Challenge testing: principles and practice

It is difficult to predict accurately the ultimate effectiveness of a preservative in any but the simplest cosmetic or pharmaceutical formulation. It is thus necessary to obtain some assurance of its likely in-use performance in a formulated product. A challenge test is a procedure in which a product is challenged by exposure to specified types of bacteria and fungi to determine whether it is adequately preserved. Assessment of preservative efficacy is needed over the intended shelf-life of that product. Test organisms should be representative of those likely to occur as contaminants during use and should consist of Gram-positive and Gram-negative bacteria, mould and yeast. In-house factory isolates obtained as a result of contamination of earlier batches of a product may also be included. The organisms, as single or mixed inocula, are inoculated (usually as a single challenge, although some advocate multiple challenges) into samples of the product and aliquots removed at appropriate intervals for the determination of survivors. Interpretation of data is normally based on pharmacopoeial or other official protocols. Challenge testing should be undertaken at the beginning, during and at the end of the shelf-life of the product. An alternative, the D-value, approach is open to criticism and further studies are required that utilize rapid methods, e.g. impedance, for the detection of survivors before these can be considered to be a suitable replacement for the more traditional but very time-consuming, viable counting procedures.     

In vitro induction of apoptosis, necrosis and genotoxicity by cosmetic preservatives: application of flow cytometry as a complementary analysis by NRU

Preservatives are used in cosmetics to prevent microbial contamination; however, some preservatives are not free of allergenic and cytotoxic potential. Allergenicity and cytotoxicity potential values are major aspects of preservative safety, which determine limitations and maximum concentration dose in a cosmetic product. The purpose of this study was to investigate and compare the in vitro apoptosis, necrosis and genotoxicity-inducing potential of five different types of preservatives: Phenoxyethanol (PE), Propylparaben (PP), Methylparaben (MP), Benzyl Alcohol (BA) and Ethylhexyl Glycerine (EG). In vitro experiments were carried out on human dermal fibroblasts by a quantitative flow cytometry method, using specific cell markers (Annexin V, Propidium Iodide and H2AX). We compared the resulting cell viability by means of neutral red uptake (NRU) and established the IC(50) . Our results showed that PE, PP, MP and BA have similar cytotoxic mechanisms (high apoptosis and necrosis levels only at the test concentration of 1%), whereas EG showed only an apoptosis pathway. For genotoxicity, both parabens yielded the highest values. Results obtained by flow cytometry for necrosis were comparable to those produced by NRU; however, NRU does not distinguish apoptosis from necrosis. We propose that flow cytometry is a more sophisticated methodology for understanding the cytotoxic mechanisms of cosmetic preservatives and can be used to complement the NRU.     

Electroanalytical determination of the sunscreen agent octocrylene in cosmetic products

An electroanalytical method was developed to detect and quantify the sunscreen agent octocrylene (OCR) in cosmetic products. The method was based on electrochemical reduction, using voltammetric techniques. OCR was reduced at -0.97 V vs. Ag/AgCl on a glassy carbon electrode using a mixture of Britton-Robinson buffer (0.04 mol L(-1)) and ethanol (7 : 3, v/v) as the supporting electrolyte solution. Under optimized conditions and square-wave voltammetry, OCR response was linear from 5.0 × 10(-6) to 8.0 × 10(-5) mol L(-1) (r = 0.9995), with a limit of detection of 2.8 × 10(-6) mol L(-1). The proposed electroanalytical method proved simple, fast and suitable for detection and quantification of OCR in samples of cosmetic products, with satisfactory results in the recovery test and analytical determination in real samples.     

化妆品乳液中防腐剂测定能力验证研究

目的设计组织化妆品乳液中防腐剂测定能力验证项目,了解全国化妆品检测机构防腐剂的测定能力,帮助提高实验室检测水平和质量控制能力。方法制备分割水平对样品,对各参加实验室乳液中对羟基苯甲酸甲酯和对羟基苯甲酸乙酯的测定结果进行统计分析,通过Z比分数评价实验室检测能力,并对离群数据进行技术分析。结果在P0.05的水平,样品均匀性符合要求且至少在3个月内保持稳定,满足能力验证计划要求。64个实验室参加了本次计划,满意结果数为39家,满意率为61%。结论多数参加实验室检测能力结果满意,表明化妆品中防腐剂检测水平总体良好。     

Determination of α-bisabolol and d-panthenol in cosmetic products by gas chromatography

α-bisaboloi and d -panthenol are used in many cosmetic preparations, respectively, for their anti-inflammatory and regenerating properties. Their quantitative determination was an important element of their evaluation in these emulsions. Their concentration has been determined by gas chromatographic techniques, using a flame ionization detector. In both cases, the internal standards have been chosen for their compatibility with the analysis of extracted substances.
Owing to the complexity of the cosmetic formulations, a preliminary extraction of α-bisabolol and d -panthenol was necessary. For the two substances the preparative separation was based on a liquid–liquid extraction. After dissolving the emulsion in methanol and diluting it with an aqueous buffer solution α-bisabolol was then extracted by ethyl acetate and d -panthenol by ethyl formate.     

乳酸菌细菌素应用于肉制品防腐剂的研究进展

乳酸菌现已被广泛应用于饲料、医疗、生物防治、食品和发酵工业中,其所产细菌素由于具有一定的抑菌作用且无毒副残留,因而逐渐受到人们的重视,并被利用来开发天然的生物防腐剂.概述了细菌素的分类、抑菌作用机制以及近年来国内外报道的有关乳酸菌细菌素在肉制品防腐中的作用的研究进展.     

化学法保鲜香菇的研究

本实验以新鲜香菇为原料,以其贮藏期间的感官评价、褐变率、失重率、呼吸强度以及VC的含量为指标,研究了焦磷酸钠、氯化钠和过氧化氢对其贮藏期间品质的影响。结果表明,各保鲜剂混合使用的效果优于单独使用,以3.0%H2O2+0.2g/LNaCl为最佳配比浓度。      

化学保鲜在国外鲜切果蔬上的应用进展

近年来,随着收入水平提高和生活节奏加快,鲜切果蔬为越来越多的人所接受。在介绍鲜切果蔬定义的基础上,着重介绍了鲜切果蔬化学保鲜剂包括消毒清洗剂、生理调节剂、钙类保鲜剂、抗褐变剂和抗菌剂5种保鲜剂对鲜切果蔬的影响及作用机理,同时就保鲜剂的使用方法进行了阐述。最后,对鲜切果蔬的发展前景及注意事项提出了几点看法。     

Determination of alpha-hydroxy acids in cosmetic products by high-performance liquid chromatography with a narrow-bore column

This paper reports the results of a study carried out to develop a simple, rapid and sensitive method for the separation, identification and quantitative measurement of alpha-hydroxy acids in commercial cosmetics using high-performance liquid chromatography (HPLC). This method is successfully applied to the simultaneous identification and quantitative determination of glycolic, lactic, malic, tartaric and citric acids employing a reversed phase narrow-bore column under isocratic condition and UV detection. The method is validated by determining the precision of replicate analyses and accuracy by analyzing samples with and without adding know amount of the alpha-hydroxy acids. The procedure is suitable for routine analyses of commercial cosmetics.     

Evaluation of antimicrobial effectiveness of C-8 xylitol monoester as an alternative preservative for cosmetic products

Xylitol is a natural sugar derived from plants, fruits and vegetables, whose antimicrobial properties are described in the literature. This study aimed to evaluate the antimicrobial effectiveness of C-8 xylitol monoester, for its use as a preservative in cosmetic formulations. The minimum inhibitory concentration (MIC) was determined by the broth macrodilution method, and the antimicrobial effectiveness of C-8 xylitol monoester was determined by using challenge test method. The results obtained in the determination of minimum inhibitory concentration are between 1.0% and 1.25% for Staphylococcus aureus, Escherichia coli and Candida albicans and between 1.0% and 1.5% for Pseudomonas aeruginosa and Aspergillus niger. The amount of 1% of C-8 xylitol monoester was added to the lotion used in the challenge test, observing a rapid decline in the number of CFU g(-1) in stages of evaluation after contamination of the product by all bacteria. The same occurs in relation to C. albicans, which shows a 90% reduction in the number of CFU g(-1). Regarding A. niger, similar reduction is observed when pH value of the lotion is adjusted from 5.5 to 7.0. The results indicate that under the tests conditions, C-8 xylitol monoester has antimicrobial activity and could be considered as an alternative preservative for cosmetic formulations.     

四种肉类保鲜新技术的研究现状与展望

肉类作为机体摄取蛋白质的主要来源之一,其安全性和新鲜性一直深受食品生产者和广大消费者的密切关注。传统的保鲜技术在延长肉类保质期方面存在一定的局限性,单靠传统技术已经难以满足消费者获得高品质新鲜肉品的要求,因此亟待提出新型的保鲜技术进一步改进传统的保鲜技术。本文从保鲜机制、保鲜应用、研究现状与展望等方面出发,对国内应用较少的冰温保鲜、活性包装保鲜、超高压保鲜、生物保鲜剂保鲜等四种保鲜技术进行了阐述,期望为进一步研究新型保鲜剂技术和扩大它们在食品工业中的应用提供重要的理论基础。     

神经酰胺对皮肤生理作用及其在化妆品中应用

神经酰胺在皮肤角质层中主要作用包括：保湿作用、屏障作用、抗衰老作用和美白作用,这些作用使其成为化妆品重要生物添加剂。该文介绍神经酰胺在化妆品中应用进展,并展望其在化妆品中发展前景。     

生物保鲜剂在果蔬保鲜中的应用研究进展

生物保鲜剂具有天然、无毒等特点,越来越受到人们的青睐,在果蔬保鲜中有着广阔应用前景。本研究概述了生物保鲜剂的定义与保鲜机理,然后从植物类、动物类、微生物类和酶类这4个方面详细阐述生物保鲜剂用于果蔬保鲜的国内外研究现状,分析了生物保鲜剂在果蔬保鲜发展中存在的问题,并对其应用前景进行展望,旨在为生物保鲜剂在果蔬保鲜应用的深入研究提供参考。     

溶菌酶、Nisin、壳聚糖复合保鲜剂对冰鲜银鲳保鲜效果的研究

在单一生物保鲜剂实验研究的基础上,通过三因素三水平的L9（33）正交实验,将溶菌酶、壳聚糖和Nisin进行复配,以细菌总数和挥发性盐基氮（TVB-N）作为评价指标,评定冰鲜鲳鱼的品质变化,以确定保鲜效果最佳的复合型生物保鲜剂。结果表明:溶菌酶0.4g/L、壳聚糖5g/L、Nisin 0.4g/L为复合保鲜剂的最佳配比。经过最佳配比复合保鲜剂浸泡的银鲳鱼,其感官评分、细菌总数、TVB-N、硫代巴比总酸（TBA）值均优于对照组,在冷藏条件下能使银鲳的一级长2³d,二级鲜度延长6⁷d。      

Anti-irritant potential of cosmetic raw materials and formulations

The investigation studied the anti-irritant potential of several substances commonly employed in cosmetic formulations as basic components of the emulsion or as active ingredients, and evaluated the effect of the emulsifier. Five different emulsions were made irritating by addition of croton oil, in sufficient quantity to provoke a clearly adverse reaction in the rabbit, i.e. primary cutaneous irritation index (PII) close to 2. The PII was determined according to the official French methods by applying to symmetrical areas of the back, the irritant base as control and the same base containing the test substance. Fifty-five ingredients were evaluated: gelling agents, plant extracts, molecules defined as healing, anti-inflammatory substances or anaesthesic compounds, etc. The test substances were added to the emulsion at concentrations close to the ones generally found in cosmetics. The qualitative and the quantitative composition of the oil phase was similar for each emulsion.
Several gelling agents, thickeners and polymers which notably reduce skin contact with an irritant, gave good results. Some of the usual healing, anti-inflammatory, local anaesthesic compounds gave the expected results. Some ingredients, though well known, were ineffective. The type of emulsifier, by modifying cutaneous penetration and bio-availability of the active ingredients, may play an important role.
Le potential anti-irritant de constituants de base et compositions cosmétiques     

Eco-friendly methodologies for the synthesis of some aromatic esters, well-known cosmetic ingredients

Solid-liquid solvent-free phase transfer catalysis (PTC) and acidic catalysis in dry media were applied, with noticeable improvement and simplification over classical procedures in a Green Chemistry context, to the synthesis of some aromatic esters useful as cosmetic ingredients: 3-methylbutyl 4-methoxycinnamate, 2-ethylhexyl 4-methoxycinnamate, 2-ethylhexyl 4-(dimethylamino)benzoate and 2-ethylhexyl salicylate, well-known ultraviolet B sunscreen filters; 4-isopropylbenzyl salicylate, UV absorber and cutaneous antilipoperoxidant; propyl 4-hydroxybenzoate and butyl 4-hydroxybenzoate (parabens), antimicrobial agents. The reactions were performed under microwave (MW) activation and conventional heating. The best results for the synthesis of cinnamic, salicylic and 4-(dimethylamino)benzoic esters were achieved by in situ preformed carboxylates alkylation with alkyl bromides using PTC. The 4-hydroxybenzoates were obtained in good yields by classical esterification of the acid with alcohols using a simple heterogeneous mixture of reagents with catalytic amounts of p-toluenesulfonic acid (PTSA). The comparisons of yields and thermal profiles under either MW or conventional heating were studied and reported.     

二氧化氯对猪肉、毛肚和鸭肠保鲜效果的影响

以猪肉、毛肚和鸭肠为原料,将其放置于浓度为50、150、250mg/L的二氧化氯溶液中浸泡1～2min,用NY/T632-2002冷却肉标准评价保藏效果。结果表明,用50mg/L的二氧化氯处理猪肉,在冷藏条件下能有效地延长其货架期到6d;用150mg/L二氧化氯处理毛肚,可以有效地延长毛肚的保藏期到10d;用150mg/L的二氧化氯处理鸭肠可将其保质期有效地延长到9d。一定浓度的二氧化氯可以有效地延长猪肉、毛肚和鸭肠的保藏期。     

Novel natural food preservatives and applications in seafood preservation: a review

Food preservative additives are natural or synthetic substances which delay degradation in foods caused by microbial growth, enzyme activity, and oxidation. Until recently, the use of synthetic additives in food was more common. However, synthetic additives have not been widely accepted by consumers in recent years due to their assumed adverse effects on their health. Therefore, the tendency of consumers to natural additives is increasing day-by-day. Seafood is an easily perishable food due to its chemical composition. Immediately after harvest, changes in odor, taste, and texture in fishery products can be noticed. For this reason, measures to protect the product must be taken immediately after harvest or catching. Various preservation methods have been developed. In addition to various technological methods, preservative additives are used in fresh or processed seafood as well as in other foods. This review focuses on novel natural preservatives from different sources such as plants, bacteria, fungi, animals and algae, and their use in seafood to protect quality and prolong shelf life. © 2018 Society of Chemical Industry     

低温肉制品中微生物检测及优势菌群的鉴定和分析

对市售某3个品牌的在架真空包装冷藏肉制品样品,进行嗜冷菌和中温菌微生物检测,利用16SrDNA序列分析鉴定其中优势菌群.结果表明:10-3稀释度检测的菌落总数总是高于10-1和10-2稀释度的菌落总数.说明肉制品中防腐剂的浓度在低稀释度下仍然能抑制微生物生长,干扰细菌总数的测定,造成误判.样品中优势菌属主要有3类:芽孢杆菌属Bacillus、假单胞菌属Pseudomonas、葡萄球菌属Staphylococcus.条件致病菌蜡样芽孢杆菌和葡萄球菌在3个品牌产品中均有较高检出率(13.3％～24.4％),而且均能在10℃和30℃生长,具有潜在致病性.