A Comparison of the Mechanical Properties of Different Bacterial Species

Shiu, CC; Zhang, Z.; Thomas, C. R.

doi:10.1007/0-306-46888-3_11

Cited by 6 publications

(8 citation statements)

References 11 publications

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“…Another study tested E. coli K12 inactivation with the combined effect of high‐pressure homogenization and Nisin in juice, and no significant differences ( p > .05) were found between the treatments with and without Nisin (Pathanibul et al, 2009). It has been found that gram‐negative bacteria are generally more susceptible to damage by mechanical stress, such as sonication, as compared to gram‐positive bacteria (Shiu et al, 2002). Thus, it is believed that the significant interaction obtained is due to the higher susceptibility to damage of gram‐negative bacteria to sonication rather than the presence of Nisin.…”

Section: Resultsmentioning

confidence: 99%

Synergistic effect of high‐intensity ultrasound, UV‐A light, and natural preservatives on microbial inactivation in milk

Hales

Walsh

Bastarrachea

2022

Food Processing Preservation

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Synergistic effect between high-intensity ultrasound (HIU), UV-A light, and natural antimicrobials on microbial inactivation in milk was studied. Milk with either εpoly(lysine) or Nisin was subjected to HIU (30 s) and then to UV-A light (15 min).Statistically significant treatments were stored at 4 or 25°C for 24 hr. Escherichia coli K12 was reduced by ~2 logarithmic cycles with ε-poly(lysine). During storage, there was decline in microorganisms at 4°C and no detectable load at 25°C. E. coli K12 was reduced by ~1 logarithmic with Nisin, and during storage, the population decreased at 4°C and increased at 25°C. Listeria innocua L2 was not affected by ε-poly(lysine), but it was reduced by ~4 logarithmic cycles with Nisin. During storage, L. innocua decreased after 24 hr at 4°C, and increased at 25°C. The treatments caused slight changes in color and pH. Novelty impact statement:In this study, we confirmed that a short exposure to highintensity ultrasound and UV-A light in combination with natural preservatives can serve as an aid to inactivate gram-positive and gram-negative microorganisms in milk.This combination can result in a reduction of up to 99.99% in the initial microbial population, which can be reduced even further if it is followed by a storage time of 24 hr under refrigeration. These treatments also seem to have marginal effect on the color and pH of milk.

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Section: Resultsmentioning

confidence: 99%

Synergistic effect of high‐intensity ultrasound, UV‐A light, and natural preservatives on microbial inactivation in milk

Hales

Walsh

Bastarrachea

2022

Food Processing Preservation

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“…The cell walls of Gram-negative bacteria are weaker than those of Gram-positive bacteria. Gram-negative bacteria are more susceptible to disintegration by mechanical stress [17], though Gram-negative bacteria are more resistant to antibiotics because of the outer membrane, which contributes to the reduced cell permeability [18]. It is possible that the rinsing step at 80˚C is more detrimental to Gramnegative bacteria compared to Gram-positive bacteria.…”

Section: Classification Of the Isolated Bacteriamentioning

confidence: 99%

Evaluation of contaminated bacteria inside door- and conveyor-types of dishwashers used in food service facilities

2020

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Dishwashers are one of the sources of bacterial contamination in dishes despite the fact that they comprise extreme environments due to the high temperature, high pH, and the presence of detergents during their operation. In this study, viable bacteria were isolated from 6 door-type and 8 conveyor-type dishwashers that were being used in food service facilities. Each door-and conveyortype dishwasher was divided into 6 and 9 sections respectively. Thermophilic bacteria, which grow at 60˚C, were obtained from 5 sections of door-type dishwashers, but obtained from one section of conveyor-type dishwashers tested. The 16S rRNA sequences of the cultured isolates revealed that fewer Gram-negative bacterial strains were found in door-type dishwashers than in conveyor-type dishwashers. The most frequently identified bacterial species in the samples tested were spore-forming bacteria, such as Bacillus and Anoxybacillus species. This study highlights the vulnerabilities presented by dishwashers used in food service facilities.

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“…The small size of prokaryotes, in comparison with larger eukaryotic cells, was a considerable obstacle in the development of methods for directly measuring their mechanical properties [47], solved largely by FS methods now routinely used. Cellular mechanical strength mainly relies on the outermost layers, such as the cell wall, envelope, or membrane, in addition to internal structural components such as the cytoskeleton.…”

Section: Viscoelastic Cellular Components and Super Structuresmentioning

confidence: 99%

“…Thus lipopolysaccharides, peptidoglycan thickness, the bound form of the peptidoglycanlipoprotein complex and stabilizing cations all play an important role in maintaining viscoelasticity [19]. A micromanipulation study using optical fiber probes to test bursting strength also showed E. coli to have a weaker envelope than the Gram-positive Staphylococcus epidermis, more susceptible to mechanical stress [47]. Researchers thus attribute the elastic component of the cell envelope to the peptidoglycan layer and the viscous component to the liquid phase of the membranes [19,45].…”

Section: Cell Envelopes Walls and Membranesmentioning

confidence: 99%