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.

Shelf-life extension of pomegranate arils using chitosan nanoparticles loaded with Satureja hortensis essential oil.

BACKGROUND: This study was conducted in two parts to improve the antimicrobial activity and stability of Satureja hortensis essential oil (SEO) and its impacts on the quality of pomegranate arils. In the first part, SEO was encapsulated by an ionic gelation technique into 142.2-267.7 nm chitosan nanoparticles (CSNPs). In the second part of the experiment, the CSNPs and CSNPs-SEO were applied to improve storability of pomegranate arils. Arils were dipped in water (control), CSNPs and CSNPs-SEO for 5 min. After superficial water removal, arils were packed into polystyrene boxes and stored at 5 °C for 18 days. RESULTS: Based on spectrophotometry analysis, the encapsulation efficiency (EE) of SEO-loaded CSNPs (CSNPs-SEO) decreased from 26.57% to 7.41% and their loading capacity (LC) increased from 4.72% to 6.17%, respectively, upon increasing the initial SEO content from 0.125 to 0.5 g g-1 of chitosan. Phytochemicals and water content were maintained, and microbial counts were reduced in the coated arils during storage. Total phenol and antioxidant activity decreased during storage. At the end of storage, the highest total phenol content (2980.0 mg gallic acid equivalents L-1 ) was found in arils treated with CSNPs-SEO, whereas ascorbic acid content was maximal (6.32 mg L-1 ) in arils treated with CSNPs. The encapsulation of savory essential oil in chitosan nanoparticles did not have undesirable effects in pomegranate arils. CONCLUSION: Pre-storage treatment of pomegranate arils with CSNPs-SEO could be considered a beneficial treatment to better maintain the biochemical and sensorial quality during storage. © 2020 Society of Chemical Industry.

Microbial and Quality Attributes of Beef Steaks under High-CO2 Packaging: Emitter Pads versus Gas Flushing.

Over 21 days of cold storage, the quality and microbial composition of beef steaks in response to different high-CO2 packaging conditions achieved by flushing gas mixtures or embedding gas emitters into the packages were studied. The results revealed that the high levels of CO2, achieved by either the gas flushing or the CO2 emitter pads, effectively controlled the number of aerobic counts. The headspace CO2 increased quickly in response to using the CO2 emitter pads, and the meat samples presented different pH levels and surface color (a* and b*) values compared to the samples packaged with the gas flushing technique. Excessive accumulation of gas in the packages that contained CO2 emitters resulted in package swelling and higher levels of drip loss. The longest overall quality and attractive red color of the meat samples were observed when the packages were initially flushed with the headspace gas mixture containing high levels of oxygen. Overall, using CO2 emitters for meat packaging can be suggested when a topfilm with proper permeability to O2 and CO2 gases is used to regulate the internal CO2/O2 and gas/product ratios.

Ultrasonic potential in maintaining the quality and reducing the microbial load of minimally processed pomegranate.

Difficulty of Pomegranate fruit peeling and arils separation are the main motivations of progressive ready-to-eat pomegranate fresh arils industry. Also, extracted pomegranate arils are highly perishable due to water loss and microbial contamination expose. The aim of the current work was then to evaluate the effect of ultrasound for 15 and 30 min on maintenance of bioactive compounds and microbial load reduction of pomegranate arils cv. Rabbab. Treated arils were kept at 5 °C and analyzed during 15 days of storage. The most and least weight loss of arils obtained in control and 30 min treated samples, respectively. After 12 days of storage, all samples were decayed except those treated for 15 and 30 min. The ultrasound treatment significantly prevented degradation of anthocyanin and ascorbic acid compounds. Total phenol and antioxidant activity decreased during storage. At the end of storage, the most total phenol content (3898.6 mg GAE L-1) was found in arils treated for 30 min whereas the most anthocyanin (91.93 mg L-1), total antioxidant activity (82.65%), and ascorbic acid (2.53 mg L-1) were found in arils treated for 15 min. Ultrasound treated arils had lower microbial load (total mesophilic bacteria in control and 30-min treated samples) in each stage during storage. At the end of storage, the microbial load in treated and control arils was 0.7 and 0.2 Log CFU g-1, respectively). Overall, ultrasound treatment effectively reduced weight loss and preserved bioactive compounds during storage.