Effect of High-Pressure Processing on the Microbial Quality throughout the Shelf Life of Vacuum-Packed Sliced Ham and Frankfurters

Protective effects of Bacillus velezensis on texture, physicochemical properties, and lipid oxidation of grass carp fillets during repeated freeze-thaw cycles

BACKGROUND

Probiotics have excellent antioxidant and antibacterial effects and are also considered to be promising natural biological preservatives. This study examined the freeze-thaw stability of the antioxidant and antibacterial activity of probiotic Bacillus velezensis PJP10, and evaluated the effect of different concentrations of PJP10 (106, 107, and 108 CFU mL-1) on microbial growth, textural characteristics, physicochemical properties, and lipid oxidation of grass carp fillets during repeated freeze-thaw cycles.

RESULTS

Freeze-thaw cycles had little effect on the antioxidant and antibacterial stability of PJP10. Treatment with the PJP10 strain slowed effectively the increase in Aeromonas spp. counts (ASC), pH, total volatile basal nitrogen (TVB-N), and thiobarbituric acid (TBA) values of the freeze-thaw fish fillets. It maintained the textural quality of fillets, inhibiting the reduction of hardness, springiness, gumminess, cohesiveness, chewiness, and resilience values, and reduced lipid oxidation, as evidenced by decreased carbonyl values and conjugated diene values after multiple freeze-thaw cycles.

CONCLUSION

Probiotic B. velezensis PJP10 had protective effects on microbiological, textural, and physicochemical properties, and lipid oxidation of grass carp fillets during repeated freeze-thaw storage, suggesting a potential application of this strain in the freeze-thaw preservation of freshwater fish. © 2024 Society of Chemical Industry.

Microbial Control in the Processing of Low-Temperature Meat Products: Non-Thermal Sterilization and Natural Antimicrobials

The safety and health of food have been persistent concerns, particularly about meat products. Low-temperature meat products refer to those that are processed at lower temperatures. Meat, rich in proteins and other nutrients, is highly susceptible to microbial contamination, leading to spoilage, particularly when processed at lower temperatures that increase storage and transportation requirements. In response to the limitations of conventional preservation methods, such as heat treatment and chemical bacteriostats, emerging preservation technologies are increasingly being adopted. These technologies aim to mitigate the negative effects of microorganisms on meat products. Non-thermal technologies and biotechnological approaches, which are low in energy consumption and energy efficiency, are becoming more prevalent. Non-thermal sterilization technology is widely applied in various food products. It maintains the original quality of food, enhances food safety, reduces energy consumption, and improves production efficiency. Biocides are extensively used in the antibacterial field owing to their high efficiency, low toxicity, and long-lasting properties. Both non-thermal sterilization technology and biocides can ensure food safety, extend the shelf life of food products, improve food quality, meet consumers' demand for natural and healthy food, enhance market competitiveness, and play a positive role in promoting the sustainable development of the food industry. This paper provides a comprehensive review of the specific applications of biocides and non-thermal sterilization methods in food, highlighting the control parameters and their effects on microbes during low-temperature meat processing, to supply pertinent researchers with theoretical references.

Macroalgae-Fortified Sausages: Nutritional and Quality Aspects Influenced by Non-Thermal High-Pressure Processing

The present work evaluated the nutritional impact of macroalgae flours used as new ingredients in fermented sausages and the feasibility of using high-pressure processing (HPP) as a non-thermal pasteurization methodology to keep the quality attributes of the new food products. A commercial macroalgae mix was used in the formulation of new macroalgae-fortified meat frankfurter sausages (F-MFS), macroalgae-fortified vegetable frankfurter sausages (F-VFS) and in macroalgae-fortified traditional Portuguese sausage "chouriço" (F-TPS), overall incrementing the contents of Mg, K, Ca, Mn and Fe and decreasing the Na/K ratio. The application of HPP allowed extending the shelf-life of frankfurters by about 3-fold and improved the safety of "chouriço" along 180 days of storage, keeping its microbial load below the detection limit. The prevention of microbial growth in F-MFS and F-VFS was accompanied by pH stability of the products. In addition, no significant detriment on surface color and fatty acids was observed between pressurized and non-pressurized sausages, allowing consolidating the suitability of HPP in seaweed-fortified fermented sausages.

Valorization of Carob Fruit Residues for the Preparation of Novel Bi-Functional Polyphenolic Coating for Food Packaging Applications

The food industry has become interested in the development of innovative biomaterials with antioxidant and antimicrobial properties. Although several biopolymers have been evaluated for food packaging, the use of polyphenolic coatings has been unexplored. The purpose of this work was to develop an antioxidant and antimicrobial coating for food packaging through the polymerization of carob phenolics. At first, the polyphenolic coatings were deposited in glass surfaces polymerizing different concentrations of carob extracts (2 and 4 mg mL⁻¹) at three pH values (7, 8 and 9). Results demonstrated that the coating produced at pH 8 and at a concentration of 4 mg mL⁻¹ had the most potent antioxidant and antimicrobial potential. Then, the coating was applied directly on the salmon fillet (coating) and on the plastic container (active packaging). Peroxide and thiobarbituric acid-reactive substances (TBARS) methods were used to measure the potency to inhibit lipid oxidation in salmon fillets. Furthermore, the anti-Listeria activity of coatings was also assessed. Results showed a significant decrease of lipid oxidation during cold storage of salmon fillets for both treatments; the superiority of applied coating directly on the salmon fillets was also highlighted. Regarding the antimicrobial potency, the polyphenolic coating depleted the growth of Listeria monocytogenes after 10 days storage; while the active packaging had no effect on Listeria monocytogenes. Overall, we describe the use of low-cost carob polyphenols as precursors for the formation of bifunctional coatings with promising applications in food packaging.