Faster Detection of<i>Staphylococcus aureus</i>in Milk and Milk Powder by Flow Cytometry

Liu, Siyuan; Wang, Bin; Sui, Zhiwei; Wang, Ziquan; Li, Longquan; Zhen, Xiaoxiao; Zhao, Wei; Zhou, Guoping

doi:10.1089/fpd.2020.2894

Cited by 13 publications

(4 citation statements)

References 24 publications

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“…Initially, the milk powder sample (25 g) was added to 225 mL of PBS. As described previously, 24 to isolate bacterial cells, 2.5 mg of proteinase K and 500 μL of Triton X-100 (0.1% w/v) were added to 1.5 mL of the mixture containing infant formula. Notably, the treated samples were incubated at 37 °C for 15 min as the specified temperature and time were conducive to enzyme activity in the purification solution.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Rapid and Accurate Quantification of Viable Lactobacillus Cells in Infant Formula by Flow Cytometry Combined with Propidium Monoazide and Signal-Enhanced Fluorescence In Situ Hybridization

Wang,

Liu,

Wang

et al. 2024

Anal. Chem.

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Lactobacillus is an important member of the probiotic bacterial family for regulating human intestinal microflora and preserving its normalcy, and it has been widely used in infant formula. An appropriate and feasible method to quantify viable Lactobacilli cells is urgently required to evaluate the quality of probiotic-fortified infant formula. This study presents a rapid and accurate method to count viable Lactobacilli cells in infant formula using flow cytometry (FCM). First, Lactobacillus cells were specifically and rapidly stained by oligonucleotide probes based on a signal-enhanced fluorescence in situ hybridization (SEFISH) technique. A DNA-binding fluorescent probe, propidium monoazide (PMA), was then used to accurately recognize viable Lactobacillus cells. The entire process of this newly developed PMA-SEFISH-FCM method was accomplished within 2.5 h, which included pretreatment, dual staining, and FCM analysis; thus, this method showed considerably shorter time-to-results than other rapid methods. This method also demonstrated a good linear correlation (R 2 = 0.9994) with the traditional plate-based method with a bacterial recovery rate of 91.24%. To the best of our knowledge, the present study is the first report of FCM combined with PMA and FISH for the specific detection of viable bacterial cells.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Rapid and Accurate Quantification of Viable Lactobacillus Cells in Infant Formula by Flow Cytometry Combined with Propidium Monoazide and Signal-Enhanced Fluorescence In Situ Hybridization

Wang,

Liu,

Wang

et al. 2024

Anal. Chem.

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“…For example, a staining system combining fluorescently labeled antibodies and propidium iodide (cell-permeable red fluorescent dye) was developed to detect viable S. aureus cells in milk and milk powder using FCM. With a 5 h pre-enrichment period, the method could detect low numbers of S. aureus in 6 h with an LOD of 7.50 cells/mL for milk and 8.30 cells/g for milk powder [42]. Another FCM method provided the detection and differentiation of probiotic strains of B. subtilis and other Bacillus species.…”

Section: Flow Cytometry and Cell Countingmentioning

confidence: 99%

Oxygen Sensor-Based Respirometry and the Landscape of Microbial Testing Methods as Applicable to Food and Beverage Matrices

Papkovsky

Kerry

2023

Sensors

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The current status of microbiological testing methods for the determination of viable bacteria in complex sample matrices, such as food samples, is the focus of this review. Established methods for the enumeration of microorganisms, particularly, the ‘gold standard’ agar plating method for the determination of total aerobic viable counts (TVC), bioluminescent detection of total ATP, selective molecular methods (immunoassays, DNA/RNA amplification, sequencing) and instrumental methods (flow cytometry, Raman spectroscopy, mass spectrometry, calorimetry), are analyzed and compared with emerging oxygen sensor-based respirometry techniques. The basic principles of optical O2 sensing and respirometry and the primary materials, detection modes and assay formats employed are described. The existing platforms for bacterial cell respirometry are then described, and examples of particular assays are provided, including the use of rapid TVC tests of food samples and swabs, the toxicological screening and profiling of cells and antimicrobial sterility testing. Overall, O2 sensor-based respirometry and TVC assays have high application potential in the food industry and related areas. They detect viable bacteria via their growth and respiration; the assay is fast (time to result is 2–8 h and dependent on TVC load), operates with complex samples (crude homogenates of food samples) in a simple mix-and-measure format, has low set-up and instrumentation costs and is inexpensive and portable.

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“…Following enrichment, limit of detection for viable S. aureus ranged from 10 2 cfu/mL (3 h enrichment) to 10 1 cfu/ mL (6 h enrichment) in spiked milk samples (Xie et al 2021). Liu et al (2021) standardized a flow cytometry based method for S. aureus detection in milk and milk powder. In this methodology, fluorescently labeled antibodies and propidium iodide were used for selective detection of viable S. aureus.…”

Section: S Aureus -Traditional and Rapid Identification Approachesmentioning

confidence: 99%

Staphylococcus aureus: significance, control and rapid detection across milk chain

Wandhare

Singh

Kaur

et al. 2021

IJDS

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Staphylococcus aureus is a major pathogen of public health concern with dominant role in food poisoning outbreaks, nosocomial and community-acquired infections, and also in bovine mastitis. Milk being a rich nutritious source for growth and proliferation of pathogenic species is prone to bacterial contamination, which can lead to spoilage and food poisoning. Toxin production, heat resistance, biofilm formation, antibiotic and lysozyme resistance are among the characteristics that contribute to S. aureus pathogenicity. S. aureus and its enterotoxins in food remains a daunting challenge, despite global efforts towards its mitigation. There is a need for rapid and costeffective on-site detection of S. aureus in milk to prevent its transmission. The article outlines the significance of S. aureus in milk chain, its ability to adapt to environmental stresses, possible mitigation and rapid detection strategies; that may help to curtail its presence in milk chain and linked food poisoning episodes; besides ensuring food quality and consumer safety.

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Faster Detection ofStaphylococcus aureusin Milk and Milk Powder by Flow Cytometry

Cited by 13 publications

References 24 publications

Rapid and Accurate Quantification of Viable Lactobacillus Cells in Infant Formula by Flow Cytometry Combined with Propidium Monoazide and Signal-Enhanced Fluorescence In Situ Hybridization

Rapid and Accurate Quantification of Viable Lactobacillus Cells in Infant Formula by Flow Cytometry Combined with Propidium Monoazide and Signal-Enhanced Fluorescence In Situ Hybridization

Oxygen Sensor-Based Respirometry and the Landscape of Microbial Testing Methods as Applicable to Food and Beverage Matrices

Staphylococcus aureus: significance, control and rapid detection across milk chain

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