fish Oil and Microencapsulated Fish Oil on Their Rheological and Water-Binding Properties

The aim of the study was to investigate how liquid fish oil and microencapsulated oil additives influenced the rheological characteristics and the dynamics of water binding in vacuum-packed (VP) and modified-atmosphere-packed (MAP) poultry sausages during 21-day storage. In contrast to the control sample, the sausages enriched with microencapsulated fish oil (MC) were characterised by the greatest ability to accumulate deformation energy. The elastic properties of all sausage variants increased significantly in the subsequent storage periods, whereas the dynamic viscosity of the samples tended to decrease. This phenomenon was confirmed by the gradual reduction of water activity (Aw) in all sausages in the subsequent storage periods. The packaging method influenced the dynamics of water binding in an oil-additive-form-dependent manner. During the storage of the VP and MAP sausages, in samples with the fish oil additive the T1 value tended to increase while the Aw decreased. The T1 value in the MAP MC sample was similar. The FO additive resulted in greater mobility of both proton fractions in the MAP samples than in the VP samples. There were inverse relationships observed in the MC samples. The NMR tests showed that the VP samples with the MC additive were slightly better quality than the other samples.

The pathogenic and spoilage bacteria associated with red meat and application of different approaches of high CO2 packaging to extend product shelf-life

With the fast-global development of packaging techniques, the potential antimicrobial effect of CO₂, as a safe, cheap and readily available gas, makes it the integral component for packaging of meat products. The associated spoilage and/or pathogenic bacteria on raw meat may respond in different ways to elevated CO₂ concentrations. The growth of some aerobic Gram-negative bacteria such as Pseudomonas spp. is significantly inhibited but some LAB bacteria may be allowed to grow faster and dominate the product. The antimicrobial efficacy of enriched CO₂ packaging is attributed to the rate of CO₂ solubility in the product which is itself affected by the level of headspace CO₂, product pH, temperature and the ratio of headspace gas to product (G:P). This review, first, explores the varied range of beef and sheep meat spoilage and pathogenic bacteria and the intrinsic and extrinsic parameters that may influence the pattern of microbial growth and meat spoilage rate during storage. Then, the antimicrobial mechanism of elevated CO₂ packaging will be discussed and the different approaches of achieving enriched CO₂ packaging i.e. the traditional technique of flushing a desired gas mixture and/or using the new commercially developed CO₂ emitters will then be compared in terms of their strengths, limitations and technical mode of action.

The Influence of Packing Methods and Storage Time of Poultry Sausages with Liquid and Microencapsulated Fish Oil Additives on Their Physicochemical, Microbial and Sensory Properties

The aim of the study was to evaluate the influence of refined fish oil additives in liquid and microencapsulated forms, packing method (VP—vacuum packing, MAP—modified atmosphere packing) and storage time (1, 7, 14, 21 days) on selected physicochemical, microbiological and sensory characteristics of minced poultry sausage. Principle component analysis (PCA) showed that the fish oil additive, packing method and storage time significantly influenced some of the physicochemical characteristics of the sausages. The pH value was negatively correlated with the type of sample and packing method. The water activity decreased along with the storage time. The sausages with microcapsules had distinguishable hardness, gumminess and chewiness than the other samples. This tendency increased in the subsequent storage periods. The packing method and storage time of the samples had a statistically significant influence on the growth of the total colony count and count of lactic acid bacteria (p < 0.05). The most aerobic bacteria were found in the control sample, and the least in the sample with microcapsules, regardless of the packing method. The use of MAP and the addition of microcapsules resulted in the lowest microbiological contamination of the sausages. The sensory analysis made by a trained panel did not show any significant differences between the samples. After 21-day storage of the sausages there was a slight decrease in some of the sensory parameters, e.g., color, smell, taste. The liquid oil and microencapsulated oil additives in the meat filling did not negatively affect the taste or any physicochemical characteristics of the meat products. From the microbiological perspective, there were better effects from the MAP method.

Effects of whey protein films on the quality of thawed bigeye tuna (Thunnus obesus) chunks under modified atmosphere packaging and vacuum packaging conditions

To improve the quality of modified atmosphere (60% CO₂/15% O₂/25% N₂)-packaged or vacuum-packaged bigeye tuna (Thunnus obesus) chunks, an edible film containing whey protein isolates (WPI) were added. During storage at 2 °C, the samples coated with WPI prior to packaging exhibited slower microbial growth, thiobarbituric acid (TBA), and total volatile basic-nitrogen (TVB-N) values than did those without films. On comparing the two formulations of WPI with 4 and 8% (v/v) glycerol, it was observed that WPI containing 8% glycerol induced more severe weight loss but retarded the lipid oxidation more effectively. The usage of WPI films with 8% glycerol is proved to be helpful to enhance the effect of modified atmosphere packaging on the quality of tuna, as the samples (MAP-2) displayed the lowest bacterial counts (3.63 log CFU/g) and TBA (0.349 mg malondialdehyde (MDA)/kg) and TVB-N (12.94 mg N/100 g) contents.

Influence of vacuum-ageing duration of whole beef on retail shelf life of steaks packaged with oregano (Origanum vulgare L.) active film under high O2

Beef Longissimus lumborum (LL) was no aged (LL0), aged for 7 days (LL7) and 14 days (LL14) under vacuum at 1 ± 1 °C. The obtained beefsteaks were packaged in high oxygen (Hi-O2) with active packaging (AP) during 13-21 days at 1 ± 1 °C. Redness (CIE a* values), metmyoglobin percentage (MetMb%), total flora (PCA), thiobarbituric acid-reactive substances (TBA-RS), instrumental tenderness (Warner-Bratzler shear force: WBSF), and sensory analyses were performed. The various variables differed amongst the ageing times and packaging systems (AP vs. control). Three and ten additional days of retail shelf life were observed for steaks from LL7 and LL14, respectively. AP increased efficiently the retail shelf life of beefsteaks, but did not affect meat tenderness. The extended ageing from 7 to 14 days also induced higher tenderness in beefsteaks and did not show any affect negative effect on other quality parameters. Innovative technology referring to ageing under vacuum combined with Hi-O2 MA/AP would be desirable for beefsteaks during display and constituted a good alternative for meat supermarkets.

Current topics in active and intelligent food packaging for preservation of fresh foods

The purpose of this review is to provide an overview of current packaging systems, e.g. active packaging and intelligent packaging, for various foods. Active packaging, such as modified atmosphere packaging (MAP), extends the shelf life of fresh produce, provides a high-quality product, reduces economic losses, including those caused by delay of ripening, and improves appearance. However, in active packaging, several variables must be considered, such as temperature control and different gas formulations with different product types and microorganisms. Active packaging refers to the incorporation of additive agents into packaging materials with the purpose of maintaining or extending food product quality and shelf life. Intelligent packaging is emerging as a potential advantage in food processing and is an especially useful tool for tracking product information and monitoring product conditions. Moreover, intelligent packaging facilitates data access and information exchange by altering conditions inside or outside the packaging and product. In spite of these advantages, few of these packaging systems are commercialized because of high cost, strict safety and hygiene regulations or limited consumer acceptance. Therefore more research is needed to develop cheaper, more easily applicable and effective packaging systems for various foods.

A combination of modified atmosphere and antimicrobial packaging to extend the shelf-life of beefsteaks stored at chill temperature

An antimicrobial polyethylene (PE) film was obtained by coating a nisin-based antimicrobial solution. PE sheets were coated on both sides and were used for the packaging of beefsteaks to be stored in air or modified atmosphere packaging (MAP, 60% O₂-40% CO₂). Microbial populations, species diversity, headspace volatile organic compounds, colour and sensory properties were monitored after 0, 1, 7 and 12 days of storage at 4 °C. The viable counts showed that there was an effect of MAP and antimicrobial film on the development of all the spoilage associated microbial populations. Carnobacterium spp., Brochothrix thermosphacta, Pseudomonas fragi and Rhanella aquatilis were found in most of the samples. C. maltaromaticum was identified in MRS bulk cells from samples stored in air as well as MAP. Quantitative data of headspace-SPME-GC/MS analysis showed that during storage the production of volatile organic compounds (VOCs) was affected by the use of the treated film and the MAP storage. Compounds such as phenylethylalcohol, nonanal, decanal and ethylbutanoate were produced only from 7 to 12 day of storage and only in the samples stored in air. In agreement with the microbiological and VOCs data, the meat stored in active packaging scored the best rankings in the sensory evaluation. Principal component analysis of microbial, sensory and instrumental data showed that beefsteaks stored with the combination of MAP and active packaging for 12 days at 4 °C differed from the other samples that were more associated to high microbial loads, VOCs concentration and meat off odour perception. In conclusion, the antimicrobial sheets in combination with MAP storage at 4 °C were effective for the storage of beefsteaks by retarding the growth of spoilage bacteria, determining lower concentration of VOCs and keeping acceptable levels of colour and other sensory parameters for more than 10 days.