China
Africa
Explore chapters and articles related to this topic
Scombrotoxin
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Apart from temperature control, inhibition or inactivation of HPB can be done by either chemical or physical means. The effect of antimicrobials/preservatives, such as clove, sodium chloride, essential oils, and chlorine, has been studied with variable results. The addition of 0.5% clove delayed growth and amine production of Enterobacter aerogenes and the combination of 2% NaCl and clove completely inhibited growth and amine production in mackerel muscle broth (112). Similarly, oregano oil (0.05%) was found to reduce the growth of P. phosphoreum and extend the shelf life of cod fillets (113). Taylor et al. reported that 0.5% sorbate inhibited growth of M. morganii and Klebsiella pneumoniae; however, sodium hexametaphosphate and sodium polyphosphate and sodium chloride did not inhibit growth and histamine production. Bjornsdottir-Butler et al. (114) found that 7% phosphate treatment of tuna and mahi-mahi significantly reduced growth and histamine production of four histamine-producing bacteria. Similarly, Hu et al. (115) found that potassium sorbate and sodium diacetate reduced histamine formation in chub mackerel dipped in 0.5% solution. Research has shown that 20%–80% CO2-modified atmosphere may inhibit the formation of histamine (52,116,117). The main challenge of the use of these antimicrobial treatments is that they may have undesirable effects on the appearance and taste of the product.
Microbial Monitoring of a Manufacturing Facility
Published in Philip A. Geis, Cosmetic Microbiology, 2020
There are essentially two swab methods for sampling equipment surfaces: qualitative (presence or absence) and quantitative. To perform both a qualitative and a quantitative surface swab method, a sterile swab is moistened with sterile diluent that may contain a sanitizer/disinfectant neutralizing agent. The moistened swab is used to wipe a given equipment surface dimension (e.g., 25 cm2 or 2-inch × 2-inch area) by reversing the direction between successive stokes while rotating the swab between the fingers. This can be facilitated with the use of a sterile template cut to these dimensions. In a qualitative method, the used swab is streaked across the surface of a microbial growth agar in a Petri dish or immersed in a liquid microbial growth medium. After incubation, streaked agar Petri dishes or liquid microbial growth media are examined for the presence or absence of microbial growth. In a quantitative method, the used swab can be placed into a solution to remove the collected microorganisms by either vortexing or shaking. A calcium alginate swab can be used in a quantitative method. After taking a surface sample, the used calcium alginate swab is dissolved in either a 1% sodium citrate solution or in a 1% sodium hexametaphosphate in ¼-strength Ringers solution to free microorganism that had been collected in the fibrous strands of the calcium alginate swab. Aliquots of the solution are either pour plated by using the appropriate microbial growth agar or filtered through a membrane filter that is transferred to either a microbial growth broth–impregnated pad or to a Petri dish with a microbial growth agar. After incubation, the number of colonies for each sampling site is counted and reported as the number of CFU per swab or surface area.
Effect of sodium hexametaphosphate and fluoride on dual-species biofilms of Candida albicans and Streptococcus mutans
Published in Biofouling, 2021
Thayse Yumi Hosida, Juliano Pelim Pessan, Thamires Priscila Cavazana, Caio Sampaio, Douglas Roberto Monteiro, Alberto Carlos Botazzo Delbem
The association of microorganisms within pathogenic biofilms may contribute to the resistance to conventional therapies (Cepas and Soto 2020), which has encouraged studies to assess alternative antimicrobial agents with the potential to interfere with biofilm formation. Sodium hexametaphosphate (HMP) consists of an inorganic cyclophosphate that exhibits antimicrobial activity by binding to the cell wall of Gram-positive bacteria, increasing its permeability (Shibata and Morioka 1982; Vaara 1992). The combination of HMP with fluoridated dentifrices has marked synergistic effects on enamel de- and re-mineralization processes (da Camara et al. 2014, 2015, 2016; Danelon et al. 2019; Garcia et al. 2019). Studies have also shown that the association of HMP with fluoride (F) in dentifrices decreased the production of extracellular polysaccharides in biofilms exposed to sucrose (da Camara et al. 2015; Garcia et al. 2019).
Sodium trimetaphosphate and hexametaphosphate impregnated with silver nanoparticles: characteristics and antimicrobial efficacy
Published in Biofouling, 2018
Carla Corrêa Mendes-Gouvêa, Jackeline Gallo do Amaral, Renan Aparecido Fernandes, Gabriela Lopes Fernandes, Luiz Fernando Gorup, Emerson Rodrigues Camargo, Alberto Carlos Botazzo Delbem, Debora Barros Barbosa
Nanocomposites were synthesized based on the protocol proposed by Miranda et al. (2010), with some modifications. The synthesis was carried out in an alcoholic medium (isopropanol) using sodium borohydride (NaBH4, Sigma-Aldrich, St Louis, MO, USA) as a reducing agent. Suspensions containing sodium trimetaphosphate (TMP, Sigma-Aldrich, CAS 7785-84-4) or sodium hexametaphosphate (HMP, Sigma-Aldrich, CAS 68915-31-1), fluoride (NaF, Merck, Darmstadt, Germany), and silver nitrate (AgNO3, Merck) were prepared in the presence of a surfactant (ammonium salt of polymethacrylic acid (NH-PM), Polysciences, Inc., Warrington, PA, USA). AgNO3 was employed at 1% or 10% of the phosphate weight. The molar proportions between phosphates and fluoride was 1.2:1 TMP/NaF or 0.62:1 HMP/NaF, and between silver ions (Ag+) and NaBH4 it was 1:1.26. Samples were dried overnight at 70°C. AgNP with no polyphosphates was also synthesized.
Synthesis, characterization and anticancer activity of vincristine loaded folic acid-chitosan conjugated nanoparticles on NCI-H460 non-small cell lung cancer cell line
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Naresh Kumar, Raj Kumar Salar, Minakshi Prasad, Koushlesh Ranjan
Different sized nanoparticles with spherical shape and rough surface were observed by scanning electron microscopy (Fig. 3). However, there were difference in the size of nanoparticles as compared with dynamic light scattering (DLS) due to different techniques used for preparation of nanoparticles for analysis. The nanoparticles in 4:25 formulation looked more rough in appearance, which might be due to maximum loading of vincristine in these. In contrast, Panwar et al. [28] observed smooth and spherical shaped ferulic acid-loaded chitosan nanoparticles and checked anticancer activity against ME-180 human cervical cancer cell lines. They observed significant inhibition in ME-180 cells and concluded that these nanoparticles can be used to treat cervical cancer. Anitha et al. [29] also observed spherical morphology of curcumin-loaded N,O-carboxymethyl chitosan nanoparticles and checked anticancer activity against normal (L929) and breast cancer cell line (MCF-7). The authors reported non-toxicity of nanoparticles against L929 cells, whereas enhanced toxicity was found against MCF-7 cells. In another report, Mehrotra et al. [30] observed spherical shaped and smooth surfaced lomustine loaded chitosan sodium tripolyphosphate and chitosan-sodium hexametaphosphate nanoparticles.