Use of microbiological indicators for assessing hygiene controls for the manufacture of powdered infant formula

Microbiological testing for various indicator microorganisms is used extensively as a means of verifying the effectiveness of efforts to ensure the microbiological quality and safety of a wide variety of foods. However, for each use of an indicator organism the underlying scientific assumptions related to the behavior of the target microorganism, the characteristics of the food matrix, the details of the food manufacturing processes, environment, and distribution system, and the methodological basis for the assay must be evaluated to determine the validity, utility, and efficacy of potential microbiological indicator tests. The recent adoption by the Codex Alimentarius Commission of microbiological criteria for powdered infant formulae and related products provides an excellent example of an evidence-based approach for the establishment of consensus microbiological criteria. The present article reviews these criteria and those of various national governments in relation to emerging principles for the evidence-based establishment of effective indicator organisms.     

Dowicil 200 Stability test: chemical and microbiological studies

The stability of the formaldehyde-releaser preservative Dowicil 200 has been investigated. The studies were carried out on cosmetic emulsions preserved with different concentrations of Dowicil 200, stored in the dark at 45°C or 25°C. The degree of microbiological activity was tested with respect to S. aureus, P. aeruginosa, E. coli and A. niger using the agar diffusion and challenge tests. The chemical stability was evaluated by HPLC in the reverse phase mode. A significant preservative instability was observed.     

Characterisation of reused osmotic solution as ingredient in new product formulation

Osmotic dehydration (OD) with sugar solutions has been used in fruit preservation but part of the process's economic viability depends on the possibility of reusing the osmotic solution (OS) in successive dehydration cycles. Despite the increase in water content, OD promotes OS enrichment in certain water-soluble natural components extracted from fruits, such as vitamins and minerals. For this reason, to recycle it for new food formulation seems to be an attractive alternative. In this paper, changes in soluble solids, a_w, pH, electrical conductivity, density, viscosity and colour in osmotic solution used for kiwifruit dehydration in function of the ratio osmotic solution/fruit (20:1, 10:1 and 5:1) and the number of cycles (up to 10) have been studied. Microbiological analysis of OS and fruit compositional changes were also studied. The results show that during OD likewise water interchange between fruit and OS, a flow of mineral salts and sugar from the fruit to the OS, is produced. Nevertheless OS changes associated to the OD of kiwifruit under the conditions of this study allow OS reuse for at least 10 cycles without any problems related to fruit dehydration level, colour fruit changes, or considerable microbiological contamination.     

Transparent xyloglucan–chitosan complex hydrogels for different applications

This article reports the oxidation of xyloglucan and its transparent hydrogel formation with chitosan. The xyloglucan was oxidized by using periodate and the oxidized xyloglucan was blended with chitosan which formed versatile irreversible transparent hydrogels. The oxidation of xyloglucan and the covalent linkage between oxidized xyloglucan and chitosan was established by FTIR analysis. The morphological analyses of gel by SEM and TEM confirmed the evolution of nanosphere structure of xyloglucan (100 nm) linked with elongated and fibrous network of chitosan, besides; the gels formed are in self-assembled nature. Gelation property of xyloglucan–chitosan gel at different pH and concentration were examined by rheological tests. Incorporation of flavours and salts did not alter its gel nature. This complex gel possesses good thermal properties compared to the native xyloglucan. In addition, its antimicrobial and texture properties are very promising and this non-toxic, renewable gel will find extensive use in food and cosmetic applications.     

Essential oil composition and antimicrobial activity of Origanum majorana L. extracts obtained with ethyl alcohol and supercritical carbon dioxide

Volatile components of marjoram (Origanum majorana L.) essential oil obtained by hydrodistillation and extracts obtained by solvent extraction with ethyl alcohol and supercritical fluid extraction (SFE) were investigated. The compositions of volatile compounds in essential oil, ethanolic and SFE extracts were determined by GC and GC–MS. The antimicrobial properties of marjoram solvent extracts were investigated with microbiological tests against food borne fungi and bacteria strains. Extracts obtained by SFE at high pressure and temperature showed significantly stronger antimicrobial properties in comparison to the slight inhibitory effects of the ethanolic extract. The results support the notion that extracts obtained by SFE might have a role as flavourings and natural colourants as well as use as preservatives in food and cosmetic systems.     

Recalls of microbiologically contaminated cosmetics in EU from 2005 to May 2008

The Rapid Alert System for non‐food consumer products in the EU (RAPEX) notifies each week the member countries on dangerous products sold in the EU. Microbiological contaminated cosmetics pose a potential health risk and are recalled from the market. This study investigated the number of recalled microbiological contaminated cosmetics products in the RAPEX database from 2005 to until week 17 in 2008. A total of 173 cosmetic products were recalled in the period, 24 were contaminated and the most frequently found micro‐organism was the pathogenic Pseudomonas aeruginosa. It appears that the number of contaminated cosmetic products could be two to three times higher in 2008 compared to 2007. The recalled products were manufactured in 17 different countries and only one company had more than one product recalled. It is important to keep monitoring the cosmetic products for contamination because an increasing number of products are recalled each year, and the majority is contaminated with potential pathogenic micro‐organism. More knowledge on the reasons for the contamination is needed.     

Preservative systems containing essential oils in cosmetic products

The aim of this study was to evaluate the antimicrobial activity of selected essential oils ( Laurus nobilis , Eucalyptus globulus and Salvia officinalis ), both alone and in combination, in cosmetic preparations characterized by an increasing risk of microbial contamination, i.e. an O/W skin cream, a hydrogel and a non-alcoholic hydrolyte. Their potential synergistic effect in combination with the usual cosmetic preservatives at low concentrations (up to 200-fold less than usual) was also investigated.     

Chemical stability and microbiological reply of preservative systems in cosmetics: a direct correlation

The results of a chemical/microbiological comparative study on different preservative mixtures are reported. The aim of the investigation was to ascertain whether there was a correlation between chemical stability and microbiological activity.
The studies were carried out directly in cosmetic emulsions preserved with different mixtures of Prevan, Bronopol, Germall 115 and Kathon CG.
The degree of microbiological activity was tested with respect to E. coli, Ps. aeruginosa, Asp. niger, S. aureus using the agar diffusion test, over a period of 400 days.
The chemical behaviour of the different mixtures was evaluated by HPLC in reverse phase mode. The emulsion samples were directly injected after dilution with a THF/H₂O) (9/1) solvent mixture.     

The influence of surface treatment on hydrophobicity, protein adsorption and microbial colonisation of silicone hydrogel contact lenses.

PURPOSE: To evaluate the influence of surface treatment of silicone-hydrogel CL on lens hydrophobicity, protein adsorption and microbial colonisation by studying several silicone hydrogel contact lenses (CL) with and without surface treatment. The lenses used in this study were Balafilcon A, Lotrafilcon A, Lotrafilcon B and Galyfilcon A. A conventional hydrogel CL (Etafilcon A) was also tested. METHODS: Hydrophobicity was determined through contact angle measurement using the advancing type technique on air. The type and quantity of proteins adsorbed were assessed through SDS-PAGE and fluorescence spectroscopy, respectively. Microbial colonisation was studied by removing the microbes from the lenses through sonication, and counting the colony-forming units on agar plates. RESULTS: Regarding hydrophobicity, both surface and non-surface-treated silicone hydrogel CL were found to be hydrophobic, and the conventional hydrogel CL was found to be hydrophilic. Concerning protein adsorption, different protein profiles were observed on the several lenses tested. Nevertheless, the presence of proteins with the same molecular weight as lysozyme and lactoferrin was common to all lenses, which is probably related to their abundance in tears. In terms of total protein adsorption, silicone hydrogel CL did not exhibit any differences between themselves. However, the conventional hydrogel Etafilcon A adsorbed a larger amount of proteins. Regarding microbial colonisation, Balafilcon A exhibited the greatest amount of colonising microbes, which can be due to its superior hydrophobicity and higher electron acceptor capacity. CONCLUSION: This study suggests that silicone hydrogel lenses adsorb a lower amount of proteins than the conventional hydrogel lenses and that this phenomenon is independent of the presence of surface treatment. Concerning microbial colonisation, the surface treated Balafilcon A, exhibited a greater propensity, a fact that may compromise the lens wearer's ocular health.     

Hydroxy Dimethoxybenzyl Malonate: A Novel Anti-(Photo)ageing Concept

Ideally, anti-(photo)ageing concepts should provide maximum efficacy, perfect stability and cosmetic (formulation) elegance. The need for high efficacy paired with excellent stability appeared contradictive but was resolved by designing complete redox systems rather than antioxidants alone. We here introduce a new class of cosmetic redox pairs, each comprising the initial antioxidant plus its oxidation product. The chemical properties of the oxidation product are the key to enabling the system to maintain or even increase its initial efficacy. A series of antioxidant tests were used to carefully characterize single redox pair components for comparison with traditional antioxidants such as vitamin C and E derivatives (DPPH, lipid and TEAC assays). Kinetic studies on the photobehaviour of a selected redox pair were carried out in cosmetic emulsions with solar simulation and monitored by UV spectroscopy and high performance liquid chromatography. Hydroxy dimethoxybenzyl malonate (HDBM) is a pure transparent cosmetic oil. It shows excellent cosmetic stability coupled with extraordinary antioxidant properties. This controlled activity can be explained well by the presence of its oxidation product hydroxy dimethoxybenzylidene malonate (HDBM ox ), which provides ongoing antioxidant activity plus excellent UVA absorbing properties. The redox pair described here provides the advanced on-demand benefit of a non-UV-absorbing photoprotector that is converted into its UV-absorbing equivalent upon light exposure.     

Encapsulated probiotic spores as a fortification strategy for development of novel functional beverages

The potential of polysaccharide matrix for encapsulation and delivery of probiotic spores of B. coagulans was evaluated for the first time in this study. Different concentrations of gellan and κ-carrageenan were explored for fabrication of hydrogel beads, which were then used to encapsulate probiotic spores. The study indicated that these beads exhibited minimal leaching under acidic conditions However, a sustainable release pattern was observed at neutral and alkaline pH. It was also found that leaching of spores followed a similar pattern when added to commercially available fruit juice and coconut water. In vitro digestion studies revealed that these beads prevented leaching and maintained the viability of spores under gastric condition, while promoted its release in intestinal phase. It was noteworthy that under ambient conditions leaching of 30% is observed until 24 h, however, ~100% of the encapsulated spores were released in simulated intestinal phase. Moreover, it was inferred from the accelerated spoilage studies that fruit juice and coconut water fortified with spore-loaded hydrogel beads could remain stable for at least three weeks. This comprehensive microbiological study could pave the way for developing novel functional beverages.     

Contact lens-associated chemical burn.

We present the case of a young man who presented as an ophthalmic casualty after inserting a pair of bizarre-effect cosmetic hydrogel contact lenses while in a night-club. He failed to follow the manufacturer's guidelines and inserted the lenses before neutralising the storage solution. On presentation he was found to have bilateral corneal epithelial defects which required hospital treatment for 4 days. He appears to have suffered no long-term sequelae.     

Antibacterial PET-Silk fabric containing Salvia officinalis extract

In this study, novel PET-Silk fabric is introduced via finishing PET fabric with silk hydrogel and Salvia officinalis extract. The silk hydrogel was prepared from waste silk; morphology and chemical structure were evaluated by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy methods. The results indicated the 3D porous network and crystalline structure of hydrogel. The polyester fabric was finished with prepared hydrogel. Contact angle and water uptake of modified fabric were assessed. S. officinalis extract was used as an antibacterial agent. Results of antibacterial tests confirmed a remarkable antibacterial effect of finished fabrics with the extract.     

Gamma irradiation,rheological and microbiological analysis of cosmetic products

In this study, we aimed to use gamma irradiation for decontamination of cosmetic product (gel) achieve the acceptable microbiological limits. Cosmetic product vials were irradiated (10–100 kGy) and physicochemical, microbiological and biological properties of these samples were evaluated in normal conditions. Decontamination dose for all samples was found to be about 10 kGy or below. A pseudoplastic feature was induced in the gel after irradiation suggesting a large applicability of gamma radiation to this purpose.     

Application of molecularly imprinted hydrogel for the preparation of lactose‐free milk

BACKGROUND: A variety of lactose imprinted hydrogels were prepared and their binding properties were studied in comparison with blank non‐imprinted hydrogel. Methacrylamide and ethylene glycol dimethacrylate were used as functional monomer and cross‐linker, respectively. Dimethylsulfoxide was also applied as polymerisation solvent. RESULTS: Different template/monomer ratios were studied and the optimised imprinted hydrogel (MIP₂), with a lactose/methacrylamide ratio of 1:8, was selected in a rebinding test. In Scatchard analysis of MIP₂‐lactose interactions, the dissociation constant and maximum binding sites were 0.33 mmol L^?1 and 67.76 µmol g^?1 hydrogel, respectively. The selectivity of MIP₂ for lactose in aqueous media was also evaluated in comparison with different mono‐ and disaccharides. The data showed that the affinity of MIP₂ for lactose is significantly higher than other saccharides. The imprinted hydrogel was finally used as a sorbent for separation of lactose from milk. CONCLUSIONS: The results indicated that MIP₂, as an optimised imprinted hydrogel, can effectively bind lactose and decrease its concentration in milk. Copyright © 2012 Society of Chemical Industry     

Efficacy of multipurpose solutions against Acanthamoeba species.

AIM: The disinfection efficacy of contact lens multipurpose solutions (MPSs) against Acanthamoeba polyphaga (Ros) and Acanthamoeba castellanii (ATCC30868) cysts and trophozoites was determined by both biocidal and manufacturer-recommended no-rub/rinse regimen testing. METHODS: A biocidal assay using four MPSs (ReNu with MoistureLoc, Opti-free Express, Solo-care Plus, and Complete MoisturePlus) was conducted with or without the presence of organic soil. A second test procedure compared the ability of five MPSs (ReNu with MoistureLoc MPS, ReNu MultiPlus, Opti-free Express, Solo-care Aqua, and Complete MoisturePlus) to remove and kill Acanthamoeba species cysts and trophozoites from SofLens 38 and Surevue conventional hydrogel lenses, and Focus Night & Day silicone hydrogel lenses using the manufacturer-recommended regimen. RESULTS: In the biocidal assay, only ReNu with MoistureLoc successfully killed both trophozoites and cysts (>3 log) within the manufacturer-recommended soak time. A >3 log decrease in trophozoites, but not cysts, was reported for Opti-free Express; however, Solo-care Plus and Complete MoisturePlus did not reduce the number of cysts or trophozoites by >3 log during the manufacturer-recommended soak time. In the no-rub/rinse regimen tests, only ReNu with MoistureLoc removed an inoculum of 2 x 10(5) trophozoites or cysts from SofLens 38 and Surevue hydrogel lenses, as well as Focus Night & Day silicone hydrogel lenses. Less than 10 viable organisms were recovered from the lenses after the 10s rinse and 4h soak. Opti-free Express, Solo-care Aqua, and ReNu MultiPlus were effective at removing trophozoites and cysts from SofLens 38 and Surevue conventional hydrogel lenses, but not from Focus Night & Day silicone hydrogel lenses. In excess of 10 viable organisms were recovered from all lenses after the manufacturer-recommended regimen using Complete MoisturePlus. CONCLUSIONS: These data suggest that some MPSs, when used as recommended by the manufacturer, are more effective at killing representative strains of Acanthamoeba than others.     

Management of microbiological safety of ready-to-eat meat products by mathematical modelling: Listeria monocytogenes as an example

The recent Commission Regulation (EC) No 2073/2005 establishes microbiological criteria in foods. For the pathogen Listeria monocytogenes in the category ready-to-eat foods able to support its growth, other than those intended for infants and for special medical purposes, two different microbiological criteria are proposed: (i) L. monocytogenes levels should be <100 cfu/g throughout the shelf-life of the product, (ii) absence in 25 g of the product at the stage before the food has left the immediate control of the food business operator, who has produced it. The application of either the first or the second of these criteria depends on whether or not the manufacturer is able to demonstrate that the level of L. monocytogenes in the food product will not exceed 100 cfu/g throughout its shelf-life. This demonstration should be based on physico-chemical characteristics of the target product and consultation of scientific literature, and, when necessary, on quantitative models and/or challenge tests. Once the characteristics of the product as well as scientific literature show that the pathogen has potential to grow on a specific food commodity, it seems adequate to use quantitative models and/or perform challenge tests to study the extent to which L. monocytogenes could grow. In this study, we aim to illustrate with an example in cooked ham the application of quantitative models as a tool to manage the compliance with these criteria. Two approaches were considered: deterministic and probabilistic, in three different commercial brands (A, B, and C). The deterministic approach showed that the limit 100 cfu/g was exceeded largely at the end of the shelf-life of all three; however, when reducing the storage time, the level of L. monocytogenes remained below 100 cfu/g in B. The probabilistic approach demonstrated very low percentiles corresponding to 100 cfu/g; when reducing the storage time, percentiles for three products increased, especially in products B and C (from 4.92% to 75.90%, and from 0.90% to 73.90%, respectively). This study shows how different storage times influence the level of L. monocytogenes at the end of the shelf-life of cooked ham, and, depending on the level reached, the microbiological criterion applied should be different, as stated above. Beside this, the choice of either point-estimate or probabilistic approach should be determined by the competent sanitary authority, and, in case of selecting the second approach, a certain percentile for the level 100 cfu/g should be established.     

In vitro evaluation of the dehydration characteristics of silicone hydrogel and conventional hydrogel contact lens materials.

PURPOSE: This study investigated the in vitro dehydration performance of silicone hydrogel and conventional hydrogel contact lens materials. METHODS: In vitro dehydration was assessed using a gravimetric method. The mass loss over time of Focus Night&Day, PureVision, Optima, Acuvue and Proclear Compatibles was measured as the ambient temperature increased from room temperature to 34 degrees C under varying airflow and humidity conditions. RESULTS: Dehydration data demonstrated a typical ogival form. The results were best fitted with a double exponential, non-linear regression model, which accounted for at least 99% of the variance. Regardless of material, increased airflow had a greater impact on dehydration rate than increased humidity (P<0.05). Relative dehydration amounts were strongly correlated with initial water content (r(2)=0.92), with higher water content materials dehydrating to a greater extent. CONCLUSIONS: In vitro dehydration studies of conventional and novel silicone-containing hydrogel materials indicated that evaporation rates from materials are predominantly water content related, with only subtle differences between materials of similar water contents being seen. Environmental conditions have a significant impact on in vitro dehydration, with increased airflow having a greater impact than reduced humidity on increasing dehydration rates. In vitro dehydration is closely related to bulk water diffusion rates and, as a result of their low water content, silicone-containing hydrogel materials exhibit low levels of dehydration compared with high water content hydrogel contact lens materials. Further, in vivo studies are necessary to see if the in vitro dehydration behaviour of silicone hydrogel materials is predictive of in-eye performance.     

头孢霉AL031真菌固体发酵产物抗氧化、抑菌活性研究

基于原有固体发酵条件,以提取物清除DPPH自由基的能力为评价指标,探讨头孢霉AL031真菌固体发酵的最佳时间和次生代谢产物的提取条件。用DPPH法和光敏化合物微生物法测定其次生代谢产物的抗氧化活性,微生物纸片法测定其抑菌活性。结果表明:头孢霉AL031真菌固体发酵的最佳培养时间为9d,最佳提取条件为以乙酸乙酯浸泡,其提取物对DPPH自由基的EC50为5.84μg/mL,光敏化合物微生物法亦证明其具有良好的抗氧化活性。抑菌实验表明头孢霉AL031真菌的次生代谢产物具有广谱抑菌作用。