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Gonçalves MPMBB, do Prado-Silva L, Sant'Ana AS. Emergent methods for inactivation of Cronobacter sakazakii in foods: A systematic review and meta-analysis. Int J Food Microbiol 2024; 421:110777. [PMID: 38909488 DOI: 10.1016/j.ijfoodmicro.2024.110777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/24/2024] [Accepted: 05/31/2024] [Indexed: 06/25/2024]
Abstract
Cronobacter sakazakii is a potentially pathogenic bacterium that is resistant to osmotic stress and low aw, and capable of persisting in a desiccated state in powdered infant milks. It is widespread in the environment and present in various products. Despite the low incidence of cases, its high mortality rates of 40 to 80 % amongst neonates make it a microorganism of public health interest. This current study performed a comparative assessment between current reduction methods applied for C. sakazakii in various food matrices, indicating tendencies and relevant parameters for process optimization. A systematic review and meta-analysis were conducted, qualitatively identifying the main methods of inactivation and control, and quantitatively evaluating the effect of treatment factors on the reduction response. Hierarchical clustering dendrograms led to conclusions on the efficiency of each treatment. Review of recent research trend identified a focus on the potential use of alternative treatments, with most studies related to non-thermal methods and dairy products. Using random-effects meta-analysis, a summary effect-size of 4-log was estimated; however, thermal methods and treatments on dairy matrices displayed wider dispersions - of τ2 = 8.1, compared with τ2 = 4.5 for vegetal matrices and τ2 = 4.0 for biofilms. Meta-analytical models indicated that factors such as chemical concentration, energy applied, and treatment time had a more significant impact on reduction than the increase in temperature. Non-thermal treatments, synergically associated with heat, and treatments on dairy matrices were found to be the most efficient.
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Affiliation(s)
| | - Leonardo do Prado-Silva
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Brazil
| | - Anderson S Sant'Ana
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Brazil.
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Bakshi S, Paswan VK, Yadav SP, Bhinchhar BK, Kharkwal S, Rose H, Kanetkar P, Kumar V, Al-Zamani ZAS, Bunkar DS. A comprehensive review on infant formula: nutritional and functional constituents, recent trends in processing and its impact on infants' gut microbiota. Front Nutr 2023; 10:1194679. [PMID: 37415910 PMCID: PMC10320619 DOI: 10.3389/fnut.2023.1194679] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/30/2023] [Indexed: 07/08/2023] Open
Abstract
Human milk is considered the most valuable form of nutrition for infants for their growth, development and function. So far, there are still some cases where feeding human milk is not feasible. As a result, the market for infant formula is widely increasing, and formula feeding become an alternative or substitute for breastfeeding. The nutritional value of the formula can be improved by adding functional bioactive compounds like probiotics, prebiotics, human milk oligosaccharides, vitamins, minerals, taurine, inositol, osteopontin, lactoferrin, gangliosides, carnitine etc. For processing of infant formula, diverse thermal and non-thermal technologies have been employed. Infant formula can be either in powdered form, which requires reconstitution with water or in ready-to-feed liquid form, among which powder form is readily available, shelf-stable and vastly marketed. Infants' gut microbiota is a complex ecosystem and the nutrient composition of infant formula is recognized to have a lasting effect on it. Likewise, the gut microbiota establishment closely parallels with host immune development and growth. Therefore, it must be contemplated as an important factor for consideration while developing formulas. In this review, we have focused on the formulation and manufacturing of safe and nutritious infant formula equivalent to human milk or aligning with the infant's needs and its ultimate impact on infants' gut microbiota.
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Affiliation(s)
- Shiva Bakshi
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
| | - Vinod Kumar Paswan
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
| | - Satya Prakash Yadav
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
| | - Basant Kumar Bhinchhar
- Department of Livestock Production Management, Sri Karan Narendra Agriculture University, Jobner, India
| | - Sheela Kharkwal
- Department of Agriculture Economics, Sri Karan Narendra Agriculture University, Jobner, India
| | - Hency Rose
- Division of Dairy Technology, ICAR—National Dairy Research Institute, Karnal, India
| | - Prajasattak Kanetkar
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
| | - Vishal Kumar
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
| | - Zakarya Ali Saleh Al-Zamani
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
- Department of Food Technology and Science, Faculty of Agriculture and Veterinary Medicine, Ibb University, Ibb, Yemen
| | - Durga Shankar Bunkar
- Department of Dairy Science and Food Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India
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Isolation and Identification of Cronobacter spp. from Fish and Shellfish Sold in Retail Markets. Curr Microbiol 2021; 78:1973-1980. [PMID: 33774683 DOI: 10.1007/s00284-021-02447-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/10/2021] [Indexed: 10/21/2022]
Abstract
In this study, we investigated the incidence of Cronobacter spp. in seafood collected from retail fish markets of Mumbai, India. A total of 50 samples comprising fresh finfish (n = 32), shellfish (n = 6), dried fish (n = 9) and water (n = 3) were analyzed for Cronobacter spp. by selective enrichment, isolation and biochemical tests. Of 145 isolates presumptively identified as Cronobacter spp. by biochemical tests, 37 were confirmed as Cronobacter spp. by Polymerase Chain Reaction (PCR) specific to the internal transcribed spacer (ITS) regions. Based on the partial ITS gene sequence analysis, 35 isolates were identified as Cronobacter malonaticus and two as Cronobacter sakazakii. The highest incidence of Cronobacter spp. was in dried fish (55.6%), followed by shellfish (33.3%). The virulence gene ompA was detected in two Cronobacter sakazakii isolates. This is the first report of the incidence of Cronobacter spp. in fresh and dried seafood from India, which highlights the need to focus on this emerging pathogen in tropical seafood.
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Labchip-based diagnosis system for on-site application: Sensitive and easy-to-implement detection of single recoverable Cronobacter in infant formula without post-enrichment treatment. Int J Food Microbiol 2020; 327:108659. [PMID: 32413591 DOI: 10.1016/j.ijfoodmicro.2020.108659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 11/20/2022]
Abstract
Microfluidic labchips have achieved much advancement in the molecular diagnosis of foodborne pathogens. Whereas difficulties in the flow control during the transportation of liquid fluids can occur and should be overcome. Manipulations of reaction temperature and the complex procedures from sample pre-treatment to analysis in a single chip device are major obstacles for the on-site application. Thus, the efficient temperature control of samples without any flow of reaction fluids in microfluidic channels of plastic chip and the simplest protocol omitting post-enrichment processing steps may overcome these limitations represented by the stability and the complexity, respectively. This study aims to develop a novel type of labchip and thermocycler specialized for the gene amplification in microfluidic channels and to evaluate the detectability by sensing the minimum recoverable level of Cronobacter in powdered infant formula (PIF). We developed a thermocycling device accelerating reactions through dual heating-blocks optimized to control temperatures of samples in microfluidic-channels by direct contact with labchip sequentially and repetitively. The structural design of microfluidic channels was to eliminate interference factors associated with the optical detection of fluorescent signals (without distortion due to air bubbles in the reaction chamber). To improve the applicability, a portable device and simplified operation to allow direct loading of samples in the chip without post-enrichment procedures were also adopted. Detection performance was evaluated by a sensitivity/specificity tests using 50 isolates of Cronobacter. Cross-reactivity tests for non-Cronobacter organisms and gDNA [human, raw materials of PIF (cow, soybean)] showed that there was no interference-factor causing false-positive results. In terms of the applied research conducted by using PIF, the enrichment of samples without broth medium (distilled water) displayed outstanding performance and 12 h of incubation facilitated detecting target at concentration as low as 1 CFU/300 g PIF (as initial contamination level) without post-enrichment treatment. Validation of the operation conditions using 30 commercial PIF products was also consistent. The present study presents a novel approach of microfluidic technology with perspective to not only the performance and the practicability [easy-to-implement protocol, portable materials, cost-effectiveness (the use of a miniaturized plastic chip requires a minimum level of materials)] for on-site diagnosis.
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Lin Y, Subbiah J, Chen L, Verma T, Liu Y. Validation of radio frequency assisted traditional thermal processing for pasteurization of powdered infant formula milk. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106897] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Cho TJ, Rhee MS. Underrecognized niche of spore-forming bacilli as a nitrite-producer isolated from the processing lines and end-products of powdered infant formula. Food Microbiol 2018; 80:50-61. [PMID: 30704596 DOI: 10.1016/j.fm.2018.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/20/2018] [Accepted: 12/21/2018] [Indexed: 01/14/2023]
Abstract
Although nitrite in powdered milk formula (PIF) is a recognized health risk for infants, the presence of nitrite in PIF has only been investigated as a chemical contaminant during the inspection of end-products. The risk posed by microbial sources of nitrite during the PIF manufacturing process has not been considered. This is the first study to report the taxonomy and physiological characteristics of nitrite-producing bacteria isolated from PIF processing environments. All isolates identified as nitrite-producers (133 out of 501 strains collected over four years) from work-in-process and end-products of PIF were spore-forming bacilli. Nitrite-producing metabolism under PIF processing conditions was found in not only thermophilic isolates (3 Bacillus, 60 Geobacillus from 63 strains; 100%) but also in mesophilic isolates (65 Bacillus, 1 Anoxybacillus from 70 strains; 65.7%). Geobacillus was the only highly heat-resistant sporeformer and vigorous nitrite-producer exhibiting dramatic increases in nitrite over short periods of incubation (a maximum value within 3 h). High conversions of nitrate to nitrite (up to 88.8%) was also observed, highlighting bacteria as a key source of nitrite in PIF processing lines. Further research into the diversity of metabolic activity observed in this study can facilitate specialized management of nitrite-producers in PIF processing lines.
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Affiliation(s)
- Tae Jin Cho
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, South Korea
| | - Min Suk Rhee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, South Korea.
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Omar AM, Tengku Norsalwani T, Asmah M, Badrulhisham Z, Easa AM, Omar FM, Hossain MS, Zuknik M, Nik Norulaini N. Implementation of the supercritical carbon dioxide technology in oil palm fresh fruits bunch sterilization: A review. J CO2 UTIL 2018. [DOI: 10.1016/j.jcou.2018.03.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Decellularization Strategies for Regenerative Medicine: From Processing Techniques to Applications. BIOMED RESEARCH INTERNATIONAL 2017; 2017:9831534. [PMID: 28540307 PMCID: PMC5429943 DOI: 10.1155/2017/9831534] [Citation(s) in RCA: 409] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/15/2017] [Accepted: 04/12/2017] [Indexed: 12/13/2022]
Abstract
As the gap between donors and patients in need of an organ transplant continues to widen, research in regenerative medicine seeks to provide alternative strategies for treatment. One of the most promising techniques for tissue and organ regeneration is decellularization, in which the extracellular matrix (ECM) is isolated from its native cells and genetic material in order to produce a natural scaffold. The ECM, which ideally retains its inherent structural, biochemical, and biomechanical cues, can then be recellularized to produce a functional tissue or organ. While decellularization can be accomplished using chemical and enzymatic, physical, or combinative methods, each strategy has both benefits and drawbacks. The focus of this review is to compare the advantages and disadvantages of these methods in terms of their ability to retain desired ECM characteristics for particular tissues and organs. Additionally, a few applications of constructs engineered using decellularized cell sheets, tissues, and whole organs are discussed.
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Zalepugin DY, Tilkunova NA, Chernyshova IV, Vlasov MI. Sterilization in supercritical media. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2017. [DOI: 10.1134/s199079311608008x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Olabi A, Jinjarak S, Jiménez-Flores R, Walker J, Daroub H. Compositional and sensory differences of products of sweet-cream and whey buttermilk produced by microfiltration, diafiltration, and supercritical CO2. J Dairy Sci 2015; 98:3590-8. [DOI: 10.3168/jds.2014-9141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/05/2015] [Indexed: 11/19/2022]
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Kim SA, Rhee MS. Synergistic antimicrobial activity of caprylic acid in combination with citric acid against both Escherichia coli O157:H7 and indigenous microflora in carrot juice. Food Microbiol 2015; 49:166-72. [PMID: 25846927 DOI: 10.1016/j.fm.2015.02.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/06/2015] [Accepted: 02/09/2015] [Indexed: 10/24/2022]
Abstract
The identification of novel, effective, and non-thermal decontamination methods is imperative for the preservation of unpasteurized and fresh vegetable juices. The aim of this study was to examine the bactericidal effects of caprylic acid + citric acid against the virulent pathogen Escherichia coli O157:H7 and the endogenous microflora in unpasteurized fresh carrot juice. Carrot juice was treated with either caprylic acid, citric acid, or a combination of caprylic acid + citric acid at mild heating temperature (45 °C or 50 °C). The color of the treated carrot juice as well as microbial survival was examined over time. Combined treatment was more effective than individual treatment in terms of both color and microbial survival. Caprylic acid + citric acid treatment (each at 5.0 mM) at 50 °C for 5 min resulted in 7.46 and 3.07 log CFU/ml reductions in the E. coli O157:H7 and endogenous microflora populations, respectively. By contrast, there was no apparent reduction in either population following individual treatment. A validation assay using a low-density E. coli O157:H7 inoculum (3.31 log CFU/ml) showed that combined treatment with caprylic acid (5.0 mM) + citric acid (2.5 mM) at 50 °C for >5 min or with caprylic acid + citric acid (both at 5.0 mM) at either 45 °C or 50 °C for >5 min completely destroyed the bacteria. Combined treatment also increased the redness of the juice, which is a perceived indication of quality. Taken together, these results indicate that combined treatment with low concentrations of caprylic acid and citric acid, which are of biotic origin, can eliminate microorganisms from unpasteurized carrot juice.
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Affiliation(s)
- S A Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea
| | - M S Rhee
- Department of Food Bioscience and Technology, College of Life-Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
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Novel approaches to improve the intrinsic microbiological safety of powdered infant milk formula. Nutrients 2015; 7:1217-44. [PMID: 25685987 PMCID: PMC4344585 DOI: 10.3390/nu7021217] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/29/2015] [Indexed: 02/07/2023] Open
Abstract
Human milk is recognised as the best form of nutrition for infants. However; in instances where breast-feeding is not possible, unsuitable or inadequate, infant milk formulae are used as breast milk substitutes. These formulae are designed to provide infants with optimum nutrition for normal growth and development and are available in either powdered or liquid forms. Powdered infant formula is widely used for convenience and economic reasons. However; current manufacturing processes are not capable of producing a sterile powdered infant formula. Due to their immature immune systems and permeable gastro-intestinal tracts, infants can be more susceptible to infection via foodborne pathogenic bacteria than other age-groups. Consumption of powdered infant formula contaminated by pathogenic microbes can be a cause of serious illness. In this review paper, we discuss the current manufacturing practices present in the infant formula industry, the pathogens of greatest concern, Cronobacter and Salmonella and methods of improving the intrinsic safety of powdered infant formula via the addition of antimicrobials such as: bioactive peptides; organic acids; probiotics and prebiotics.
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Nonthermal Inactivation ofCronobacter sakazakiiin Infant Formula Milk: A Review. Crit Rev Food Sci Nutr 2015; 56:1620-9. [DOI: 10.1080/10408398.2013.781991] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Mondal A, Buchanan RL, Lo YM. Computational fluid dynamics approaches in quality and hygienic production of semisolid low-moisture foods: a review of critical factors. J Food Sci 2014; 79:R1861-70. [PMID: 25224872 DOI: 10.1111/1750-3841.12648] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 07/21/2014] [Indexed: 11/26/2022]
Abstract
Low-moisture foods have been responsible for a number of salmonellosis outbreaks worldwide over the last few decades, with cross contamination from contaminated equipment being the most predominant source. To date, actions have been focused on stringent hygienic practices prior to production, namely periodical sanitization of the processing equipment and lines. Not only does optimum sanitization require in-depth knowledge on the type and source of contaminants, but also the heat resistance of microorganisms is unique and often dependent on the heat transfer characteristics of the low-moisture foods. Rheological properties, including viscosity, degree of turbulence, and flow characteristics (for example, Newtonian or non-Newtonian) of both liquid and semisolid foods are critical factors impacting the flow behavior that consequently interferes heat transfer and related control elements. The demand for progressively more accurate prediction of complex fluid phenomena has called for the employment of computational fluid dynamics (CFD) to model mass and heat transfer during processing of various food products, ranging from drying to baking. With the aim of improving the quality and safety of low-moisture foods, this article critically reviewed the published literature concerning microbial survival in semisolid low-moisture foods, including chocolate, honey, and peanut butter. Critical rheological properties and state-of-the-art CFD application relevant to quality production of those products were also addressed. It is anticipated that adequate prediction of specific transport properties during optimum sanitization through CFD could be used to solve current and future food safety challenges.
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Affiliation(s)
- Arpita Mondal
- Dept. of Nutrition and Food Science, Univ. of Maryland, College Park, MD, 20742, U.S.A
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Ha JW, Kang DH. Synergistic bactericidal effect of simultaneous near-infrared radiant heating and UV radiation against Cronobacter sakazakii in powdered infant formula. Appl Environ Microbiol 2014; 80:1858-63. [PMID: 24413596 PMCID: PMC3957628 DOI: 10.1128/aem.03825-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/02/2014] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to investigate the synergistic bactericidal effects of the simultaneous application of near-infrared (NIR) heating and UV irradiation against Cronobacter sakazakii in powdered infant formula and to determine the effect on quality by measuring color changes and performing sensory evaluation. A cocktail of C. sakazakii strains was inoculated into powdered infant formula, followed by NIR, UV, and combined NIR-UV treatments. The sum of NIR and UV inactivation was lower than that obtained by the simultaneous application of both technologies due to their synergism. Simultaneous NIR-UV combined treatment for 7 min achieved a 2.79-log-unit CFU reduction of C. sakazakii. The underlying inactivation mechanisms of the combined NIR-UV treatment were evaluated by the propidium iodide (PI) uptake test, and we confirmed that disruption of the bacterial cell membrane was the main factor contributing to the synergistic lethal effect. The color values and sensory characteristics of simultaneously NIR-UV-treated infant formula powder were not significantly (P > 0.05) different from those of the control. The results of this study suggest that a NIR-UV decontaminating system can be applied as an alternative to other interventions in powdered weaning foods.
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Affiliation(s)
- Jae-Won Ha
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Institute of GreenBio Science and Technology, Seoul National University, Seoul, South Korea
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Choi M, Kim S, Lee N, Rhee M. New decontamination method based on caprylic acid in combination with citric acid or vanillin for eliminating Cronobacter sakazakii and Salmonella enterica serovar Typhimurium in reconstituted infant formula. Int J Food Microbiol 2013; 166:499-507. [DOI: 10.1016/j.ijfoodmicro.2013.08.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/19/2013] [Accepted: 08/20/2013] [Indexed: 10/26/2022]
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Marked synergistic bactericidal effects and mode of action of medium-chain fatty acids in combination with organic acids against Escherichia coli O157:H7. Appl Environ Microbiol 2013; 79:6552-60. [PMID: 23956396 DOI: 10.1128/aem.02164-13] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to examine the synergistic bactericidal effects of medium-chain fatty acids (MCFAs; caprylic, capric, and lauric acid) and organic acids (OAs; acetic, lactic, malic, and citric acid) against Escherichia coli O157:H7 and to identify their underlying mechanism(s) of action. E. coli O157:H7 was treated with MCFAs, OAs, or different combinations of MCFAs and OAs. Membrane damage and cell morphology were examined by flow cytometry and transmission electron microscopy, respectively. Combined treatment resulted in an additional log-unit reduction compared with the sum of the reductions obtained after individual treatment. For example, caprylic acid (1.0 mM, or 0.016%) and citric acid (1.0 mM, or 0.012%) alone showed negligible bactericidal effects (0.30- and 0.06-log-unit reductions, respectively); however, a marked synergistic effect (>7.15-log-unit reduction) was observed when the two were combined. Although flow cytometry and microscopic analyses of bacteria treated with individual MCFAs and OAs showed evidence of membrane disruption, the bacteria were still able to form colonies; thus, the cell damage was recoverable. In contrast, cells exposed to combined treatments showed clear membrane disintegration and/or cell death (irreversible damage). The mechanism underlying the antimicrobial effects of combined treatment with MCFAs or OAs may involve disruption of the bacterial membrane, which then facilitates the entry of other antimicrobial compounds into the cytoplasm. The main advantage of combined treatment with very low concentrations of natural antimicrobial compounds is that it is very cost-effective. Thus, this approach may be an alternative to more conventional antimicrobial treatments, such as those currently used in public health, medical centers, and the food industry.
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A combined intervention using fermented ethanol and supercritical carbon dioxide to control Bacillus cereus and Bacillus subtilis in rice. Food Control 2013. [DOI: 10.1016/j.foodcont.2012.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Yang Y, Meier F, Ann Lo J, Yuan W, Lee Pei Sze V, Chung HJ, Yuk HG. Overview of Recent Events in the Microbiological Safety of Sprouts and New Intervention Technologies. Compr Rev Food Sci Food Saf 2013. [DOI: 10.1111/1541-4337.12010] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | - Fabienne Meier
- Food Science & Technology Programme; Dept. of Chemistry; National Univ. of Singapore; 3 Science Drive 3; Singapore; 117543
| | - Jerilyn Ann Lo
- Food Science & Technology Programme; Dept. of Chemistry; National Univ. of Singapore; 3 Science Drive 3; Singapore; 117543
| | - Wenqian Yuan
- Food Science & Technology Programme; Dept. of Chemistry; National Univ. of Singapore; 3 Science Drive 3; Singapore; 117543
| | - Valarie Lee Pei Sze
- Food Science & Technology Programme; Dept. of Chemistry; National Univ. of Singapore; 3 Science Drive 3; Singapore; 117543
| | - Hyun-Jung Chung
- Dept. of Food and Nutrition; Inha Univ.; Incheon 402-751; Korea
| | - Hyun-Gyun Yuk
- Food Science & Technology Programme; Dept. of Chemistry; National Univ. of Singapore; 3 Science Drive 3; Singapore; 117543
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Kim SA, Yu JH, Rhee MS. A rapid and simple screening method of Cronobacter spp. in cell suspension and tofu. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2013; 93:1520-1524. [PMID: 22936627 DOI: 10.1002/jsfa.5872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 07/12/2012] [Accepted: 07/26/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND Cronobacter spp. causes illnesses such as neonatal meningitis, sepsis and necrotising enterocolitis that can be fatal in infants and neonates. Thus it is of great concern to the food industry, which requires a simple and miniaturised method for the rapid detection of Cronobacter spp. in food. RESULTS A simple and rapid method was developed for the quantitative estimation of Cronobacter spp. Cell suspension cultures and tofu inoculated with Cronobacter spp. as well as a mixed culture (Cronobacter spp. and other micro-organisms) were serially diluted twofold on microtitre plates. Kim and Rhee broth, containing salicin, was added to each well. After 16-18 h of incubation the colour of broth in the wells changed from purple to yellow owing to salicin fermentation by Cronobacter spp. Bacterial counts were predicted by analysing the end points (the last well number in a series of positive wells). The coefficients of determination (r(2)) between the conventional plating method and the current method had high degrees of correlation (0.954-0.963), suggesting that the latter method offers a reasonable quantification of Cronobacter spp. CONCLUSION The simple method developed in this study could be used for the efficient and rapid screening of Cronobacter spp. in the food industry.
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Affiliation(s)
- Sun Ae Kim
- Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, South Korea
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Callanan M, Paes M, Iversen C, Kleijn R, Bravo Almeida C, Peñaloza W, Johnson N, Vuataz G, Michel M. Behavior of Enterobacter pulveris in amorphous and crystalline powder matrices treated with supercritical carbon dioxide. J Dairy Sci 2012; 95:6300-6. [PMID: 22959935 DOI: 10.3168/jds.2012-5541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 07/08/2012] [Indexed: 11/19/2022]
Abstract
The resistance of an Enterobacter pulveris strain to combined heat and supercritical carbon dioxide (scCO(2)) treatments in different powder matrices was examined. The strain proved resistant to scCO(2) treatment up to 50 MPa pressure at temperatures >73 °C for at least 20 min in a commercial infant formula. Water availability was shown to be important for the observed thermotolerance, because introduction of water in the scCO(2) gas flow during treatment resulted in a 1 log(10) cfu/g reduction of the initial inoculum. Interestingly, similar tolerance to heat and scCO(2) treatment was observed in a less complex matrix, a maltodextrin powder. In contrast, the bacterial strain proved sensitive to lower temperatures (55-65 °C) over shorter times (≤10 min) in a dextrose powder composed of crystalline particles. Therefore, the microorganism demonstrates heat sensitivity in the crystalline powder matrix closer to that of nonpowder liquid matrices. These data demonstrate the increased heat tolerance of the bacterium specifically in amorphous powders and indicate that this characteristic is not dependent on fat and other components commonly found in infant formula. The information is important in designing strategies to deal with contamination of powders with Enterobacteriacae, including pathogenic Cronobacter spp.
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Affiliation(s)
- M Callanan
- Nestlé Research Centre, Nestec Ltd., Vers-Chez-Les-Blanc, 1000 Lausanne 26, Switzerland.
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Kim NH, Yun AR, Rhee MS. Prevalence and classification of toxigenic Staphylococcus aureus isolated from refrigerated ready-to-eat foods (sushi, kimbab and California rolls) in Korea. J Appl Microbiol 2011; 111:1456-64. [PMID: 21972801 DOI: 10.1111/j.1365-2672.2011.05168.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To investigate the presence of toxigenic Staphylococcus aureus in ready-to-eat (RTE) Korean foods and determine the distribution of genes related to various types of toxin production. METHODS AND RESULTS A total of 3293 commercial RTE refrigerated foods (sushi, n = 1882; kimbab, n = 975; California rolls, n = 436) were collected from Korean grocery stores, department stores and convenience stores between January 2006 and June 2007. Of these, 197 (5.98%) RTE samples were contaminated with coagulase-positive Staph. aureus, that is, 61 (6.26%) kimbab, 110 (5.84%) sushi and 26 (5.96%) California rolls. Multiplex PCR determined the presence of 12 toxigenic genes: sea, seb, sec, sed, see, seg, seh, sei, sej, tst-1, eta and etb. Approximately half (49.75%) of the Staph. aureus isolates had toxigenic properties, and most of the toxigenic isolates possessed genes coding for the simultaneous production of two or more types of toxin. The most frequent toxigenic types found in Korean RTE foods were as follows: seg = sei > sea > tst-1 > etb > seh > eta > sec > sej. CONCLUSIONS This study provided a comprehensive analysis of toxigenic S. aureus isolates from Korean RTE foods and their toxigenicity types. This emphasizes the potential risk of various types of toxigenic Staph. aureus in refrigerated RTE food products, which should be better managed to establish safer food chains in global food markets. SIGNIFICANCE AND IMPACT OF THE STUDY This result may contribute to an extended database on Staph. aureus food contamination and mitigate the lack of available information on microbiological hazards in Southeast Asian Nations.
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Affiliation(s)
- N H Kim
- Division of Food Bioscience and Technology, Korea University, Seoul, South Korea
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Kim S, Oh S, Lee Y, Imm J, Hwang I, Kang D, Rhee M. Microbial contamination of food products consumed by infants and babies in Korea. Lett Appl Microbiol 2011; 53:532-8. [DOI: 10.1111/j.1472-765x.2011.03142.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kim S, Rhee M. A new cost-effective, selective and differential medium for the isolation of Cronobacter spp. J Microbiol Methods 2011; 85:149-54. [DOI: 10.1016/j.mimet.2011.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 02/08/2011] [Accepted: 02/14/2011] [Indexed: 11/17/2022]
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