Common Spoilage Bacteria Research Articles

LC-MS/MS-based peptidomics and metabolomics reveal different metabolic patterns of common spoilage bacteria in grass carp flesh

Grass carp are highly perishable under the action of spoilage bacteria including Aeromonas rivipollensis, Pseudomonas putida, and Shewanella putrefaciens. However, the metabolic characteristics of the three bacteria in degrading fish proteins and small molecular nutrients are unclear. In this study, we used LC-MS/MS-based peptidomics and metabolomics to detect peptides and small molecular metabolites in grass carp flesh inoculated with the three bacteria. The peptidomic results showed that A. rivipollensis and S. putrefaciens induced an overall increase in the molecular weight of peptides in grass carp flesh. S. putrefaciens tended to hydrolyze peptide bonds composed of at least one hydrophobic amino acid whereas A. rivipollensis and P. putida preferred hydrolyzing Xaa-serine bonds. The metabolomic results showed that amino acid metabolism and nucleotide metabolism are among the most enriched pathways of differential metabolites. P. putida and S. putrefaciens were active in decomposing amino acids and nucleosides, respectively. Besides, lipid metabolism also plays an important role in grass carp spoilage, representing as the degradation from phosphatidylcholine to lysophosphatidylcholine by the three bacteria. To conclude, this study revealed distinct metabolic characteristics of the three bacteria in degrading proteins and small molecular metabolites, and thus contribute to the understanding of fish spoilage mechanisms.

Bioprotective potential of Latilactobacillus sakei and Latilactobacillus curvatus in smoked chicken legs with modified atmosphere packaging

The effects of inoculation with bioprotective bacteria (Latilactobacillus sakei and Latilactobacillus carvatus) on the bacterial succession, physicochemical properties, volatile organic compound (VOCs), and sensory attributes of smoked chicken legs stored in modified atmosphere packaging (MAP, 60% CO2 and 40% N2) at 4 °C for 28 days were investigated. Compared with the control (without inoculation), inoculation with L. sakei and L. curvatus inhibited the growth of common spoilage bacteria (Serratia proteamaculans, Weissella ceti, and Pseudomonas fragi) in smoked chicken legs stored in MAP. They significantly (P < 0.05) decreased the levels of lipid oxidation and spoilage markers such as ethanol, 1-octen-3-ol, carbon disulfide, cyclooctanol, 2,3-butanediol, and 3-methyl-1-butanol, slowed down the deterioration of the surface skin color and odor, and prolonged the shelf-life of the product. Inoculation with L. sakei and L. curvatus extended the shelf life of smoked chicken legs stored in MAP by 7 and 14 days, respectively.

Contribution of mono- and co-culture of Pseudomonas paralactis, Acinetobacter MN21 and Stenotrophomonas maltophilia to the spoilage of chill-stored lamb

Exploring the contribution of common microorganisms to spoilage is of great significance in inhibiting spoilage in lamb. This work investigated the extent of protein degradation and profile changes of free amino acids (FAAs), free fatty acids (FFAs) and volatile organic compounds (VOCs) in lamb caused by single- and co-culture of the common aerobic spoilage bacteria, P. paralactis, Ac. MN21 and S. maltophilia. Meanwhile, some key VOCs produced by the three bacteria during lamb spoilage were also screened by orthogonal partial least square discriminant analysis and difference value in VOCs content between inoculated groups and sterile group. Lamb inoculated with P. paralactis had the higher total viable counts, pH, total volatile base nitrogen and TCA-soluble peptides than those with the other two bacteria. Some FAAs and FFAs could be uniquely degraded by P. paralactis but not Ac. MN21 and S. maltophilia, such as Arg, Glu, C15:0, C18:0 and C18:1n9t. Co-culture of the three bacteria significantly promoted the overall spoilage, including bacterial growth, proteolysis and lipolysis. Key VOCs produced by P. paralactis were 2, 3-octanedione, those by Ac. MN21 were 1-octanol, octanal, hexanoic acid, 1-pentanol and hexanoic acid methyl ester, and that by S. maltophilia were hexanoic acid. The production of extensive key-VOCs was significantly and negatively correlated with C20:0, C23:0 and C18:ln9t degradation. This study can provide a basis for inhibiting common spoilage bacteria and promoting high-quality processing of fresh lamb.

Changes in selenium-enriched chicken sausage containing chitosan nanoemulsion and quality changes in the nanoemulsion during storage

A novel food-processing technology of selenium (Se)-enriched chicken sausage has been developed. The process consists of two different concentrations (250 mg/kg and 500 mg/kg) of chitosan nanoemulsions, which are added to Se-enriched chicken sausage to significantly reduce the pH, total volatile basic nitrogen (TVB-N), and thiobarbituric acid reactive substances (TBARS) (P < 0.05) during storage. This approach is known to reduce the quality deterioration in Se-enriched chicken sausage. In addition, the chitosan content of 250 mg/kg in the nanoemulsion affected the odor and unsaturated fatty acid content of chicken sausages. Partial least squares discriminant analysis (PLS-DA) revealed cyclotrisiloxane as the key to distinguish the treatment group from the control group. In addition, the chitosan nanoemulsion effectively inhibited the growth of common spoilage bacteria of chicken sausages. In all, the chitosan nanoemulsion decreased the spoilage rate in chicken sausage and reduced bacteria spoilage, indicating its potential as a new food additive.

Identification of Spoilage Bacteria in Non-Food Products and Their Inhibition Using Botanical Extracts

Microbial contamination of non-food products is unavoidable since most industrial production cannot guarantee completely sterile end products. Therefore, biocides are added to postpone spoilage. In the last decade, legislation and social acceptance of chemicals have changed tremendously, leading to a growing interest in botanical extracts as alternatives. Here, we identified the bacterial contaminants from 16 expired non-food products, both by a culturing method and a metagenetics approach, revealing Enterobacteriaceae and Pseudomonadaceae as the most common spoilage bacteria. Next, we evaluated 636 botanical extracts for antibacterial activity against a panel of 11 challenge strains, showing broad activity for extracts of a.o. Glycyrrhiza glabra, Ficus hispida, and Toddalia asiatica. Finally, their antibacterial activity was evaluated against Escherichia coli and Staphylococcus aureus in a paint and a detergent product matrix, showing their potential as more sustainable alternatives to synthetic chemical biocides.

Amino acid degradation and related quality changes caused by common spoilage bacteria in chill-stored grass carp (Ctenopharyngodon idella)

To characterize the involvement of microorganisms in amino acid degradation and fish quality deterioration, three major grass carp spoilage bacteria were artificially inoculated in amino acid solutions (in-vitro) and grass carp flesh (in-situ). Results showed that Pseudomonas putida largely degraded free amino acids and produced 3.78 mM/100 g ammonia in grass carp flesh, relying on its high amino acid deamination11Amino acid deamination in this article refers to the collection of all bioreactions catalyzing the removal of the amino groups from amino acids. It can include bioreactions induced by amino acid oxidative deaminase, lyases, and dehydratases. activity. Aeromonas rivipollensis produced 3-Methyl-butanol and 2-Methyl-butanol through leucine and isoleucine degradation. Shewanella putrefaciens had potent ornithine-decarboxylation activity (423.91 × 10−9 µg/CFU) and released 22.98 mg/kg putrescine in situ. S. putrefaciens could produce more putrescine when cooperating with P. putida through the arginine deiminase pathway. To conclude, the biochemical activities identified through in-vitro tests correlated well with quality changes in inoculated grass carp flesh. The outcomes of this study provided fundamental information on the spoilage mechanisms of freshwater fish and important guidance for the development of quality control strategies.

Comparison between cage and free-range egg production on microbial composition, diversity and the presence of Salmonella enterica

The microbial composition of the food production environment plays an important role in food safety and quality. This study employed both 16 S rRNA gene sequencing technology and culture-based techniques to investigate the bacterial microbiota of an egg production facility comprising of both free-range and conventional cage housing systems. The study also aimed to detect the presence of Salmonella enterica and determine whether its presence was positively or negatively associated with other taxa. Our findings revealed that microbiota profiles of free-range and cage houses differ considerably in relation to the relative abundance and diversity with a number of taxa unique to each system and to individual sampling sites within sheds. Core to each housing system were known inhabitants of the poultry gastrointestinal tracts, Romboutsia and Turicibacter, as well as common spoilage bacteria. Generally, free-range samples contained fewer taxa and were dominated by Staphylococcus equorum, differentiating them from the cage samples. Salmonella enterica was significantly associated with the presence of a taxa belonging to the Carnobacteriaceae family. The results of this study demonstrate that the diversity and composition of the microbiota is highly variable across egg layer housing systems, which could have implications for productivity, food safety and spoilage.

Effect of a sea buckthorn pomace extract-esterified potato starch film on the quality and spoilage bacteria of beef jerky sold in supermarket

A new food packaging material was developed for beef jerky. The material consists of an esterified potato starch film with 3 different concentrations (2%, 4%, and 6%, w/w) of sea buckthorn pomace extract. The packaged beef jerky was kept in supermarket. The sea buckthorn pomace extract-esterified potato starch film (SPF) packaging significantly reduces the water loss, L*, a*, thiobarbituric acid reactive substances (TBARS) and the total volatile basic nitrogen (TVB-N) of beef jerky during storage (p < 0.05), demonstrating a protective effect to reduce the deterioration of the quality. However, a high content of sea buckthorn pomace extract in film (6%) also affects the smell of beef jerky. Moreover, SPF effectively inhibits the growth of common spoilage bacteria in beef jerky. These results demonstrated that SPF reduces the deterioration rate of the beef jerky and the decreases the spoilage by bacteria, which both gives SPE a high potential as a new packaging material.

Antibacterial effect of flavonoids in castanea mollissima blume on common spoilage bacteria in low-temperature meat products

The oxford cup method and filter paper method were used to determine the antibacterial effect of flavonoids extracted from castanea mollissima blume, three kinds of common spoilage bacteria in low-temperature meat products were subjects to be tested, named proteus, macrococcus and bacillus. The results showed that flavonoids in castanea mollissima blume had an antibacterial effect on proteus and macrococcus. For flavonoid glycosides, the diameters of inhibition zone were 16.32 mm and 17.76 mm, and the minimum inhibitory concentration were 0.00625 g/mL and 0.0125 g/mL, respectively. The effective inhibitory time was 14 h. For free flavonoids, the maximum diameter of the inhibition zone was 7 mm, the minimum inhibitory concentration was 0.0125 g/mL. They had no antibacterial effect on bacillus. As natural bacteriostatic agents, the flavonoids in castanea mollissima blume are likely to have many important applications in meat products in the future.

Caseinate-Stabilized Emulsions of Black Cumin and Tamanu Oils: Preparation, Characterization and Antibacterial Activity.

Caseinate-stabilized emulsions of black cumin (Nigella sativa) and tamanu (Calophyllum inophyllum) oils were studied in terms of preparation, characterization, and antibacterial properties. The oils were described while using their basic characteristics, including fatty acid composition and scavenging activity. The oil-in-water (o/w) emulsions containing the studied oils were formulated, and the influence of protein stabilizer (sodium caseinate (CAS), 1–12 wt %), oil contents (5–30 wt %), and emulsification methods (high-shear homogenization vs. sonication) on the emulsion properties were investigated. It was observed that, under both preparation methods, emulsions of small, initial droplet sizes were predominantly formed with CAS content that was higher than 7.5 wt %. Sonication was a more efficient emulsification procedure and was afforded emulsions with smaller droplet size throughout the entire used concentration ranges of oils and CAS when compared to high-shear homogenization. At native pH of ~ 6.5, all of the emulsions exhibited negative zeta potential that originated from the presence of caseinate. The antibacterial activities of both oils and their emulsions were investigated with respect to the growth suppression of common spoilage bacteria while using the disk diffusion method. The oils and selected emulsions were proven to act against gram positive strains, mainly against Staphylococcus aureus (S. aureus) and Bacillus cereus (B. cereus); regrettably, the gram negative species were fully resistant against their action.

Spoilage bacteria pseudomonas - production of hydrolytic enzymes and ability to grow at 5°C

Microbial growth and metabolism in food leads to organoleptic spoilage through altering colour, odour and texture of food, and slime or liquid production on the surface. In the dynamics of organoleptic spoilage, initial microbial contamination and storage temperature of food play an important role. Bacteria Pseudomonas are known as the most common spoilage bacteria. Aim of this study was to evaluate the ability of selected Pseudomonas strains to grow at 5?C in different food models, and to evaluate their spoilage potential as the ability to produce different hydrolytic enzymes at 5?C. This was determined through monitoring the number of bacterial cells in food models at 5?C, over 9 days of incubation, and on agars for detection of proteolytic and lipolytic activity. Of the four selected Pseudomonas strains (P. fragi CC151, P. fragi CC275, P. psychrophila CC291, P. lactis CC194), all were capable of producing lipolytic and proteolytic enzymes. When monitoring Pseudomonas growth in different food models (minced meat, pasteurized milk, apples) as compared to broth, the best growth was achieved in minced meat model, and the lowest in apple model. Thereby, the importance of the nutrients availability and the use of hydrolytic enzymes to exploit more complex nutrient molecules, especially proteins, has been confirmed. Selected Pseudomonas strains are able to grow in a variety of food media, and have the ability to produce hydrolytic enzymes, confirming their universality as refrigerated food spoilers, with high potential of persisting in the food storage environment.

Exploring lot-to-lot variation in spoilage bacterial communities on commercial modified atmosphere packaged beef

Understanding the factors influencing meat bacterial communities is important as these communities are largely responsible for meat spoilage. The composition and structure of a bacterial community on a high-O2 modified-atmosphere packaged beef product were examined after packaging, on the use-by date and two days after, to determine whether the communities at each stage were similar to those in samples taken from different production lots. Furthermore, we examined whether the taxa associated with product spoilage were distributed across production lots. Results from 16S rRNA amplicon sequencing showed that while the early samples harbored distinct bacterial communities, after 8–12 days storage at 6 °C the communities were similar to those in samples from different lots, comprising mainly of common meat spoilage bacteria Carnobacterium spp., Brochothrix spp., Leuconostoc spp. and Lactococcus spp. Interestingly, abundant operational taxonomic units associated with product spoilage were shared between the production lots, suggesting that the bacteria enable to spoil the product were constant contaminants in the production chain. A characteristic succession pattern and the distribution of common spoilage bacteria between lots suggest that both the packaging type and the initial community structure influenced the development of the spoilage bacterial community.

Microbiological Quality and Safety of Energy Drink Available in the Local Markets in Saudi Arabia

Energy drinks have become a popular beverage worldwide. The global market for energy drink has gained momentum in the past decade, and demand is increasing every year. The objective of this study was to evaluate the microbiological quality and safety of commercial energy drinks available in the local stores in Saudi Arabia. Total bacterial count, coliform, Escherichia coli, Salmonella, and Staphylococcus aureus were included in this analysis. Out of a total of 20 tested energy drinks, microbial con- tamination was present in only two products. Microbial levels of the total bacterial count for most of the samples were very low (< 1.0 log CFU/ml). The initial biochemical analysis from these two samples indicated the presence of Bacillus which is common spoilage bacteria in soft drinks showed bacterial contamination. In addition, we also tested the impact of energy drinks on beneficial microorganisms ( Bifidobacterium and Lactobacillus spp). We found that in all tested energy drinks bacte- rial population decreased by at least 4.0 log CFU/ml indicating the negative effects of drinks on the survival of beneficial microorganisms. Our findings suggested that safety improvements are needed in these energy drinks. Moreover, consumers also need to be educated regarding the impact of various ingredients, their safety, and recommendation regarding the use of these drinks. This will help to ensure safe products available for today's savvy, health-conscious consumer. Thus, the proposed methodology could be useful for quality and safety control purposes in the energy drinks industry.

Nitrogen gas flushing can be bactericidal: the temperature-dependent destiny of Bacillus weihenstephanensis KBAB4 under a pure N2 atmosphere.

Gram-negative Pseudomonas and Gram-positive Bacillus are the most common spoilage bacteria in raw and pasteurized milk, respectively. In previous studies, nitrogen (N2) gas flushing treatments of raw and pasteurized milk at cold chain-temperatures inhibited bacterial spoilage and highlighted different susceptibilities to the N2 treatment with the exclusion of certain bacterial types. Here, we investigated the effects of pure N2 gas flushing on representative strains of these genera grown in mono- or co-cultures at 15 and 25°C. Bacillus weihenstephanensis, a frequent inhabitant of fluid dairy products, is represented by the genome-sequenced KBAB4 strain. Among Pseudomonas, P. tolaasii LMG 2342T and strain C1, a raw milk psychrotroph, were selected. The N2 gas flushing treatment revealed: (1) temperature-dependent responses; (2) inhibition of the growth of both pseudomonads; (3) emergence of small colony variants (SCVs) for B. weihenstephanensis strain KBAB4 at 15°C induced by the N2 treatment or when grown in co-culture with Pseudomonas strains; (4) N2 gas flushing modulates (suppressed or stimulated) bacterial antagonistic reactions in co-cultures; (5) most importantly, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed that at 25°C the majority of the KBAB4 cells were killed by pure N2 gas flushing. This observation constitutes the first evidence that N2 gas flushing has bactericidal effects.

Kinetics of biofilm formation and desiccation survival of Listeria monocytogenes in single and dual species biofilms with Pseudomonas fluorescens, Serratia proteamaculans or Shewanella baltica on food-grade stainless steel surfaces

This study investigated the dynamics of static biofilm formation (100% RH, 15 °C, 48–72 h) and desiccation survival (43% RH, 15 °C, 21 days) of Listeria monocytogenes, in dual species biofilms with the common spoilage bacteria, Pseudomonas fluorescens, Serratia proteamaculans and Shewanella baltica, on the surface of food grade stainless steel. The Gram-negative bacteria reduced the maximum biofilm population of L. monocytogenes in dual species biofilms and increased its inactivation during desiccation. However, due to the higher desiccation resistance of Listeria relative to P. fluorescens and S. baltica, the pathogen survived in greater final numbers. In contrast, S. proteamaculans outcompeted the pathogen during the biofilm formation and exhibited similar desiccation survival, causing the N21 days of Serratia to be ca 3 Log10(CFU cm−2) greater than that of Listeria in the dual species biofilm. Microscopy revealed biofilm morphologies with variable amounts of exopolymeric substance and the presence of separate microcolonies. Under these simulated food plant conditions, the fate of L. monocytogenes during formation of mixed biofilms and desiccation depended on the implicit characteristics of the co-cultured bacterium.

Determination of Microbial Growth and Survival in Salad Vegetables through in Vitro Challenge Test

Current study attempted to examine the growth and subsequent survival of the common spoilage bacteria in vegetable samples collected from Dhaka, Bangladesh. Carrot, cucumber, tomato and lettuce samples were obtained from local markets and rendered free of contaminants. Each sample was then inoculated separately with an array of 9 test bacteria, resulting in the initial load of 105 cfu/g. The results revealed more than 6-log reduction of Salmonella spp. in carrot and tomato samples, Shigella spp. in carrot, lettuce and cucumber samples, Aeromonas spp. in tomato samples, Pseudomonas spp. in lettuce samples, and Listeria spp. in cucumber samples. No significant reduction in E. coli was observed in the cucumber samples, while in carrots and tomato samples, approximately 2- log reductions was found. Demonstration of the capacity of vegetables to influence microbial growth would further aid in the maintenance of the food quality and stability as well as their shelf life. Conducting such experiments after the quantification of spoiling microorganisms thus imparts a complete bacteriological profile, which is of public health significance.

A comparison of single oxidants versus advanced oxidation processes as chlorine-alternatives for wild blueberry processing ( Vaccinium angustifolium)

Advanced oxidation processes and single chemical oxidants were evaluated for their antimicrobial efficacy against common spoilage bacteria isolated from lowbush blueberries. Predominant bacterial flora were identified using biochemical testing with the assessment of relative abundance using non-selective and differential media. Single chemical oxidants evaluated for postharvest processing of lowbush blueberries included 1% hydrogen peroxide, 100 ppm chlorine, and 1 ppm aqueous ozone while advanced oxidation processes (AOPs) included combinations of 1% hydrogen peroxide/UV, 100 ppm chlorine/UV, and 1 ppm ozone/1% hydrogen peroxide/UV. Enterobacter agglomerans and Pseudomonas fluorescens were found to comprise 90–95% of the bacterial flora on lowbush blueberries. Results of inoculation studies reveal significant log reductions ( p ≤ 0.05) in populations of E. agglomerans and P. fluorescens on all samples receiving treatment with 1% hydrogen peroxide, 1% hydrogen peroxide/UV, 1 ppm ozone, or a combined ozone/hydrogen peroxide/UV treatment as compared to chlorine treatments and unwashed control berries. Although population reductions approached 2.5 log CFU/g, microbial reductions among these treatments were not found to be significantly different ( p ≤ 0.05) from each other despite the synergistic potential that should result from AOPs; furthermore, as a single oxidant, UV inactivation of inoculated bacteria was minimal and did not prove effective as a non-aqueous bactericidal process for fresh pack blueberries. Overall, results indicate that hydrogen peroxide and ozone, as single chemical oxidants, are as effective as AOPs and could be considered as chlorine-alternatives in improving the microbiological quality of lowbush blueberries.