Comparison of predicted and impedance determined growth of Listeria innocua in complex food matrices

Nyhan, Laura; Johnson, Nicholas; Begley, Máire; O'Leary, Padraic; Callanan, Michael

doi:10.1016/j.fm.2019.103381

Cited by 6 publications

(3 citation statements)

References 37 publications

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“…Impedance/capacitance [ 132 – 137 ] and potentiometry (especial pH-metry) [ 138 – 140 ] are usually applied because the growth of microbes changes the electrical properties and the strength of the acids. Indirect conductivity can be used to measure CO 2 production as an indicator of microbial growth [ 141 , 142 ].…”

Section: Emerging Alternativesmentioning

confidence: 99%

“…Thus, conductimetric technology can be used to indirectly monitor microbial growth. The Callanan group introduced an indirect conductivity method to study the bacterial growth in complex food matrices [ 141 , 142 ]. The linearity of conductivity responses in selected food products was investigated with good correlation ( R 2 ≥ 0.84) between inoculum levels and times to detection.…”

Section: Emerging Alternativesmentioning

confidence: 99%

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Analytical methods for assessing antimicrobial activity of nanomaterials in complex media: advances, challenges, and perspectives

Zhang

Hou

et al. 2023

J Nanobiotechnol

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Assessing the antimicrobial activity of engineered nanomaterials (ENMs), especially in realistic scenarios, is of great significance for both basic research and applications. Multiple analytical methods are available for analysis via off-line or on-line measurements. Real-world samples are often complex with inorganic and organic components, which complicates the measurements of microbial viability and/or metabolic activity. This article highlights the recent advances achieved in analytical methods including typical applications and specifics regarding their accuracy, cost, efficiency, and user-friendliness. Methodological drawbacks, technique gaps, and future perspectives are also discussed. This review aims to help researchers select suitable methods for gaining insight into antimicrobial activities of targeted ENMs in artificial and natural complex matrices.

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Section: Emerging Alternativesmentioning

confidence: 99%

Section: Emerging Alternativesmentioning

confidence: 99%

Analytical methods for assessing antimicrobial activity of nanomaterials in complex media: advances, challenges, and perspectives

Zhang

Hou

et al. 2023

J Nanobiotechnol

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“…Even though listeriosis is a rare disease, it has a high case-fatality rate of 20–30%, making L. monocytogenes a leading foodborne pathogen associated with human mortality [ 16 ]. Unexpectedly, pathogenic L. monocytogenes is genetically closely related to L. innocua , a non-pathogenic Listeria species [ 17 , 18 ]. A whole-genome comparison of L. monocytogenes EGDe (serovar 1/2a) and L. innocua CLIP 11262 strains by Glaser et al [ 19 ] revealed similarities between the chromosomes of the two strains.…”

Section: Introductionmentioning

confidence: 99%

Identification of Listeria species and Multilocus Variable-Number Tandem Repeat Analysis (MLVA) Typing of Listeria innocua and Listeria monocytogenes Isolates from Cattle Farms and Beef and Beef-Based Products from Retail Outlets in Mpumalanga and North West Provinces, South Africa

Manqele

Gcebe

Pierneef³

et al. 2023

Pathogens

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In this study, Listeria isolates (214) were characterized as follows: L. innocua (77.10%), L. monocytogenes (11.21%), L. welshimeri (5.61%), L. grayi (1.40%), L. seeligeri (0.93%), and L. species (3.73%) that were not identified at the species level, from beef and beef based products from retail and farms in Mpumalanga and North West provinces of South Africa. MLVA was further used to type Listeria innocua isolates (165) and Listeria monocytogenes isolates (24). The L. monocytogenes isolates were also serogrouped using PCR. The MLVA protocol for L. monocytogenes typing included six tandem repeat primer sets, and the MLVA protocol for L. innocua included the use of three tandem repeats primer sets. The L. monocytogenes serogroups were determined as follows: 4b-4d-4e (IVb) (37.50%), 1/2a-3a (IIa) (29.16%), 1/2b-3b (IIb) (12.50%), 1/2c-3c (IIc) (8.33%), and IVb-1 (4.16%). MLVA could cluster isolates belonging to each specie, L. monocytogenes, and L. innocua isolates, into MLVA-related strains. There were 34 and 10 MLVA types obtained from the MLVA typing of L. innocua and L. monocytogenes, respectively. MLVA clustered the L. monocytogenes isolates irrespective of sample category, serogroups, and geographical origin. Similarly, the L. innocua isolates clustered irrespective of meat category and geographical origin. MLVA was able to cluster isolates based on MLVA relatedness. The clustering of isolates from farms and retailers indicates transmission of Listeria spp. MLVA is an affordable, simple, and discriminatory method that can be used routinely to type L. monocytogenes and L. innocua isolates.

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Detection of Biofilm on Water Supply Technical Materials with the Application of an Impedance Sensor

2022

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In favourable environmental conditions microorganisms can adhere to surfaces and reproduce, forming biofilm. Such a structure causes biodeterioration, i.e. biological degradation of technical materials. The issue is of high importance in the case of distribution of treated water to end-point consumers. An important factor determining the formation of biofilm is the type and character of the surface which can stimulate or inhibit its growth. The article presents innovative results of research involving measurement of growth of biofilm on technical materials used for the construction of water supply networks by means of an impedance sensor. The research was conducted at a laboratory scale continuously for 6 months, reflecting actual conditions occurring in water distribution systems. After half a year culture of environmental microorganisms in the bioreactor, an almost 100% increase in the value of relative impedance was recorded by means of a sensor placed inside the bioreactor. A comparison of the surface coverage of technical materials and the sensor with bacteria (fluorescence in situ hybridization) showed that the sensor could be used for technical materials made of polybutylene, polypropylene, and polyvinyl chloride. Observations (scanning electron microscopy) of the surface of the plastics used to build the water supply network pipes (new materials, with biofilm present, and after detaching the biofilm) showed significant changes in the structures of the materials due to biofilm formation. The largest changes in the structure were observed on the polyethylene and polypropylene surfaces. The proposed sensor could be applied in the measurements of biofilm adhesion to selected technical materials.

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Comparison of predicted and impedance determined growth of Listeria innocua in complex food matrices

Cited by 6 publications

References 37 publications

Analytical methods for assessing antimicrobial activity of nanomaterials in complex media: advances, challenges, and perspectives

Analytical methods for assessing antimicrobial activity of nanomaterials in complex media: advances, challenges, and perspectives

Identification of Listeria species and Multilocus Variable-Number Tandem Repeat Analysis (MLVA) Typing of Listeria innocua and Listeria monocytogenes Isolates from Cattle Farms and Beef and Beef-Based Products from Retail Outlets in Mpumalanga and North West Provinces, South Africa

Detection of Biofilm on Water Supply Technical Materials with the Application of an Impedance Sensor

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