Microorganisms

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12 pages, 286 KiB

Open AccessArticle

Evaluation of Thymol-β-d-Glucopyranoside as a Potential Prebiotic Intervention to Reduce Carriage of Zoonotic Pathogens in Weaned and Feeder Pigs

by Gizem Levent, Robin C. Anderson, Branko Petrujkić, Toni L. Poole, Haiqi He, Kenneth J. Genovese, Michael E. Hume, Ross C. Beier, Roger B. Harvey and David J. Nisbet

Microorganisms 2021, 9(4), 860; https://doi.org/10.3390/microorganisms9040860 - 16 Apr 2021

Cited by 5 | Viewed by 2546

Abstract

The gut of food-producing animals is a reservoir for foodborne pathogens. Thymol is bactericidal against foodborne pathogens but rapid absorption of thymol from the proximal gut precludes the delivery of effective concentrations to the lower gut where pathogens mainly colonize. Thymol-β-d-glucopyranoside [...] Read more.

The gut of food-producing animals is a reservoir for foodborne pathogens. Thymol is bactericidal against foodborne pathogens but rapid absorption of thymol from the proximal gut precludes the delivery of effective concentrations to the lower gut where pathogens mainly colonize. Thymol-β-d-glucopyranoside is reported to be more resistant to absorption than thymol in everted jejunal segments and could potentially function as a prebiotic by resisting degradation and absorption in the proximal gut but being hydrolysable by microbial β-glycosidase in the distal gut. Previous in vitro studies showed bactericidal effects of thymol-β-d-glucopyranoside against Campylobacter, Escherichia coli, and Salmonella enterica serovar Typhimurium in the presence but not absence of intestinal microbes expressing β-glycosidase activity, indicating that hydrolysis was required to obtain antimicrobial activity. Presently, the oral administration of thymol-β-d-glucopyranoside was studied to examine the effects on intestinal carriage of Campylobacter, E. coli, and S. Typhimurium in swine. The effects of thymol-β-d-glucopyranoside or thymol on antimicrobial sensitivity of representative E. coli isolates and characterized Salmonella strains were also explored. Results from two in vivo studies revealed little antimicrobial effects of thymol-β-d-glucopyranoside on Campylobacter, E. coli, or S. Typhimurium in swine gut. These findings add credence to current thinking that hydrolysis and absorption of thymol-β-d-glucopyranoside and thymol may be sufficiently rapid within the proximal gut to preclude delivery to the distal gut. Antibiotic susceptibilities of selected bacterial isolates and strains were mainly unaffected by thymol. Further research is warranted to overcome obstacles, preventing the delivery of efficacious amounts of thymol-β-d-glucopyranoside to the lower gut. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

15 pages, 339 KiB

Open AccessArticle

Complete Whole Genome Sequences of Escherichia coli Surrogate Strains and Comparison of Sequence Methods with Application to the Food Industry

by Dustin A. Therrien, Kranti Konganti, Jason J. Gill, Brian W. Davis, Andrew E. Hillhouse, Jordyn Michalik, H. Russell Cross, Gary C. Smith, Thomas M. Taylor and Penny K. Riggs

Microorganisms 2021, 9(3), 608; https://doi.org/10.3390/microorganisms9030608 - 16 Mar 2021

Cited by 3 | Viewed by 4131

Abstract

In 2013, the U.S. Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) began transitioning to whole genome sequencing (WGS) for foodborne disease outbreak- and recall-associated isolate identification of select bacterial species. While WGS offers greater precision, certain hurdles must be overcome before [...] Read more.

In 2013, the U.S. Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) began transitioning to whole genome sequencing (WGS) for foodborne disease outbreak- and recall-associated isolate identification of select bacterial species. While WGS offers greater precision, certain hurdles must be overcome before widespread application within the food industry is plausible. Challenges include diversity of sequencing platform outputs and lack of standardized bioinformatics workflows for data analyses. We sequenced DNA from USDA-FSIS approved, non-pathogenic E. coli surrogates and a derivative group of rifampicin-resistant mutants (rif^R) via both Oxford Nanopore MinION and Illumina MiSeq platforms to generate and annotate complete genomes. Genome sequences from each clone were assembled separately so long-read, short-read, and combined sequence assemblies could be directly compared. The combined sequence data approach provides more accurate completed genomes. The genomes from these isolates were verified to lack functional key E. coli elements commonly associated with pathogenesis. Genetic alterations known to confer rif^R were also identified. As the food industry adopts WGS within its food safety programs, these data provide completed genomes for commonly used surrogate strains, with a direct comparison of sequence platforms and assembly strategies relevant to research/testing workflows applicable for both processors and regulators. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

16 pages, 2877 KiB

Open AccessArticle

Dual Inhibition of Salmonella enterica and Clostridium perfringens by New Probiotic Candidates Isolated from Chicken Intestinal Mucosa

by Ayesha Lone, Walid Mottawea, Yasmina Ait Chait and Riadh Hammami

Microorganisms 2021, 9(1), 166; https://doi.org/10.3390/microorganisms9010166 - 13 Jan 2021

Cited by 13 | Viewed by 4250

Abstract

The poultry industry is the fastest-growing agricultural sector globally. With poultry meat being economical and in high demand, the end product’s safety is of importance. Globally, governments are coming together to ban the use of antibiotics as prophylaxis and for growth promotion in [...] Read more.

The poultry industry is the fastest-growing agricultural sector globally. With poultry meat being economical and in high demand, the end product’s safety is of importance. Globally, governments are coming together to ban the use of antibiotics as prophylaxis and for growth promotion in poultry. Salmonella and Clostridium perfringens are two leading pathogens that cause foodborne illnesses and are linked explicitly to poultry products. Furthermore, numerous outbreaks occur every year. A substitute for antibiotics is required by the industry to maintain the same productivity level and, hence, profits. We aimed to isolate and identify potential probiotic strains from the ceca mucosa of the chicken intestinal tract with bacteriocinogenic properties. We were able to isolate multiple and diverse strains, including a new uncultured bacterium, with inhibitory activity against Salmonella Typhimurium ATCC 14028, Salmonella Abony NCTC 6017, Salmonella Choleraesuis ATCC 10708, Clostridium perfringens ATCC 13124, and Escherichia coli ATCC 25922. The five most potent strains were further characterized for their probiotic potential (i.e., sensitivity to antibiotics and tolerance to gastrointestinal physicochemical conditions). Our analyzed lactobacilli strains exhibited some interesting probiotic features while being inhibitory against targeted pathogens. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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15 pages, 1664 KiB

Open AccessArticle

A Role for the Microbiota in the Immune Phenotype Alteration Associated with the Induction of Disease Tolerance and Persistent Asymptomatic Infection of Salmonella in the Chicken

by Annah Lee, Cristiano Bortoluzzi, Rachel Pilla and Michael H. Kogut

Microorganisms 2020, 8(12), 1879; https://doi.org/10.3390/microorganisms8121879 - 27 Nov 2020

Cited by 5 | Viewed by 2781

Abstract

Previous studies have shown a tissue immune phenotype-altering event occurring on days 2 and 4 in the ceca post-Salmonella challenge. To evaluate the involvement of the cecal microbiota in the phenotype reprogramming, we hypothesized that the addition of subtherapeutic bacitracin (BMD) will [...] Read more.

Previous studies have shown a tissue immune phenotype-altering event occurring on days 2 and 4 in the ceca post-Salmonella challenge. To evaluate the involvement of the cecal microbiota in the phenotype reprogramming, we hypothesized that the addition of subtherapeutic bacitracin (BMD) will affect the cecal microbiota. Therefore, the objective of this study was to determine if the antibiotic-mediated changes in the microbiota composition influenced the immune phenotype induced by Salmonella enteritidis infection of the chicken cecum. A total of 112 fertile eggs were obtained for each experiment, repeated for a total of three separate times. The ceca and cecal contents were collected on days 2 and 4 post-infection for mRNA expression TaqMan assay and 16S rRNA gene microbiota sequencing. The results demonstrate the effects of bacitracin on cecal composition and its interaction with Salmonella enteritidis in young chicks. There is a preliminary indication of phenotype change in the Salmonella-challenged group provided subtherapeutic BMD due to the shifting cecal microbiota and cecal immune response, indicating the addition of bacitracin during infection altered the cecal phenotype. These data demonstrate the potential involvement of the microbiota in reprogramming immune phenotype (disease resistance to disease tolerance) induced by Salmonella in the chicken cecum. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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8 pages, 2281 KiB

Open AccessCommunication

Occurrence of tet(O/M/O) Mosaic Gene in Tetracycline-Resistant Campylobacter

by Lorena Hormeño, Maria J. Campos, Santiago Vadillo and Alberto Quesada

Microorganisms 2020, 8(11), 1710; https://doi.org/10.3390/microorganisms8111710 - 31 Oct 2020

Cited by 21 | Viewed by 2734

Abstract

Campylobacter is one of the most important microorganisms responsible for foodborne diseases in the EU. In this study, we investigated resistance to tetracycline in 139 Campylobacter jejuni and Campylobacter coli samples isolated from human clinical cases. From these, 110 were resistant to tetracycline, [...] Read more.

Campylobacter is one of the most important microorganisms responsible for foodborne diseases in the EU. In this study, we investigated resistance to tetracycline in 139 Campylobacter jejuni and Campylobacter coli samples isolated from human clinical cases. From these, 110 were resistant to tetracycline, with MIC (minimal inhibitory concentration) varying in a range of 1 to >512 μg/mL, and 109 (78.4%) carried tet(O), a gene that confers resistance to tetracycline through the expression of a protein that confers protection to the ribosome. Amongst the tetracycline-resistant isolates, one C. jejuni (HCC30) was the only tet(O)-negative sample, presenting an MIC of 256 μg/mL. Instead, the mosaic gene tet(O/M/O) was found in HCC30 and, as far as we know, this is the first description of this chimeric gene originating from homologous recombination between tet(O) and tet(M). The previously described mosaic gene tet(O/32/O), also found in Campylobacter, presents a chimeric structure very similar to that of tet(O/M/O), affecting domains II and III of encoded proteins distantly related to the elongation factor G (EF-G). The tet(O/M/O) mosaic gene has been found in nucleotide databases in several genomes of Campylobacter isolated from different origins, indicating its frequent acquisition, even though it can be undetected through screening by PCR with specific tet(O) primers. In this work, we address the improvement of classical PCR to efficiently diagnose the most prevalent tetracycline resistance determinants in Campylobacter, including tet(O/M/O), which should be taken into account in the optimization of campylobacteriosis treatments. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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9 pages, 235 KiB

Open AccessCommunication

Whole-Genome Sequence of Aeromonas hydrophila CVM861 Isolated from Diarrhetic Neonatal Swine

by Toni L. Poole, Wayne D. Schlosser, Robin C. Anderson, Keri N. Norman, Ross C. Beier and David J. Nisbet

Microorganisms 2020, 8(11), 1648; https://doi.org/10.3390/microorganisms8111648 - 24 Oct 2020

Cited by 8 | Viewed by 2565

Abstract

Aeromonas hydrophila are ubiquitous in the environment and are highly distributed in aquatic habitats. They have long been known as fish pathogens but are opportunistic human pathogens. Aeromonas spp. have persisted through food-processing safeguards and have been isolated from fresh grocery vegetables, dairy, [...] Read more.

Aeromonas hydrophila are ubiquitous in the environment and are highly distributed in aquatic habitats. They have long been known as fish pathogens but are opportunistic human pathogens. Aeromonas spp. have persisted through food-processing safeguards and have been isolated from fresh grocery vegetables, dairy, beef, pork, poultry products and packaged ready-to-eat meats, thus providing an avenue to foodborne illness. A beta-hemolytic, putative Escherichia coli strain collected from diarrheic neonatal pigs in Oklahoma was subsequently identified as A. hydrophila, and designated CVM861. Here we report the whole-genome sequence of A. hydrophila CVM861, SRA accession number, SRR12574563; BioSample number, SAMN1590692; Genbank accession number SRX9061579. The sequence data for CVM861 revealed four Aeromonas-specific virulence genes: lipase (lip), hemolysin (hlyA), cytonic enterotoxin (ast) and phospholipid-cholesterolacyltransferase (GCAT). There were no alignments to any virulence genes in VirulenceFinder. CVM861 contained an E. coli resistance plasmid identified as IncQ1_1__M28829. There were five aminoglycoside, three beta-lactam, and one each of macrolide, phenicol, sulfonamide, tetracycline and trimethoprim resistance genes, all with over 95% identity to genes in the ResFinder database. Additionally, there were 36 alignments to mobile genetic elements using MobileElementFinder. This shows that an aquatic pathogen, rarely considered in human disease, contributes to the resistome reservoir and may be capable of transferring resistance and virulence genes to other more prevalent foodborne strains such as E. coli or Salmonella in swine or other food production systems. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

13 pages, 906 KiB

Open AccessArticle

Effect of a High Proportion of Rye in Compound Feed for Reduction of Salmonella Typhimurium in Experimentally Infected Young Pigs

by Bussarakam Chuppava, Volker Wilke, Clara Berenike Hartung, Amr Abd El-Wahab, Richard Grone, Andreas von Felde, Josef Kamphues and Christian Visscher

Microorganisms 2020, 8(11), 1629; https://doi.org/10.3390/microorganisms8111629 - 22 Oct 2020

Cited by 13 | Viewed by 3262

Abstract

Public health concerns and the potential for food-borne zoonotic transmission have made Salmonella a subject of surveillance programs in food-producing animals. Forty-two piglets (25 d of age and initially 7.48 kg) were used in a 28 d infection period to evaluate the effects [...] Read more.

Public health concerns and the potential for food-borne zoonotic transmission have made Salmonella a subject of surveillance programs in food-producing animals. Forty-two piglets (25 d of age and initially 7.48 kg) were used in a 28 d infection period to evaluate the effects of a high proportion of rye on reducing Salmonella Typhimurium. Piglets were divided into two diet groups: control diet (wheat 69%) and experimental diet (rye 69%). After a one-week adaptation period, all piglets were orally infected with Salmonella Typhimurium (10⁷ log CFU/mL; 2mL/pig). Salmonella in fecal shedding were evaluated at day 1, 3, 5, 7 and then weekly after infection. At the end of the experimental period (at day 28 after infection), the piglets were euthanized to sample feces, cecal digesta contents and ileocecal lymph nodes to determine the bacterial counts of Salmonella. The results suggest that the bacterial counts in the experimental group fed rye diets showed evidence of reducing Salmonella fecal shedding from day 14 onwards and decreasing the number of Salmonella in cecal digesta. However, the translocation of Salmonella in ileocecal lymph nodes was not affected. Furthermore, feed intake, weight gain and feed conversion did not differ between the groups (p > 0.05). Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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6 pages, 469 KiB

Open AccessCommunication

A Preliminary Study on the Presence of Salmonella in Lymph Nodes of Sows at Processing Plants in the United States

by Roger B. Harvey, Keri N. Norman, Robin C. Anderson and David J. Nisbet

Microorganisms 2020, 8(10), 1602; https://doi.org/10.3390/microorganisms8101602 - 18 Oct 2020

Cited by 5 | Viewed by 2210

Abstract

Salmonella-contaminated lymph nodes (LN), when included into edible meat products, are a potential source of Salmonella foodborne disease. In this survey, ventral superficial cervical and mandibular LN were tested for the presence of Salmonella from two sow processing plants in the midwestern [...] Read more.

Salmonella-contaminated lymph nodes (LN), when included into edible meat products, are a potential source of Salmonella foodborne disease. In this survey, ventral superficial cervical and mandibular LN were tested for the presence of Salmonella from two sow processing plants in the midwestern United States. Results indicate that both LN can be contaminated with Salmonella; mandibular LN have higher prevalence (p < 0.05) of Salmonella than cervical LN (16% vs. 0.91%), and the majority (>90%) of Salmonella isolates are pan-susceptible or resistant to one antimicrobial, while 9.78% of isolates were multi-drug-resistant (MDR-resistant to three or more classes of antimicrobials). Intervention methods to prevent foodborne disease could include elimination of these LN from pork products or inclusion of LN only into products that are destined for cooking. Integrated multi-faceted intervention methods need to be developed to reduce Salmonella in the food chain. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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11 pages, 1361 KiB

Open AccessArticle

Inhibition of Salmonella Binding to Porcine Intestinal Cells by a Wood-Derived Prebiotic

by Aleksandar Božić, Robin C. Anderson, Tawni L. Crippen, Christina L. Swaggerty, Michael E. Hume, Ross C. Beier, Haiqi He, Kenneth J. Genovese, Toni L. Poole, Roger B. Harvey and David J. Nisbet

Microorganisms 2020, 8(7), 1051; https://doi.org/10.3390/microorganisms8071051 - 15 Jul 2020

Cited by 4 | Viewed by 3028

Abstract

Numerous Salmonella enterica serovars can cause disease and contamination of animal-produced foods. Oligosaccharide-rich products capable of blocking pathogen adherence to intestinal mucosa are attractive alternatives to antibiotics as these have potential to prevent enteric infections. Presently, a wood-derived prebiotic composed mainly of glucose-galactose-mannose-xylose [...] Read more.

Numerous Salmonella enterica serovars can cause disease and contamination of animal-produced foods. Oligosaccharide-rich products capable of blocking pathogen adherence to intestinal mucosa are attractive alternatives to antibiotics as these have potential to prevent enteric infections. Presently, a wood-derived prebiotic composed mainly of glucose-galactose-mannose-xylose oligomers was found to inhibit mannose-sensitive binding of select Salmonella Typhimurium and Escherichia coli strains when reacted with Saccharomyces boulardii. Tests for the ability of the prebiotic to prevent binding of a green fluorescent protein (GFP)-labeled S. Typhimurium to intestinal porcine epithelial cells (IPEC-J2) cultured in vitro revealed that prebiotic-exposed GFP-labeled S. Typhimurium bound > 30% fewer individual IPEC-J2 cells than did GFP-labeled S. Typhimurium having no prebiotic exposure. Quantitatively, 90% fewer prebiotic-exposed GFP-labeled S. Typhimurium cells were bound per individual IPEC-J2 cell compared to non-prebiotic exposed GFP-labeled S. Typhimurium. Comparison of invasiveness of S. Typhimurium DT104 against IPEC-J2 cells revealed greater than a 90% decrease in intracellular recovery of prebiotic-exposed S. Typhimurium DT104 compared to non-exposed controls (averaging 4.4 ± 0.2 log₁₀ CFU/well). These results suggest compounds within the wood-derived prebiotic bound to E. coli and S. Typhimurium-produced adhesions and in the case of S. Typhimurium, this adhesion-binding activity inhibited the binding and invasion of IPEC-J2 cells. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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12 pages, 1257 KiB

Open AccessArticle

Antibacterial Activity of Four Plant Extracts Extracted from Traditional Chinese Medicinal Plants against Listeria monocytogenes, Escherichia coli, and Salmonella enterica subsp. enterica serovar Enteritidis

by R.L. McMurray, M.E.E. Ball, M.M. Tunney, N. Corcionivoschi and C. Situ

Microorganisms 2020, 8(6), 962; https://doi.org/10.3390/microorganisms8060962 - 26 Jun 2020

Cited by 15 | Viewed by 6212

Abstract

The worldwide ethnobotanical use of four investigated plants indicates antibacterial properties. The aim of this study was to screen and determine significant antibacterial activity of four plant extracts in vitro and in a poultry digest model. Using broth microdilution, the concentrations at which [...] Read more.

The worldwide ethnobotanical use of four investigated plants indicates antibacterial properties. The aim of this study was to screen and determine significant antibacterial activity of four plant extracts in vitro and in a poultry digest model. Using broth microdilution, the concentrations at which four plant extracts inhibited Listeria monocytogenes, Salmonella enteritidis, and Escherichia coli over 24 h was determined. Agrimonia pilosa Ledeb, Iris domestica (L.) Goldblatt and Mabb, Anemone chinensis Bunge, and Smilax glabra Roxb all exhibited a minimum inhibitory concentration (MIC) of 62.5 mg/L and a minimum bactericidal concentration (MBC) of 500 mg/L against one pathogen. A. pilosa Ledeb was the most effective against L. monocytogenes and E. coli with the exception of S. enteritidis, for which A. chinensis Bunge was the most effective. Time–kills of A. pilosa Ledeb and A. chinensis Bunge against L. monocytogenes, E. coli and S. enteritidis incubated in poultry cecum were used to determine bactericidal activity of these plant extracts. A. chinensis Bunge, significantly reduced S. enteritidis by ≥ 99.99% within 6 h. A. pilosa Ledeb exhibited effective significant bactericidal activity within 4 h against L. monocytogenes and E. coli. This paper highlights the potential of these plant extracts to control pathogens commonly found in the poultry gastrointestinal tract. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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11 pages, 1992 KiB

Open AccessArticle

Thymol and Carvacrol Downregulate the Expression of Salmonella typhimurium Virulence Genes during an In Vitro Infection on Caco-2 Cells

by Giulia Giovagnoni, Barbara Rossi, Benedetta Tugnoli, Federico Ghiselli, Andrea Bonetti, Andrea Piva and Ester Grilli

Microorganisms 2020, 8(6), 862; https://doi.org/10.3390/microorganisms8060862 - 7 Jun 2020

Cited by 18 | Viewed by 4346

Abstract

Salmonella typhimurium is one of the major bacteria responsible for gastroenteritis in humans caused by foodborne pathogens. As pork is one of the main routes of transmission, bioactive compounds used as feed additives may be an important strategy to control Salmonella typhimurium. [...] Read more.

Salmonella typhimurium is one of the major bacteria responsible for gastroenteritis in humans caused by foodborne pathogens. As pork is one of the main routes of transmission, bioactive compounds used as feed additives may be an important strategy to control Salmonella typhimurium. The aim of this study was to assess the antimicrobial activity of several organic acids and nature identical compounds against Salmonella typhimurium ATCC^®® 6994™. Moreover, the effect of sub-lethal concentrations of thymol and carvacrol in counteracting a Salmonella typhimurium in vitro infection on Caco-2 cells was evaluated, focusing on the maintenance of the epithelial barrier and the alteration of Salmonella virulence genes. The results showed a protective effect of the compounds on the integrity of the intestinal monolayer, improving transepithelial electrical resistance and bacterial translocation compared to the non-treated cells. A real-time PCR study highlighted a significant downregulation of the main virulence genes of Salmonella (hilA, prgH, invA, sipA, sipC, sipD, sopB, sopE2). These findings indicate that thymol and carvacrol could be good candidates for the control of Salmonella typhimurium in pigs. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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16 pages, 1349 KiB

Open AccessArticle

Products of Lactobacillus delbrueckii subsp. bulgaricus Strain F17 and Leuconostoc lactis Strain H52 Are Biopreservatives for Improving Postharvest Quality of ‘Red Globe’ Grapes

by Xiang Fang, Qinchun Duan, Zhuo Wang, Fuyun Li, Jianxiong Du, Wencan Ke, Diru Liu, Ross C. Beier, Xusheng Guo and Ying Zhang

Microorganisms 2020, 8(5), 656; https://doi.org/10.3390/microorganisms8050656 - 30 Apr 2020

Cited by 12 | Viewed by 3201

Abstract

‘Red Globe’ table grapes are large, edible, seeded fruit with firm flesh that tastes good, but can have poor postharvest shelf-life. This study was conducted to explore the effects of products of Lactobacillus delbrueckii subsp. bulgaricus strain F17 and Leuconostoc lactis strain H52 [...] Read more.

‘Red Globe’ table grapes are large, edible, seeded fruit with firm flesh that tastes good, but can have poor postharvest shelf-life. This study was conducted to explore the effects of products of Lactobacillus delbrueckii subsp. bulgaricus strain F17 and Leuconostoc lactis strain H52 on ‘Red Globe’ table grapes for the enhancement of shelf-life and improvement of grape quality characteristics during postharvest storage. Strains F17 and H52 were isolated from traditional fermented yak milk obtained in the Qinghai–Tibetan Plateau. Samples from untreated and treated grapes were analyzed for physicochemical, biochemical, and microbiological properties (weight loss, decay rate, pH, total soluble solids content, titratable acidity, total phenols, sensory evaluation, and microbial growth) for 20 days. The results demonstrated that supernatants from both strains significantly reduced weight loss, decay rate, aerobic mesophilic bacteria, and coliform bacteria counts; delayed maturity and senescence of table grapes; and reduced titratable acidity and total phenols. However, the supernatant of strain F17 was more effective and resulted in better sensory evaluations and had a significant inhibitory effect on yeast and molds by day 5. Meanwhile, the supernatant from strain H52 had a significant inhibitory effect on fungi over the whole storage period. In addition, the results of the Pearson correlation analysis suggested that weight loss, decay rate, total soluble solids content, and microorganisms were highly correlated with the sensory evaluation data and quality of postharvest grapes when treated with the products of strain F17. On the basis of these data and sensory organoleptic qualities, the supernatant containing products from strain F17 had the best potential as a biopreservative to improve the postharvest quality of ‘Red Globe’ table grapes. Full article

(This article belongs to the Special Issue Control and Intervention Strategies to Reduce Foodborne Pathogens in Animal Agriculture)

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