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Preservative Resistance
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Because the mechanism for the development of antimicrobial resistance is not fully understood for all of the different types of preservatives that are commonly used by the cosmetic and personal care industry, there are several steps that need to be in place in order to prevent their generation. One prevention step is to ensure that all of the cleaning and sanitization procedures of manufacturing equipment are validated and followed correctly at all times to prevent product residuals and rinse water remains in manufacturing equipment before a new finished product batch is compounded. A second prevention step is that the use of sub-lethal or sub-inhibitory concentrations of preservatives be avoided for usage in a product formulation in order to prevent either preservative adaptation or mutation by a contaminating microorganism. The concentration of a preservative in a product formulation must be above the MIC and/or MLC in which there would be either static or cidal activity against contaminating microorganisms (74). The third prevention step is the use of other hurdle technology factors to prevent the growth of microorganisms. Included are product formulation factors such as a low or high pH, hostile manufacturing temperatures, low water activity, and modified finished product packaging that could prevent the introduction of microorganisms during consumer usage. The fourth prevention step involves the design of a preservative system for a susceptible product formulation to include the several different preservative system components to prevent the generation of a selective pressure and preservative- resistant strains to a single preservative system component of limited efficacy. The fifth prevention step is to use physical disinfectant methods such as heat in place of chemical sanitizers that may generate resistant isolates in which the active ingredient of the disinfectant is the same as the preservative in a product formulation. If a chemical disinfectant has to be used for sanitizing manufacturing equipment surfaces, it is recommended that a stronger disinfectant be used that has an active ingredient such as chlorine, peracetic acid, or glutaraldehyde to prevent the survivability and proliferation of resistant microorganism in a product formulation.
Microbially-derived cocktail of carbohydrases as an anti-biofouling agents: a ‘green approach’
Published in Biofouling, 2022
Harmanpreet Kaur, Arashdeep Kaur, Sanjeev Kumar Soni, Praveen Rishi
Compared to planktonic cells, biofilms are extremely recalcitrant to antimicrobials due to physical impedance, slow diffusion, enzymatic inactivation of drugs, and lowered metabolic rates in biofilm-associated cells (Lewis 2012; Roy et al. 2018). Therefore, microorganisms associated with biofilms are more likely to regenerate, leading to contamination or infection at the same location or on adjacent sterile surfaces. The control of biofilms does not necessarily require the direct killing of microorganisms but can be directed toward the dispersal of the biofilm matrix followed by antimicrobial action of different agents like antibiotics. The combined action can help reverse biofilm to the planktonic state, which is far easier to remove. Thus, harmoniously combining enzymes with various antimicrobial agents is a possible approach (Nahar et al. 2018). 'Hurdle Technology' refers to the combination of two or more control strategies that can potentially overcome the limitations of a single-strength approach, as shown in Fig. 5 (Toushik et al. 2020; Zhu et al. 2021). For example, α-amylase or β-glucanase combined with cationic surfactant cetyltrimethylammonium bromide (CTAB) exhibited a synergistic effect, enhancing the reduction of P. fluorescens biofilms. However, the combination of CTAB and protease reduced this activity, leading to an antagonistic effect (Araújo et al. 2017).Various studies have brought attention to the use of enzymes in conjunction with other antimicrobial therapies, physical or chemicals, as discussed in Table 3 (Mnif et al. 2020; Yuan et al. 2020).
A review on inactivation methods of Toxoplasma gondii in foods
Published in Pathogens and Global Health, 2018
Adel Mirza Alizadeh, Sahar Jazaeri, Bahar Shemshadi, Fataneh Hashempour-Baltork, Zahra Sarlak, Zahra Pilevar, Hedayat Hosseini
The results of research clearly indicates that food contaminated with all structural forms of T. gondii (tachyzoites, bradyzoites, oocysts, sporocysts, sporozoites and enteroepithelials) pose a risk to public health if consumed in raw or undercooked meat, unpasteurized milk, raw vegetables and water contaminated with T. gondii oocysts from cat feces. Food preservation technologies are based on the prevention if the growth, the inactivation or killing of the microorganism. This review describes all appropriate and applicable methods and their parameters for effective inactivation, prevention or killing of T. gondii in different types of food and tissues. There are other ways to inactivate T. gondii that have not been the focus of research thus far. We therefore suggest that further research should evaluate the treatment of food samples with novel thermal or non-thermal technologies and chemical and biochemical processing methods for the inactivation of T. gondii. These include PEF, PLT, CP, pulsed UV, tumbling and injection, enzymes, active packaging materials and Hurdle technology. Many technological, economic and regulatory barriers must to be overcome before the food supply can benefit from these methods.
Hurdle technology based on the use of microencapsulated pepsin, trypsin and carvacrol to eradicate Pseudomonas aeruginosa and Enterococcus faecalis biofilms
Published in Biofouling, 2022
Samah Mechmechani, Adem Gharsallaoui, Khaled El Omari, Alexandre Fadel, Monzer Hamze, Nour-Eddine Chihib
However, due to the complexity of biofilms, the single use of enzymes is often insufficient for eradicating an entire biofilm (Yuan et al. 2021). In addition, treatment with enzymes may result in the contamination of other areas with dispersed bacteria, thus allowing the redevelopment of neoformed biofilms. Therefore, it is essential to use a combination of enzymes and other active agents (Hurdle technology) to attack different targets within biofilms (EPS matrix and biofilm cells) (Borges et al. 2020). The combination of enzymes and biobased antimicrobials would provide a promising approach to control biofilms. The enzymes destroy and destabilize the EPS matrix of the biofilm and thus the bacterial cells can be more effectively killed by the antimicrobials. It has been reported that the combined use of EPS-degrading enzymes and biocides is a promising approach for potential applications in biofilm control (Wang et al. 2016; Rodríguez-López et al. 2017; Zhou et al. 2018; Lim et al. 2019; Baidamshina et al. 2021). Currently, biobased antimicrobial substances have attracted attention due to their high efficacy, safety, and non-toxic effects (Nazzaro et al. 2013). Carvacrol, a monoterpenoid phenol, is a major component of Origanum vulgare essential oil (EO) and can be found in several other EOs such as Thymus vulgaris and Satureja bachtiarica (Trevisan et al. 2018). Several studies have demonstrated its antibiofilm activity on various surfaces (Amaral et al. 2015; Trevisan et al. 2018; Walczak et al. 2021). However, essential oils are generally volatile and highly vulnerable to photolysis and oxidation. The low water solubility of these active compounds can also minimize their antimicrobial efficacy (Gharsallaoui et al. 2007; Shan et al. 2007; Liu et al. 2018). In addition, the activity of enzymes is highly influenced by environmental factors, such as temperature and pH. Another disadvantage of using enzymes is their self-degradation, which causes their instability (Cordeiro and Werner 2011).