Dominant Spoilage Bacteria Research Articles

Effects of different storage temperatures on microbial spoilage and bacterial community structure of fresh beef by high-throughput sequencing technology

Comparsion of the effects of the chilling (4 ºC), superchilling (-2 ºC) and frozen (-18 ºC) storage on microbial spoilage and bacterial community structure of fresh beef was evaluated by high-throughput sequencing technology in this study. The results indicated that storage temperature can significantly affect the degree of microbial spoilage and bacterial community structure of fresh beef during storage. At the species level, the primary dominant bacterial species in beef samples was Pseudomonas fragi with relative abundance of 37.78% followed by Myroides phaeus and Brochothrix thermosphacta with 10.95% and 4.64%, respectively, at the beginning of storage. Both superchilling and frozen storage can effectively inhibit the growth of P. fragi, while the chilling storage failed to demonstrate strong inhibition for growth of P. fragi. Similar result was found for Myroides phaeus. The chilling, superchilling and frozen storage can not effectively inhibit the growth of Brochothrix thermosphacta and Acinetobacter johnsonii. The difference of microbial spoilage in beef stored in three kinds of storage may be related to the difference of the bacterial community structure and the formation of dominant spoilage bacteria. These results revealed that superchilling and frozen storage can effectively inhibit the formation of dominant spoilage bacteria, resulting in a good freshness preservation.

Changes in the microbiota of a vacuum-packed cooked bass product and the effects of cobalt irradiation on its quality during storage

This study investigates changes in the microbiota of vacuum-packed cooked bass (Micropterus salmoides), including the effects of different doses of 60Co-γ irradiation (0, 1, 3, and 5 kGy) on muscle quality, during storage at 4 °C (0–15 days). Analyses for other indicators like the total bacterial colony counts and myofibrillar protein concentration were carried out. 16SrDNA high-throughput sequencing results showed that Stenotrophomonas maltophilia had the highest relative abundance in bass after storage. Additionally, the total bacterial colony counts and total volatile basic nitrogen (TVB-N) content of the irradiated samples were within the standard limits after day 15. During 0–6 days of storage, 3 kGy irradiation increased the myofibrillar protein concentration and the water-holding capacity of the fish compared with other doses. However, 3 kGy irradiation had less influence on the surface hydrophobicity of myofibrillar proteins than 5 kGy irradiation. Overall, Stenotrophomonas maltophilia was the dominant spoilage bacteria in bass, and 3 kGy irradiation treatment effectively inhibited microbial proliferation and muscle quality deterioration during storage at 4 °C. Moreover, the optimal storage time for bass products after 3 kGy irradiation treatment was 6 days. This provides a basis for improving bass quality during storage and promoting the application of irradiation technology.

Dynamics of microbial communities of fresh broad bean pods and screening of biological preservatives

This study aimed to determine the dynamics of the microbiome of fresh broad bean pods stored at 10 °C and select targeted and efficient biological preservatives. Culture-dependent 16S rRNA and ITS (Internal Transcribed Spacer) sequencing combined with high-throughput sequencing (HTS) were used to analyze the microbial diversity. The biological preservatives were chosen by antimicrobial analysis and their effects on maintaining freshness. The bacterial and fungal community richness decreased with prolonged storage. The microbial diversity of samples collected on day 0 was clearly distinct from that of samples collected on day 30. The dominant spoilage bacteria were Pseudomonas, Pantoea, Stenotrophomonas and Flavobacterium and the dominant spoilage fungi Pseudogymnoascus, Cladosporium, and Beauveria. Clove essential oil (0.5%) and β-glucan from naked barley (1%) were selected as targeted and efficient biological preservatives for fresh broad bean pods. The results provide a basis for developing technology to prolong the shelf-life of fresh broad bean pods.

Mathematical Modeling of the Effects of Temperature and Modified Atmosphere Packaging on the Growth Kinetics of Pseudomonas Lundensis and Shewanella Putrefaciens in Chilled Chicken.

The effects of modified atmosphere packaging (MAP) on the growth and spoilage characteristics of Pseudomonas lundensis LD1 and Shewanella putrefaciens SP1 in chilled chicken at 0–10 °C were studied. MAP inhibited microbial growth, TVB-N synthesis, and lipid oxidation. The inhibitory effect of MAP became more significant as the temperature decreased. The kinetic models to describe the growth of P. lundensis LD1 and S. putrefaciens SP1 at 0–10 °C were also established to fit the primary model Gompertz and the secondary model Ratkowsky. The models had a high degree of fit to describe the growth of dominant spoilage bacteria in chilled chicken. The observed numbers of P. lundensis LD1 and S. putrefaciens SP1 at 2 °C were compared with the predicted numbers, and the accuracy factor and bias factor ranged from 0.93 to 1.14. These results indicated that the two models could help predict the growth of P. lundensis and S. putrefaciens in chilled chicken at 0–10 °C. The analyzed models provide fast and cost-effective alternatives to replace traditional culturing methods to assess the influence of temperature and MAP on the shelf life of meat.

Influence of the combination of cinnamon essential oil nanoemulsions and epsilon-polylysine on microbial community and quality of pork during refrigerated period and radio frequency cooking

Pork preservation and cooking are common processes in food production. This study analyzed the influence of cinnamon essential oil nanoemulsions (CEON), ε-polylysine (ε-PL) and CEON/ε-PL on microbial community and quality of pork during refrigerated storage and radio frequency (RF) cooking. Results showed that a stable CEON was prepared with soybean lecithin (oil: lecithin = 1:1 w/w). CEON and ε-PL inhibited the growth of total bacteria counts (TBC) of raw pork, and caused Salmonella reduction at refrigerated storage of 12 d. Photobacterium and Pseudomonas were dominant spoilage bacteria of raw pork during refrigerated period. The 0.25 % CEON and 0.125 % CEON + 0.25 % ε-PL had good antimicrobial effects against Photobacterium while 0.5 % ε-PL had a small effect. Pork treated by CEON and CEON/ε-PL had better freshness than control and ε-PL treated samples. RF cooking lowered cooking time compared to water bath cooking at 80 °C and a similar quality of cooked pork was observed. CEON/ε-PL promoted Salmonella and TBC inactivation during RF cooking. TVB-N content, pH, cooking loss and appearance of RF cooked pork were not influenced by the addition of CEON/ε-PL, but the odor was slightly affected. The hardness, springiness and chewiness were enhanced by the addition of CEON/ε-PL. The results revealed that CEON/ε-PL could be used in raw pork preservation and promote bacteria inactivation during RF cooking.

The Effect of Chitosan Treatment on the Microbial Diversity of Cold-Stored Macrobrachium rosenbergii

ABSTRACT The objective of the study was to evaluate the effect of chitosan on the pre-servation of Macrobrachium rosenbergii during cold storage. M. rosenbergii samples were divided into control and experimental groups and immersed in pure water and 1.5% chitosan solutions, respectively, followed by storage at 4°C Changes were measured in tissue sensory scores, pH (hydrogen potential), total volatile base nitrogen (TVB-N), total viable count (TVC), and K values. Further, 16S ribosomal ribonucleic acid (rRNA) sequencing was used to study the effects of chitosan on microbial diversity within prawns across storage times. Treating M. rosenbergii with chitosan inhibited increases in TVB-N, TVC, and K values of prawns, thereby extending prawn meat shelf life by two to three days. During storage, Lactococcus and Candidatus Hepatoplasma became the dominant spoilage bacteria of M. rosenbergii bacterial communities. The abundance of Lactococcus in the experimental M. rosenbergii samples was as high as 69.84% during the late storage stage, while the abundance of Candidatus Hepatoplasma in the control group was as high as 46.88% in the middle storage stage. Chitosan effectively controlled changes in the quality of M. rosenbergii meat during cold storage, altered their bacterial community structures, inhibited spoilage, and exhibited beneficial preservation effects.

Effective control of microbial spoilage in soybeans by water-soluble ZnO nanoparticles

The microbial spoilage of soybeans during soaking process severely deteriorates the quality of soybean products and threatens human health. Herein, water-soluble aminated zinc oxide nanoparticles (ZnO NPs) were developed to effectively control the microbial spoilage in soybeans during soaking. ZnO NPs achieved significant inactivation of three dominant spoilage bacteria (bacillus cereus, bacillus megaterium and enterococcus faecium) isolated from the deteriorated soybeans, which could adhere to the bacterial surface and damage the cell wall/membrane, but also generate large amounts of reactive oxygen species (ROS). Compared to two commercial ZnO, water-soluble ZnO exhibited superior antibacterial properties due to producing more ROS and bacteria-adhered ability. After ZnO NPs treatment, the content of the residual Zn (51.1 mg/kg) in soybeans was the safety standards of Zn element in soybeans products for human). Therefore, the water-soluble ZnO NPs showed great potentials as efficient and safe antimicrobial agents for soybeans preservation during soaking process.

The chemical composition analysis of dwarf saltwort ( Salicornia bigelovii Torr.) and its preservative effects on snakehead fish fillets

In this study, the nutritional component and chemical constituents of Salicornia bigelovii Torr. were investigated, as well as their preservative effects on aquatic products. LC–MS of S. bigelovii extracts detected 34 compounds, eight flavonoids were identified based on standard substance. Camellianin A and noreugenin were identified for the first time in S. bigelovii. Furthermore, the S. bigelovii could reduce the fish fillet loss rate and inhibit the growth of microorganisms in aquatic products that impact cooking loss rate, pH, total volatile basic nitrogen, total viable count, and it also could reduce the damage of myofibrillar proteins texture changes. Finally, the S. bigelovii had a strong inhibitory effect on the dominant spoilage bacteria Pseudomonas in snakehead fish was demonstrated, and significantly prolong the preservation time of fish fillet till the 12 days. Overall, this study provides a basis for the selection of suitable methods for the preservation and processing of aquatic products. Novelty impact statement The Salicornia bigelovii was found a strong inhibitory effect on the bacteria Pseudomonas in snakehead fish, and it can significantly prolong the preservation time of fish fillet, which were expected to be used as the selection of suitable methods for the preservation and processing of aquatic products.

Chitosan-grafted-phenolic acid copolymers against Shewanella putrefaciens by disrupting the permeability of cell membrane.

Chitosan (CS) is a kind of high molecular polymer with antibacterial properties. A copolymer with high bacteriostatic activity can be formed by grafting phenolic acid compounds into the chitosan molecular chain, which can inhibit the growth of dominant spoilage bacteria in aquatic products. The study aimed to investigate the antibacterial effect and mechanism of chitosan-grafted-phenolic acid copolymers on Shewanella putrefaciens (S. putrefaciens). CS-grafted-protocatechuic acid (CS-g-PA) and CS-grafted-gallic acid (CS-g-GA) were attained by EDC/NHS coupling reaction. The antibacterial tests indicated that CS-g-PA and CS-g-GA had the same minimum inhibitory concentration (MIC) (1.25mg/mL) and minimum bactericidal concentration (MBC) (5.0mg/mL) against S. putrefaciens. According to the change trend of growth curve, the growth of S. putrefaciens was significantly restrained under 2MIC graft copolymers (P < 0.05). Moreover, the increment of alkaline phosphatase (AKPase) activity and electrical conductivity demonstrated that the cell wall and membrane permeability of S. putrefaciens were damaged respectively. In addition, the increase of lactate dehydrogenase (LDHase) activity, protein and nucleic acid absorbance and the decrease of adenosine triphosphatase (ATPase) activity suggested that the cell membrane was incomplete and poor fluidity. The irregular shape of bacteria and the outflow of intercellular contents were also observed from scanning electron microscope (SEM). The above results manifested a great potential of CS-g-PA and CS-g-GA for use as food preservatives to aquatic products.

Changes in microbial composition and quality characteristics of yellowfin tuna under different storage temperature

Yellowfin tuna is one of the commercially important fish varieties, and inappropriate storing may deteriorate its safety and quality. This study aimed to investigate the microbial composition and quality characteristics of yellowfin tuna stored at different temperatures for varying amounts of time. With an increase in the storage temperature and storage time, the biogenic amines, the total volatile basic nitrogen TVB-N, and the total viable cell count steadily increased, which influenced the quality of tuna. The most significant histamine concerning food safety reached levels of 21.25, 235.05, 1166.18, and 3799.29 mg/kg, respectively. The values of total viable cell counts were increased to 7.04, 7.97, 8.24, and 8.91 log CFU/g after storage at 0, 4, 10, and 20 °C for 12 days, 7 days, 7 days, 3 days, respectively. Additionally, changes in microbial composition were evaluated by high-throughput sequencing, and the results showed that Pseudomonas was the dominant spoilage bacteria in yellowfin tuna. The bacterial dynamics and their correlation with biogenic amines and TVB-N in yellowfin tuna were analyzed. A positive correlation between Pseudomonas, Shewanella, Morganella, Acinetobacter, and biogenic amines was found. Pseudomonas showed significant correlation with histamine, cadaverine, and putrescine. This study provides insights into yellowfin tuna quality and microbial composition, which provide theoretical guidance for maintaining seafood safety and quality during distribution and storage.

Antibacterial activity and action mechanism of a novel chitosan oligosaccharide derivative against dominant spoilage bacteria isolated from shrimp Penaeus vannamei

With the aim of exploring the potential application of a novel chitosan oligosaccharide derivative (COS-All-Tio) in shrimp preservation, six dominant spoilage bacteria in the spoiled shrimp (Penaeus vannamei) were isolated and identified as Shewanella putrefaciens (RMS1), S. putrefaciens (S2), Pseudomonas weihenstephanensis (P1), P. gessardii (P2), Aeromonas bestiarum (A1) and Aeromonas molluscorum (A2). The antibacterial effect of COS-All-Tio against the six bacterial isolates were studied. Bacterial inhibition zone determination, and minimum inhibitory concentration and minimum bactericidal concentration assays indicated that the antibacterial activity of COS-All-Tio was greatly improved when compared to that of chitosan oligosaccharide (COS). The antibacterial mechanism investigation against S. putrefaciens (RMS1) revealed that COS-All-Tio could inhibit bacterial growth by influencing of membrane integrity. Such disturbance of membrane structure resulted in the leakage of intracellular substance of the bacteria. A strong synergistic antibacterial effect against S. putrefaciens (RMS1) was observed when COS-All-Tio was used in combination with food preservatives (e.g. ε-polylysine hydrochloride). Therefore, COS-All-Tio might have potential in shrimp preservation.

Microbial, chemical qualities and shelf-life of blue swimming crab (Portunus armatus) lump meat as influenced by in-package high voltage cold plasma treatment

The impact of high voltage cold plasma (HVCP) produced by the mixture of gases (oxygen and argon 10:90 v/v) on microbiological and chemical qualities as well as shelf-life of blue swimming crab lump meat (CLM) was investigated. CLM was subjected to HVCP for different treatment times (HV-TT; 0, 5, 10, and 15 min). No bacteria were detected for CLM treated with HVCP for 10 and 15 min (CLM-CP-10 and CLM-CP-15, respectively). However, lipid and protein oxidation in CLM were augmented as HV-TT increased (p < 0.05). Regardless of HV-TT, HVCP had no impact on the color and pH of CLM. Polyunsaturated fatty acid contents in CLM treated with HVCP were decreased, particularly when HV-TT of 15 min was used. CLM had shelf-life of 6 days. Pseudomonas lundensis, Lysinibacillus macroides, Shewanella baltica, Pseudoalteromonas haloplanktis, Paenisporosarcina quisquiliarum, Pseudoalteromonas aliena, and Brochothrix thermosphacta were identified using next generation sequencing as dominant spoilage bacteria in CLM stored at 4 °C for 3 days. At the same refrigeration condition, additional 9 days of shelf-life extension were attained for CLM-CP-10 and CLM-CP-15 compared with the control. Therefore, HVCP with HV-TT of 10 min showed promising potential for extending the shelf-life of CLM for longer than 12 days at 4 °C.

Effects of Different Preservation Treatments on Quality of Wet Rice Noodles and Microbial Diversity of Spoiled Samples

This study aimed to evaluate the quality changes and the growth of microorganisms of wet rice noodles with different preservation treatments during storage at 25 ℃, and analyzed the microbial diversity of spoiled samples based on Illumina Miseq high-throughput sequencing. The results indicated that the shelf life of control sample (CK) was only one day. The rice noodles became sticky and edible quality decreased significantly. Compared to the control, the shelf life of rice noodles treated by acid leaching (CA), acid leaching & e-polylysine hydrochloride (PL), acid leaching & water bath (SY) could be extended to 2, 4 d and 13 d, respectively, and the main spoilage feature was mildew, differ from the control sample, which became sticky and smelly. The results of 16S rDNA indicate that the dominant spoilage bacteria in CK group were Pantoea, Sphingomonas and Bacillus. Different preservative treatments can significantly reduced the diversity of bacterial community. Among which, CA reduced the relative abundance of Sphingomonas and Bacillus, significantly. PL had good inhibitory effect on all three dominant bacterial genuses. ITS rDNA results showed that Rhizopus, belongs to Mucoromycota, was the dominant spoilage fungi in CK, however the relative abundance decreased to less than 0.1% after preservation treatments. While Ascomycota, with strong resistance to stress, became the dominant phylum after preservation treatments. This study provide a theoretical basis for the exploration of preservation technology of wet rice noodles.

Effects of Different Storage Temperatures on the Physicochemical Properties and Bacterial Community Structure of Fresh Lamb Meat.

This study was aimed to compare the physicochemical properties and bacterial community structure of tray-packaged fresh lamb meat under different storage temperatures, such as 4°C (chilling), −1.5°C (supercooling), −4°C (superchilling) and −9°C (sub-freezing). The total viable counts (TVC), total volatile base nitrogen (TVB-N), bacterial diversity and metabolic pathways were investigated. The results indicated that the shelf life of superchilling and sub-freezing storage was over 70 d, which was significantly longer than that of chilling and supercooling storage. TVC and TVB-N values showed an increasing trend and were correlated well (R2>0.92). And the TVB-N values of lamb meat were exceeded the tolerable limit (15 mg/100 g) only found under chilling and supercooling storage during storage period. At the genus level, Pseudomonas was the core spoilage bacteria then followed Brochothrix for chilling and supercooling storage. Pseudomonas, Ralstonia, Psychrobacter and Acinetobacter were the dominant spoilage bacteria for superchilling and sub-freezing storage. Furthermore, the bacterial community diversity of lamb meat stored at chilling and supercooling storage decreased with the storage time prolonged, which was opposite to the outcome of meat stored under superchilling and sub-freezing storage. For chilling and supercooling storage, the abundance of main metabolisms (carbohydrate metabolism and amino acid metabolism, etc.) of bacteria increased with the storage time prolonged, which was opposite to superchilling storage. This may be related to the bacteria community diversity and the formation of dominant spoilage bacteria. In conclusion, this work provides data for the preservation of fresh lamb meat which will benefit the meat industry.

Effects of oregano essential oil and nisin on the shelf life of modified atmosphere packed grass carp (Ctenopharyngodon idellus)

Effects of oregano essential oil (EO) and nisin on the shelf life and microbial community of grass carp fillets packed under modified atmosphere were investigated. The shelf life of fish samples was evaluated based on sensory attributes and spoilage indicators, including color, odor, texture, overall acceptability, total volatile basic nitrogen, and biogenic amines. The addition of oregano EO, nisin, and oregano EO combined with nisin significantly extended the shelf life of fish fillets from 16 d to 20, 20, and 28 d, respectively. In addition, changes in microbial composition of fish fillets were measured by using Illumina-MiSeq high-throughput sequencing and classical microbiological analysis. Adding oregano EO and nisin significantly inhibited the microbial growth of fish fillets, especially lactic acid bacteria which were the dominant spoilage bacteria in fish fillets. While the use of oregano EO and/or nisin did not change the dominant bacteria of fish samples, they significantly lowered total viable counts. Treating fish fillets with nisin lowered the tyramine level and increased the pH value, due to the inhibitory effect on Gram-positive bacteria. The results suggest that oregano EO combined with nisin have great potential to be used as natural antimicrobials to extend the shelf life of grass carp.

Effect of microorganisms on the fingerprint of the volatile compounds in pine nut (Pinus koraiensis) peptide powder during storage.

Pine nut (Pinus koraiensis) peptide (PNP) powder possesses promising bioactivities. However, the powder may have the quality problem of becoming sticky and smelly. Therefore, the volatile compounds' fingerprint of PNP powder was established by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The essential spoilage microorganisms were confirmed by 16S rDNA amplicon sequencing. The antioxidant activity, which presents PNP powder's quality, decreased during storage with the highest value of (1.88±0.18) × 1014 at day 30. Fifty-nine significantly changed signals were detected; eight compounds were considered as volatile marker compounds. Besides, Firmicutes and Cyanobacteria were the essential spoilage microorganisms in PNP powder at the phylum level. Significantly, unidentified_Chloroplast, which belongs to Cyanobacteria, had a positive correlation with volatile marker compounds. The results proved that microorganisms indeed affect volatile compounds of PNP powder and induced off-flavor, including hexanal, which can be used as the detection indicator for the quality control of PNP powder. PRACTICAL APPLICATIONS: In the present study, we controlled the influence of moisture migration on PNP powder and investigated microorganisms' effects on volatile compounds of PNP powder. HS-GC-IMS could be used to establish fingerprints of volatile compounds in PNP powder. 16S rDNA amplicon sequencing method could be used to screen the dominant spoilage bacteria in PNP powder and established essential spoilage microorganisms of PNP powder. This work provides a reference for category identification of PNP powder, which was infected by spoilage bacteria or not, and stored at day 0 or 30days. Hexanal can be considered as the volatile marker compound generated from microorganisms. It helps to realize the controllability of PNP powder storage and prolongs the shelf life of PNP powder.

Characterization of chilled chicken spoilage using an integrated microbiome and metabolomics analysis

Spoilage of chilled chicken can occur as a result of microbial development and consumption of meat nutrients by spoilage bacteria, ultimately resulting in the release of undesired metabolites. Characterizing the profiles of the microbiota and metabolites and clarifying their relationships will contribute to an improved understanding of the mechanism underlying chilled chicken spoilage. In the present study, 16S rRNA gene sequencing and ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS)-based untargeted metabolomics analyses were applied to determine the microbial and metabolic profiles in chicken during chilled storage. The microbial and metabolic datasets were subjected to combined analysis using weighted gene co-expression network analysis (WGCNA) and Spearman’s correlation analysis. Brochothrix, Carnobacterium, Photobacterium, Pseudomonas, Acinetobacter, Serratia, Kurthia, Shewanella, and Obesumbacterium genera were identified as the dominant spoilage bacteria in chilled chicken. Ten metabolic pathways, including histidine metabolism and purine metabolism, were identified as potential mechanisms underlying chilled chicken spoilage. Correlation analysis demonstrated that spoilage bacterial genera were highly correlated with spoilage-related metabolites. Taken together, the present study proposed an integrated microbiome and metabolomics approach to investigate the mechanism of chilled chicken spoilage caused by microbial activity. The results obtained by this approach provide a comprehensive insight into changes in the microbial and metabolic profiles of chilled chicken during spoilage.

Quick assessment of chicken spoilage based on hyperspectral NIR spectra combined with partial least squares regression

Pseudomonas spp. and Enterobacteriaceae are dominant spoilage bacteria in chicken during cold storage (0°C-4°C). In this study, high resolution spectra in the range of 900-1700 nm were acquired and preprocessed using Savitzky-Golay convolution smoothing (SGCS), standard normal variate (SNV) and multiplicative scatter correction (MSC), respectively, and then mined using partial least squares (PLS) algorithm to relate to the total counts of Pseudomonas spp. and Enterobacteriaceae (PEC) of fresh chicken breasts to predict PEC rapidly. The results showed that with full 900-1700 nm range wavelength, MSC-PLS model built with MSC spectra performed better than PLS models with other spectra (RAW-PLS, SGCS-PLS, SNV-PLS), with correlation coefficient (RP) of 0.954, root mean square error of prediction (RMSEP) of 0.396 log10 CFU/g and residual predictive deviation (RPD) of 3.33 in prediction set. Based on the 12 optimal wavelengths (902.2 nm, 905.5 nm, 923.6 nm, 938.4 nm, 946.7 nm, 1025.7 nm, 1124.4 nm, 1211.6 nm, 1269.2 nm, 1653.7 nm, 1691.8 nm and 1693.4 nm) selected from MSC spectra by successive projections algorithm (SPA), SPA-MSC-PLS model had RP of 0.954, RMSEP of 0.397 log10 CFU/g and RPD of 3.32, similar to MSC-PLS model. The overall study indicated that NIR spectra combined with PLS algorithm could be used to detect the PEC of chicken flesh in a rapid and non-destructive way. Keywords: hyperspectral NIR spectra, chicken, dominant spoilage, partial least squares regression, quick assessment DOI: 10.25165/j.ijabe.20211401.5726 Citation: Jiang S Q, He H J, Ma H J, Chen F S, Xu B C, Liu H, et al. Quick assessment of chicken spoilage based on hyperspectral NIR spectra combined with partial least squares regression. Int J Agric & Biol Eng, 2021; 14(1): 243–250.

Antimicrobial and Preservative Effects of the Combinations of Nisin, Tea Polyphenols, Rosemary Extract, and Chitosan on Pasteurized Chicken Sausage

This study was conducted to evaluate the antimicrobial and preservative effects of the combinations of nisin (NS), tea polyphenols (TP), rosemary extract (RE), and chitosan (CS) on pasteurized chicken sausage. An orthogonal test revealed that the most effective preservative was a mixture of 0.05% NS plus 0.05% TP plus 0.03% RE plus 0.55% CS (weight by sausage weight). This mixture had antimicrobial and antioxidant effects in pasteurized chicken sausage and extended the shelf life to >30 days at 4°C. The inhibitory effects of NS, TP, RE, and CS were also evaluated against Pseudomonas aeruginosa, lactic acid bacteria (LAB), and Staphylococcus aureus, the dominant spoilage and pathogenic bacteria in pasteurized chicken sausage. NS had the greatest inhibitory effect on LAB and S. aureus, with inhibitory zone diameters of 19.7 and 17.8 mm, respectively. TP had the largest inhibitory effect on P. aeruginosa, with a clear zone diameter of 18.2 mm. These results indicate that the combination of NS, TP, RE, and CS could be used as a natural preservative to efficiently inhibit the growth of microorganisms in pasteurized chicken sausage and improve its safety and shelf life.

An Active Gelatin Coating Containing Eugenol and Vacuum Delays the Decay of Chinese Seabass (Lateolabrax maculatus) Fillets during Cold Storage: A Microbiome Perspective

The purpose of this study was to evaluate the effect of an active gelatin coating containing eugenol and vacuum on the microbial diversity of Chinese seabass (Lateolabrax maculatus) during cold (−0.9 °C) storage. The bacterial sequences in Chinese seabass were observed using a high-throughput sequencing technique targeting the V3–V4 region of the 16S Ribosomal DNA (rDNA) on 0, 12th, and 24th day, which showed a more comprehensive estimate of the microbial diversity in seabass samples compared with microbial enumeration. The results revealed that the species diversity of fresh seabass was rich, mainly including Carnobacterium, Glutamicibacter, and Pseudomonas, with abundance ratios of 0.286, 0.160, and 0.130, respectively. Pseudomonas and Shewanella were the primary contaminants in the spoiled control samples, where the abundance ratios increased from 0.220 and 0.174 on the 12th day to 0.802 and 0.163 on the 24th day, respectively. Vacuum treatment could inhibit the growth of Pseudomonas and Shewanella such that when stored on the 12th day, Brochothrix became the superior genus. However, Pseudomonas and Shewanella dominated the storage until the 24th day, where their abundance ratios were 0.343 and 0.279, respectively. The inhibition of Pseudomonas and Carnobacterium was gradually enhanced with increasing concentrations of eugenol. Furthermore, an active gelatin coating containing eugenol and vacuum treatment was more effective at inhibiting the increase of the total volatile basic nitrogen. This study confirmed that an active gelatin coating containing eugenol and vacuum could reduce the species of bacteria, inhibit the growth and reproduction of the main dominant spoilage bacteria, and delay the spoilage of seabass.