Use of bio-protective cultures to improve the shelf-life and the sensorial characteristics of commercial hamburgers

The effect of nano/microparticles of bee pollen on the shelf life of high-fat cooked sausage during refrigerated storage

Sausage is susceptible to oxidative changes in lipids and microbial spoilage due to the presence of water, fat, protein, and vitamins. Bee pollen (BP) as a source of potential antioxidants and antibacterial compounds can effectively prevent lipid peroxidation and microbial spoilage in meat products. The aim of the present study was to investigate the antibacterial and antioxidant activities of BP and the effects of nano/microparticles of bee pollen extract (n/m BP) at a concentration of 125 and 250 mg/100 g meat on the oxidative stability and microbial growth of high-fat sausage during 30 days of storage at 4°C. The formation of BP particles in the nano/micro range was confirmed by scanning electron microscopy. High concentrations of total phenolic compounds (28.26 ± 0.10 mg GAE/g BP) with antioxidant activity (EC50 = 5.4 ± 0.07 mg/mL) were detected in BP. Based on the microdilution assay, the minimum inhibitory concentration of n/m BP for all test bacteria was 1000 (μg/mL) and the minimum bactericidal concentration of n/m BP was 2000 (μg/mL) for Staphylococcus aureus and Bacillus cereus and 4000 (μg/mL) for Escherichia coli and Pseudomonas aeruginosa. The n/m BP treatment (250 mg/100 g meat) showed a higher pH value (p < .05) and lower TBARS values (p < .05) than the ascorbic acid treatment (100 mg/100 g meat) and the control during the storage period. The microbial analysis showed that the addition of n/m BP led to a significant decrease (p < .05) in the total bacterial count, coliforms, S. aureus, and fungal population compared to the other samples. The results show that the addition of n/m BP (125 mg/100 g) can improve the texture, taste, and overall acceptability of the sausage compared to the control sample. In conclusion, this study suggests that BP can replace synthetic antioxidants in high-fat sausages at the nano/microparticle level.

The biological effect of a beef-derived Latilactobacillus sakei on beef steaks during chilled storage

The aim of this study was to investigate the biological inhibiting effect of a beef-derived Latilactobacillus sakei (RS-25) on the spoilage of beef steaks in overwrapped packaging during the 12 days of storage at 4°C. Beef quality as well as microbial indicators were determined at different intervals during the storage after the inoculation of RS-25 at the 6 log CFU/g, and the high-throughput sequencing was applied to investigate the changes of microbial community structure during the storage. The inoculation of RS-25 on beef had no effect (p > .05) on pH, TBARS, and TVB-N during storage indicating the weak effect of such strain on the eat quality. Furthermore, the rise of L* and the delayed decline of a* and b* reveal the protection effect of RS-25 on the meat color. RS-25 reduced the re-contaminated Salmonella typhimurium by 1.16 log CFU/g (p < .01), and the growth of Brochothrix thermosphacta was also inhibited but no inhibition was found on the Pseudomonas spp. at the first 6 days of storage. The inhibiting effect of RS-25 was covered by the rapid growth of other microorganism during the following 6 days of storage. Consistent with the microbial counts results, high-throughput sequencing analysis confirmed that the inoculated L. sakei RS-25 was dominant at first 6 days, and then replaced by Pseudomonas spp. The findings obtained from the current study may provide basic information for the further application of bioprotective bacteria in preservation of beef steaks in the overwrapped packaging.

Processing interventions for enhanced microbiological safety of beef carcasses and beef products: A review

Chilled beef is inevitably contaminated with microorganisms, starting from the very beginning of the slaughter line. A lot of studies have aimed to improve meat safety and extend the shelf life of chilled beef, of which some have focused on improving the decontamination effects using traditional decontamination interventions, and others have investigated newer technologies and methods, that offer greater energy efficiency, lower environmental impacts, and better assurances for the decontamination of beef carcasses and cuts. To inform industry, there is an urgent need to review these interventions, analyze the merits and demerits of each technology, and provide insight into 'best practice' to preserve microbial safety and beef quality. In this review, the strategies and procedures used to inhibit the growth of microorganisms on beef, from slaughter to storage, have been critiqued. Critical aspects, where there is a lack of data, have been highlighted to help guide future research. It is also acknowledge that different intervention programs for microbiological safety have different applications, dependent on the initial microbial load, the type of infrastructures, and different stages of beef processing.

Improving the Shelf-Life of Fish Burgers Made with a Mix of Sea Bass and Sea Bream Meat by Bioprotective Cultures

Seafood products are one of the most perishable foods, and their shelf life is limited by enzymatic and microbial spoilage. Developing methods to extend the shelf life of fresh fish could reduce food waste in the fishery industry, retail stores, and private households. In recent decades, the application of lactic acid bacteria (LAB) as bioprotective cultures has become a promising tool. In this study, we evaluated the use of four starter cultures, previously selected for their properties as bioprotective agents, for sea bass and sea bream burgers biopreservation. Starter cultures impacted the microbial populations, biochemical parameters (pH, TVB-N), and sensory properties of fish burgers, during 10 days of storage at 4 °C and then 20 days at 8 °C in modified atmosphere packaging (MAP). Also, storage time influenced the microbial and physicochemical characteristics of all the tested samples, except for TVB-N values, which were significantly higher in the uninoculated burgers. The volatilome changed in the different treatments, and in particular, the samples supplemented with starter presented a profile that described their rapid growth and colonization, with the production of typical molecules derived from their metabolism. The addition of bioprotective cultures avoided bloating spoilage and improved the sensory parameters of the burgers. The shelf life of the fish burgers supplemented with starter cultures could be extended up to 12 days.

Effect of the Application of a Green Preservative Strategy on Minced Meat Products: Antimicrobial Efficacy of Olive Mill Wastewater Polyphenolic Extract in Improving Beef Burger Shelf-Life

The mincing process of raw meat favors microbial spoilage as well as chemical and enzymatic oxidation processes. In order to limit this degradative process, preservatives are routinely added to minced meat products. The role of olive mill wastewater polyphenolic extract as a replacement for synthetic preservatives in beef burger was assessed. The antioxidant capacity of the extract experimentally added to beef burger was evaluated using the oxygen radical absorbance capacity method (ORAC_FL) to assess the shelf-life, while the lipid oxidation was measured by thiobarbituric reactive substance (TBAR) determination. The antimicrobial activity was assayed by means of classical methods and predictive microbiology. The experimental addition of polyphenolic extract led to 62% lower lipid oxidation and 58% higher antioxidant capacity; it also successfully modulated spoilage microbial populations with an average growth reduction of 15% on day 7. Results indicate that olive mill wastewater polyphenolic extracts could be added to raw ground beef meat to act as natural antioxidants and to modulate microbial growth.

Natural alternatives for processed meat: Legislation, markets, consumers, opportunities and challenges

Consumers' interest in food with less and/or free from synthetic additives has increased considerably in recent years. In this context, researchers and industries have concentrated efforts on developing alternatives to these compounds. Replacing synthetic additives in meat products is a challenge, given their importance for sensory characteristics and food safety. Complementary technologies combined with the replacement and/or reduction of synthetic additives (hurdle technologies) has been studied focusing on the protection and extension of the shelf life of meat products. This review reports alternatives for replacing and/or reducing the use of synthetic additives in meat derivatives, aiming at the development of more natural and simpler meat products, familiar to consumers and considered clean labels.

Inoculation of Lactobacillus sakei on Quality Traits of Dry Fermented Sausages

In this study, fermented sausage prepared by inoculating different strains of Lactobacillus sakei was assessed for their physiochemical, microbiological, and textural characteristics during fermentation and ripening. Five treatments were prepared: Control (commercial starter culture, C), L. sakei Korean Collection for Type Cultures (KCTC)-3802 (S1), L. sakei KCTC-3598 (S2), L. sakei KCTC-5053 (S3), and L. sakei KCTC-3603 (S4). The different strains of L. sakei did not show substantial differences (P>0.05) in pH values for dry fermented sausages at the end of the ripening period. Water activity (aw) values for all treatments were below 0.85 (P<0.05). Total viable count at the end of the study decreased in all L. sakei starter culture inoculated fermented sausages as S3> S2> S1> S4. High values of lactic acid bacteria (LAB) count and hardness were observed in the S2 batch as compared to other L. sakei inoculated treatments at the end of ripening (21st day). S3 inoculated with L. sakei strain exhibited significantly (P<0.05) higher value of a* (redness). A significant difference (P<0.05) in thiobarbituric acid reactive substances was exhibited in the following order: S4> S2> S1> S3> C. This study suggests that inoculation of S3 (L. sakei KCTC-5053) strain can improve the red color and reduce lipid oxidation while S2 enhances better microbiological quality as LAB. Incorporation of S3 and S2 strains accordingly can be helpful to enhance the quality of dry fermented sausages.

Evaluation of the potential of protective cultures to extend the microbial shelf-life of chilled lamb meat

The use of protective cultures to inhibit spoilage bacteria is a promising natural preservation technique to extend the shelf-life of fresh meat. This study evaluated the effectiveness of six food-grade protective cultures (containing different combinations of Lactobacillus sakei, Pediococcus pentosaceus, Staphylococcus xylosus, and Staphylococcus carnosus) on naturally contaminated chill-stored (4 °C) lamb meat in different packaging systems. Only slight reductions of common meat spoilage bacteria Brochothrix thermosphacta, Pseudomonas spp., and Enterobacteriaceae were observed in culture-treated samples stored in modified atmosphere packaging (80% O₂:20% CO₂). Greater inhibitory effects were found in vacuum-packed lamb, with mixed cultures containing either L. sakei, S. carnosus, and S. xylosus or S. carnosus and L. sakei causing the most significant reductions. Protective cultures did not adversely affect meat color or pH. This study demonstrated the potential of protective cultures comprising lactic acid bacteria and coagulase-negative staphylococci in controlling microbial spoilage of lamb and, by inference, other types of meat as a natural solution for shelf-life extension.

Microbial biopreservatives for controlling the spoilage of beef and lamb meat: their application and effects on meat quality

Biopreservation is a recognized natural method for controlling the growth of undesirable bacteria on fresh meat. It offers the potential to inhibit spoilage bacteria and extend meat shelf-life, but this aspect has been much less studied compared to using the approach to target pathogenic bacteria. This review provides comprehensive information on the application of biopreservatives of microbial origin, mainly bacteriocins and protective cultures, in relation to bacterial spoilage of beef and lamb meat. The sensory effect of these biopreservatives, an aspect that often receives less attention in microbiological studies, is also reviewed. Microbial biopreservatives were found to be able to retard the growth of the major meat spoilage bacteria, Brochothrix thermosphacta, Pseudomonas spp., and Enterobacteriaceae. Their addition did not have any discernible negative impact on the sensory properties of meat, whether assessed by human sensory panels or instrumental and chemical analyses. Although results are promising, the concept of biopreservation for controlling spoilage bacteria on fresh meat is still in its infancy. Studies in this area are still lacking, especially for lamb. Biopreservatives need more testing under conditions representative of commercial meat production, along with studies of any possible sensory effects, in order to validate their potential for large-scale industrial applications.

Hydrogelled emulsion from chia and linseed oils: A promising strategy to produce low-fat burgers with a healthier lipid profile

Burgers (20% pork back fat) were produced with the replacement of 0, 20, 40, 60, 80, and 100% of pork back fat by hydrogelled emulsion (HE) from chia and linseed oils. No changes (P > .05) were observed for the moisture retention, diameter reduction, and cooking loss of the treatments, with a significant increase in the lipid retention (P < .05). Hardness increased (P < .05) with increasing the lipid replacement level, and a significant color difference (ΔE) was detected between the treatments and the control. In addition to reducing animal fat, a healthier fatty acid profile was reached after the lipid reformulation of the burgers, thus allowing the burgers to be labeled with health claims. The sensory tests (acceptance and Check-All-That-Apply) indicated that it is possible to replace up to 60% of pork back fat by HE.

Lipid Oxidation, Color Changes, and Microbiological Quality of Frozen Beef Burgers Incorporated with Shirazi Thyme, Cinnamon, and Rosemary Extracts

In this study, the oxidative stability of beef burgers incorporated with Shirazi thyme, cinnamon, and rosemary extracts was compared with that of BHT-incorporated and antioxidant-free samples. The chemical composition, TBARS, metmyoglobin, pH, color, and microbial and sensory characteristics were evaluated during storage at −18°C for 2 months. The results indicated that Shirazi thyme and cinnamon extracts did not change the colorimetric properties significantly (P<0.05). Incorporating natural antioxidants led to a significant (P<0.05) reduction in TBARS (36.58–46.34%) and metmyoglobin (16.25–18.47%) as compared to control. Except for the control sample, total microbial counts of burgers were lower than the maximum allowed limit. Burgers formulated with Shirazi thyme revealed the lowest amount of total count. Regarding the sensory characteristics, the overall acceptability of different samples decreased in the order of cinnamon > BHT > Shirazi thyme > rosemary > control. Finally, the results showed that these plant extracts can be utilized as an alternative to synthetic antioxidants in formulation of burgers.

Lactic acid bacteria as protective cultures in fermented pork meat to prevent Clostridium spp. growth

In meat fermented foods, Clostridium spp. growth is kept under control by the addition of nitrite. The growing request of consumers for safer products has led to consider alternative bio-based approaches, the use of protective cultures being one of them. This work is aimed at checking the possibility of using two Lactobacillus spp. strains as protective cultures against Clostridium spp. in pork ground meat for fermented salami preparation. Both Lactobacillus strains displayed anti-clostridia activity in vitro using the spot agar test and after co-culturing them in liquid medium with each Clostridium strain. Only one of them, however, namely L. plantarum PCS20, was capable of effectively surviving in ground meat and of performing anti-microbial activity in carnis in a challenge test where meat was inoculated with the Clostridium strain. Therefore, this work pointed out that protective cultures can be a feasible approach for nitrite reduction in fermented meat products.