Effects of Preservatives, Processing Technologies, Packaging Systems and Bioprotective Agents on the Microbiome of Foods

A special issue of Foods (ISSN 2304-8158). This special issue belongs to the section "Food Microbiology".

Deadline for manuscript submissions: closed (24 July 2023) | Viewed by 8955

Special Issue Editor


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Guest Editor
School of Food and Health, Beijing Technology and Business University, Beijing10048, China
Interests: food microbiology; foodborne pathogenic bacteria; natural food preservatives

Special Issue Information

Dear Colleagues,

The microbiome of foods is very diverse, and may have both beneficial and deleterious effects on food quality and safety, comprising fermentative, probiotic, spoilage, and pathogenic bacteria, moulds, yeasts, and other microorganisms. The survival and growth of these diverse microorganisms is affected by food processing technologies, the use of preservatives, food packaging systems, and bioprotectants. An understanding of the effects of preservatives, bioprotectants, processes, and packaging systems on food microbiomes is critical for ensuring food quality and safety. Natural preservatives have shown high potential to inhibit the growth of foodborne pathogens and spoilage bacteria, but their effects in real-world application have not been fully evaluated in food products. Some physical processing techniques, including high hydrostatic pressure, ultrasonic, microwave, radiation, supercritical carbon dioxide, etc., have gained increasing interest as potential non-thermal techniques for ready-to-eat post-processed products. How to choose scientific and reasonable physical technology for different food processes is a question that remains to be solved. In recent years, the development of novel active packaging and nanotechnology has not only increased the shelf life of foods, but also their safety and quality. The release kinetics of anti-microbial agents used for the matrices of food packaging has not been studied completely. New potential approaches to prolonging the shelf life of fresh or fermented products are developed using bioprotective agents, which consist of the use of natural or controlled microbiota or natural antimicrobials, through modulating the food microbiome. The effectiveness of bioprotective agents in maintaining product quality during proper or abuse temperature storage periods still needs to be confirmed.

Prof. Dr. Guorong Liu
Guest Editor

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Keywords

  • preservatives
  • processing technologies
  • packaging systems
  • bioprotective agents
  • microbiome
  • food quality and safety

Published Papers (4 papers)

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21 pages, 3838 KiB  
Article
Microbial Profiling of Biltong Processing Using Culture-Dependent and Culture-Independent Microbiome Analysis
by Caitlin Karolenko, Udaya DeSilva and Peter M. Muriana
Foods 2023, 12(4), 844; https://doi.org/10.3390/foods12040844 - 16 Feb 2023
Cited by 2 | Viewed by 1693
Abstract
Biltong is a South African air-dried beef product that does not have a heat lethality step, but rather relies on marinade chemistry (low pH from vinegar, ~2% salt, spices/pepper) in combination with drying at ambient temperature and low humidity to achieve microbial reduction [...] Read more.
Biltong is a South African air-dried beef product that does not have a heat lethality step, but rather relies on marinade chemistry (low pH from vinegar, ~2% salt, spices/pepper) in combination with drying at ambient temperature and low humidity to achieve microbial reduction during processing. Culture-dependent and culture-independent microbiome methodologies were used to determine the changes in the microbial community at each step during biltong processing through 8 days of drying. Culture-dependent analysis was conducted using agar-based methods to recover viable bacteria from each step in the biltong process that were identified with 16S rRNA PCR, sequencing, and BLAST searching of the NCBI nucleotide database. DNA was extracted from samples taken from the laboratory meat processing environment, biltong marinade, and beef samples at three stages of processing (post-marinade, day 4, and day 8). In all, 87 samples collected from two biltong trials with beef obtained from each of three separate meat processors (n = six trials) were amplified, sequenced with Illumina HiSeq, and evaluated with bioinformatic analysis for a culture-independent approach. Both culture-dependent and independent methodologies show a more diverse population of bacteria present on the vacuum-packaged chilled raw beef that reduces in diversity during biltong processing. The main genera present after processing were identified as Latilactobacillus sp., Lactococcus sp., and Carnobacterium sp. The high prevalence of these organisms is consistent with extended cold-storage of vacuum-packaged beef (from packers, to wholesalers, to end users), growth of psychrotrophs at refrigeration temperatures (Latilactobacillus sp., Carnobacterium sp.), and survival during biltong processing (Latilactobacillus sakei). The presence of these organisms on raw beef and their growth during conditions of beef storage appears to ‘front-load’ the raw beef with non-pathogenic organisms that are present at high levels leading into biltong processing. As shown in our prior study on the use of surrogate organisms, L. sakei is resistant to the biltong process (i.e., 2-log reduction), whereas Carnobacterium sp. demonstrated a 5-log reduction in the process; the recovery of either psychrotroph after biltong processing may be dependent on which was more prevalent on the raw beef. This phenomenon of psychrotrophic bloom during refrigerated storage of raw beef may result in a natural microbial suppression of mesophilic foodborne pathogens that are further reduced during biltong processing and contributes to the safety of this type of air-dried beef. Full article
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23 pages, 2624 KiB  
Article
Effect of Nanoemulsion Containing Enterocin GR17 and Cinnamaldehyde on Microbiological, Physicochemical and Sensory Properties and Shelf Life of Liquid-Smoked Salmon Fillets
by Jiaojiao Duan, Rong Nie, Jing Du, Haoxuan Sun and Guorong Liu
Foods 2023, 12(1), 78; https://doi.org/10.3390/foods12010078 - 23 Dec 2022
Cited by 3 | Viewed by 1503
Abstract
The spoilage of liquid-smoked salmon represented a serious restriction for shelf life, due to the loss of taste, smell, color and consistency in product quality. The objective of this study was to investigate the feasibility of applying a nanoemulsion delivery system co-encapsulated enterocin [...] Read more.
The spoilage of liquid-smoked salmon represented a serious restriction for shelf life, due to the loss of taste, smell, color and consistency in product quality. The objective of this study was to investigate the feasibility of applying a nanoemulsion delivery system co-encapsulated enterocin Gr17 and essential oils (EOs) to the refrigerated storage of liquid-smoked salmon. The synergistic inhibiting effects of enterocin Gr17 and EOs were evaluated, a nanoemulsion delivery system with the optimal combination was developed, and the evolution of the microbiological, physicochemical, and sensory properties of liquid-smoked salmon fillets were analyzed during a 49-day period of refrigerated storage. The results showed that the combination of enterocin Gr17 and cinnamaldehyde essential oil (CEO) displayed the strongest synergistic inhibiting effect on foodborne pathogens. A nanoemulsion system incorporating enterocin Gr17 and CEO was successfully developed and presented a broad spectrum of activity against most of the tested bacteria. A nanoemulsion system incorporating enterocin Gr17 and CEO (CO-NE) could significantly inhibit the growth of microflora, suppress the accumulation of total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substance (TBARS), and maintain better color, texture, and sensory profiles during smoked salmon storage at 4 °C. Overall, from a microbiological, physicochemical, and sensory point of view, the CO-NE treatment could extend the shelf life to 42 days and maintain the relatively low TVB-N value (≤15.38 mg/100 g), TBARS value (≤2.51 mg MDA/kg), as well as a relatively high sensory score (≥5.83) during the whole storage period. Hence, a nanoemulsion system incorporating enterocin Gr17 and CEO could be a promising bio-preservative technology and alternative to the conventional processes used for improving the safety and quality of chilled liquid-smoked salmon. Full article
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12 pages, 5738 KiB  
Article
Determining the Role of UTP-Glucose-1-Phosphate Uridylyltransferase (GalU) in Improving the Resistance of Lactobacillus acidophilus NCFM to Freeze-Drying
by Zhidan Zeng, Xiaoqun Zeng, Yuxing Guo, Zhen Wu, Zhendong Cai and Daodong Pan
Foods 2022, 11(12), 1719; https://doi.org/10.3390/foods11121719 - 12 Jun 2022
Cited by 3 | Viewed by 2152
Abstract
Lactobacillus acidophilus NCFM is widely used in the fermentation industry; using it as a freeze-dried powder can greatly reduce the costs associated with packaging and transportation, and even prolong the storage period. Previously published research has reported that the expression of galU (EC: [...] Read more.
Lactobacillus acidophilus NCFM is widely used in the fermentation industry; using it as a freeze-dried powder can greatly reduce the costs associated with packaging and transportation, and even prolong the storage period. Previously published research has reported that the expression of galU (EC: 2.7.7.9) is significantly increased as a result of freezing and drying. Herein, we aimed to explore how galU plays an important role in improving the resistance of Lactobacillus acidophilus NCFM to freeze-drying. For this study, galU was first knocked out and then re-expressed in L. acidophilus NCFM to functionally characterize its role in the pertinent metabolic pathways. The knockout strain ΔgalU showed lactose/galactose deficiency and displayed irregular cell morphology, shortened cell length, thin and rough capsules, and abnormal cell division, and the progeny could not be separated. In the re-expression strain pgalU, these inhibited pathways were restored; moreover, the pgalU cells showed a strengthened cell wall and capsule, which enhanced their resistance to adverse environments. The pgalU cells showed GalU activity that was 229% higher than that shown by the wild-type strain, and the freeze-drying survival rate was 84%, this being 4.7 times higher than that of the wild-type strain. To summarize, expression of the galU gene can significantly enhance gene expression in galactose metabolic pathway and make the strain form a stronger cell wall and cell capsule and enhance the resistance of the bacteria to an adverse external environment, to improve the freeze-drying survival rate of L. acidophilus NCFM. Full article
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14 pages, 2852 KiB  
Technical Note
Quality and Shelf-Life Evaluation of Fresh Beef Stored in Smart Packaging
by Andi Dirpan and Serli Hatul Hidayat
Foods 2023, 12(2), 396; https://doi.org/10.3390/foods12020396 - 13 Jan 2023
Cited by 4 | Viewed by 2933
Abstract
Beef is a perishable food product susceptible to deterioration due to microbial growth. Therefore, this study aimed to ascertain how active and intelligent packaging performs by tracking the change in the quality of fresh beef stored at low temperatures. The intelligent packaging method [...] Read more.
Beef is a perishable food product susceptible to deterioration due to microbial growth. Therefore, this study aimed to ascertain how active and intelligent packaging performs by tracking the change in the quality of fresh beef stored at low temperatures. The intelligent packaging method employed indicators with solutions of Bromo Phenol Blue (BPB) and Phenol Red (PR) to monitor the change in beef quality. Additionally, active packaging used garlic extract with various concentrations at 0%, 15%, and 20% to maintain the quality of beef packaged at 10 °C temperatures. The findings illustrated that a packaging indicator label can be implemented to monitor the change in the quality of fresh beef stored at 10 °C temperatures. This was signified by a change in the indicator color from dark yellow to orange and red, fading to purple. Meanwhile, observations on active packaging demonstrated that 15% and 20% of garlic extract were the most effective approaches for preserving beef quality. The correlation level of indicator label color analysis and the effectiveness of active packaging with all beef spoilage metrics demonstrated a positive correlation in preserving quality and identifying the degree of beef damage. Therefore, these active and intelligent packaging indicators can be applied to monitor and retain the quality of packaged beef. Full article
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