Growth and mycotoxin production by fungi in atmospheres containing 80% carbon dioxide and 20% oxygen

The effect of atmosphere containing 80% CO₂ and 20% O₂ on growth of Mucor plumbeus, Fusarium oxysporum, Byssochlamys fulva, Byssochlamys nivea, Penicillium commune, Penicillium roqueforti, Aspergillus flavus, Eurotium chevalieri and Xeromyces bisporus was investigated. Production of aflatoxin by A. flavus, patulin by B. nivea, roquefortine C by P. roqueforti, and cyclopiazonic acid by P. commune was also studied. Fungal growth was evaluated by three methods: colony diameter, hyphal length or mycelium dry weight and ergosterol content. Among the nine fungal species examined, two E. chevalieri and X. bisporus, did not grow under these conditions. In this study, fungi differed in their response to modified atmospheres in biomass, ergosterol content, mycotoxin production and morphology. Reductions of 57.8-96.9%, 73.7-99.6% and 91.5-99.9% were obtained in colony diameter, hyphal length and ergosterol content, respectively, under this atmosphere compared to air. Ergosterol content was more affected in most species than other measurements. Patulin, cyclopiazonic acid and roquefortine C were produced in this atmosphere, although levels were very low and aflatoxin was not produced at all. Growth was quite extensive as measured by colony diameters, but hyphal lengths were low and ergosterol production was also affected in all species of this study.     

生物标记法剖析传统酿造用大曲微生物群落结构

建立一种基于生物标记物表征大曲类固态发酵体系微生物群落结构的生物化学方法。以微生物细胞膜的特征组分磷脂脂肪酸(PLFAs)组成信息为指标,描述大曲微生物群落结构特征;采用麦角甾醇标记物含量估算出样品真菌生物量。结果显示：5种不同生产工艺的大曲样品中共计检出18种磷脂脂肪酸,优势PLFAs是16:0、18:2ω6,9和18:1ω9,占总PLFAs物质的量的90%以上。从PLFAs组成特征判断5类大曲中优势菌群均为真菌。基于麦角甾醇含量与真菌生物量的关联性,估算出绝干大曲中的真菌生物量分布在(110.45±4.60)～(218.47±11.19)μg/mg。     

Fitting of colony diameter and ergosterol as indicators of food borne mould growth to known growth models in solid medium

Growth of a range of 14 common food spoilage fungal species was evaluated along time as a function of both colony diameter and ergosterol content on malt extract agar. Growth was assessed under different environmental conditions following a central composite design. The suitability of using either linear, Gompertz's or Baranyi's models for primary modelling of the results was tested. Regarding colony diameters, using either linear or asymptotic Baranyi's function gave better estimations of growth rate and lag phase when no asymptotic trend was observed. When a decrease in growth rate was observed with time, standard Baranyi's model was chosen, although the search for new mechanistic models specific for moulds would probably improve the estimations. The use of Gompertz equation led, in general, to overestimated parameters. Ergosterol showed good performance as a fungal growth indicator for the whole range of species. Finally, significant correlation coefficients were found between ergosterol and colony diameters, suggesting that both parameters may be useful for primary modelling and thus for subsequent secondary modelling.     

Comparison of the compact dry TC and 3M petrifilm ACP dry sheet media methods with the spiral plate method for the examination of randomly selected foods for obtaining aerobic colony counts

Two hundred thirty-six randomly selected food and milk samples were examined to obtain aerobic colony counts by two dry sheet media methods and a standard Public Health Laboratory Service spiral plate method. Results for 40 samples were outside the limits of detection for one or more of the tested methods and were not considered. (The limits of detection for the spiral plate method were 200 to 1 x 10(8) CFU/ml for the spiral plate method and 100 to 3 x 10(6) CFU/ml for the dry sheet media methods.) The remaining 196 sets of results were analyzed further. When the results from the three methods were compared, correlation coefficients were all >0.80 and slopes and intercepts were close to 1.0 and 0.0, respectively. Mean log values and standard deviations were very similar for all three methods. The results were evaluated according to published UK guidelines for ready-to-eat foods sampled at the point of sale, which include a quality acceptability assessment that is based on aerobic colony counts. Eighty-six percent of the comparable results gave the same verdict with regard to acceptability according to the aerobic colony count guidelines. Both dry sheet media methods were comparable to the spiral plate method and can be recommended for the examination of food.     

藏灵菇发酵奶发酵特性的研究

本文研究了藏灵菇发酵奶发酵过程中酸度、有机酸、挥发性风味物质及微生物数量的变化,在发酵0、4、8、12、16、20h时采样,用高效液相色谱(HPLC)跟踪发酵过程中乳酸、乙酸和柠檬酸的变化;用气相色谱(GC)跟踪了发酵过程中乙醇、丁二酮、乙醛和丙酮的变化。实验结果表明,乳酸和乙酸在发酵过程中都呈上升趋势,发酵4h时,乳酸的生成量约是乙酸的20倍,发酵结束乳酸的量为8.56g/L(TK1),7.73g/L(TK2);乙酸的量为0.71g/L(TK1),0.81g/L(TK2),乳酸的量约是乙酸的9～12倍。柠檬酸从发酵开始就呈下降趋势。挥发性风味物质中乙醇的生成量最大,发酵结束分别达到3134mg/L(TK1),4994mg/L(TK2);丁二酮和乙醛的量较普通酸奶高,分别达到62.4mg/L(TK1)和37.8mg/L(TK1)。本研究也对发酵过程中微生物进行了分析,发酵结束,发酵奶中乳杆菌达到2.3×109CFU/ml(TK1),1.3×108CFU/ml(TK2);乳球菌达到1.3×109CFU/ml(TK1),1.1×108CFU/ml(TK2);酵母菌1.6×106CFU/ml(TK1),6.6×106CFU/ml(TK2)。TK1和TK2之间存在较大差异,TK1的风味好于TK2。     

Some probiotic properties of yeast isolates from infant faeces and Feta cheese

The use of modified atmospheres to prevent fungal growth and mycotoxin production in cheese was evaluated. Eight fungal species: Mucor plumbeus, Fusarium oxysporum, Byssochlamys fulva, B. nivea, Penicillium commune, P. roqueforti, Aspergillus flatus and Eurotium chevalieri were inoculated onto cheese and incubated under conditions of decreasing concentrations of O2 (5% to < 0.5%) and increasing concentrations of CO2 (20-40%). Fungal growth was measured by colony diameter and ergosterol content. All fungi examined grew in atmospheres containing 20% and 40% CO2 with 1% or 5% O2, but growth was reduced by 20-80%, depending on species, compared with growth in air. The formation of aflatoxins B1 and B2, roquerfortine C and cyclopiazonic acid was greatly decreased but not totally inhibited in these atmospheres. At 20% or 40% CO2 with < 0.5% O2, only B. nivea exhibited growth, which was very slow. Growth of F. oxysporum, B. fulca, P. commune and A. flavus showed good correlations between colony diameter and ergosterol content. However, for the other species correlations were inconsistent.     

解冻猪肉中优势腐败菌致腐能力研究

将解冻猪肉中的优势腐败菌(假单胞菌属、热死环丝菌和肠杆菌科)接种到灭菌肉上研究其在不同温度贮藏过程中腐败的特点。在贮藏期间每天进行感官评价,测定各腐败菌的菌落数(CFU)、挥发性盐基氮(TVB-N)、脂肪氧化值,并以产生腐臭味时的TVB-N产量因子Y(TVB-N/CFU)作为各优势腐败菌腐败能力的定量指标。研究结果表明：至贮藏期第5天时解冻猪肉已产生强烈的腐臭味,热死环丝菌菌数在4、0℃和－5℃贮藏时分别达11.28lg(CFU/g)、9.63lg(CFU/g)和6.62lg(CFU/g),而相应的TVB-N值分别达14.92、14.50mg/100g和9.10mg/100g;与之类似,假单胞菌属菌数4、0℃和－5℃贮藏时分别达9.46lg(CFU/g)、8.87lg(CFU/g)和5.37lg(CFU/g),TVB-N值分别达21.59、14.49mg/100g和8.97mg/100g。研究表明热死环丝菌和假单胞菌属导致解冻猪肉腐败能力较强。     

Bacteriological quality of aquacultured freshwater fish portions in prepackaged trays stored at 3 degrees C

Fresh trout fillets and salmon slices packed in trays were obtained from two multinational chain supermarkets and evaluated for freshness and bacteriological quality immediately after packaging and during storage at 3 degrees C. Initial aerobic counts at 30 and 25 degrees C were significantly (P < 0.05) lower in trout fillets (5.27 +/- 0.57 and 4.87 +/- 0.80 log CFU/g, respectively) than in salmon slices, where levels in excess of 6 log CFU/g were found. In both products, initial Enterobacteriaceae counts were slightly higher than 3 log CFU/g and increased significantly during shelf life by approximately 3 log CFU/g. Most of the enterobacteria were identified as Citrobacter freundii, Hafnia alvei, and Enterobacter cloacae. On day 0, most probable number (MPN) counts of total and fecal coliforms were not significantly different, numbers of the latter group being approximately 4 MPN/g. Escherichia coli was only detected when fish was spoiled. Although initial presumptive Staphylococcus aureus counts were approximately 3 log CFU/g, only 4 of 84 selected colonies belonged to this species. Neither Salmonella nor antimicrobial residues were detected in any sample. Ethanol content in salmon slices did not significantly (P > 0.05) increase until they became inedible. Significant correlation (r = +0.72, P < 0.05) was observed between this chemical index and viable counts at 30 degrees C only when salmon slices were inedible. Trout fillets were acceptable for 7 days, and salmon slices showed signs of spoilage after 4 days. Although public health concerns associated with packed trout and salmon appear to be minimal, data on sensory quality, shelf life, and total viable and Enterobacteriaceae counts strongly suggest the need to improve the quality control systems used by European multinational retailers, especially for imported salmon.     

Hygiene indicator microorganisms for selected pathogens on beef, pork, and poultry meats in Belgium

Several bacterial indicators are used to evaluate hygiene during the meat slaughtering process. The objectives of this study were to assess the Belgian baseline data on hygienic indicators and the relationship between the indicators and zoonotic agents to establish hygiene indicator criteria for cattle, pig, and chicken carcasses and meat. The study used the results from the official Belgian surveillance plan from 2000 to 2003, which included the monitoring of Escherichia coli counts (ECC), Enterobacteriaceae counts (EC), aerobic colony counts (ACC), and Pseudomonas counts (PC). The sampling method was the wet and dry swabbing technique for cattle and pig carcasses and neck skin excision for broiler and layer chicken carcasses. The 75th and 95th percentiles of ECC were -0.20 and 0.95 log CFU/cm2 for cattle carcasses, 1.20 and 2.32 log CFU/cm2 for pig carcasses, and 4.05 and 5.24 log CFU/g for chicken carcasses. The ACC were 2.1- to 4.5-log higher than the ECC for cattle, pigs, and chickens. For cattle and pig carcasses, a significant correlation between ECC, EC, and ACC was found. ECC for pork and beef samples and EC in pig carcasses were significantly higher in samples contaminated with Salmonella. In poultry samples, ECC were in general higher for samples containing Salmonella or Campylobacter. Thus, E. coli may be considered as a good indicator for enteric zoonotic agents such as Salmonella for beef, pork, and poultry samples and for Campylobacter in poultry samples.     

冷藏鲤鱼和罗非鱼优势腐败菌腐败能力分析

通过分析接种腐败菌的鲤鱼和罗非鱼无菌鱼块贮藏中感官、腐败代谢产物和腐败菌的变化,以腐败菌的生长动力学参数和腐败代谢产物的产量因子(YTVBN/CFU)为指标,探讨冷藏鲤鱼和罗非鱼优势腐败菌假单胞菌和腐败希瓦氏菌的腐败能力。结果表明:接种腐败希瓦氏菌和恶臭假单胞菌的鲤鱼无菌鱼块的货架期分别为132h和162h,此时的TVBN值为27.12mg/100g和22.51mg/100g,腐败希瓦氏菌和恶臭假单胞菌菌数为8.96 lg(CFU/g)和9.07 lg(CFU/g),产量因子YTVBN/CFU为9.28×10-9mg TVBN/CFU和1.81×10-8mg TVBN/CFU。接种荧光假单胞菌和腐败希瓦氏菌的罗非鱼无菌鱼块的货架期分别为132h和144h,此时的TVBN值为23.46mg/100g和24.30mg/100g,荧光假单胞菌和腐败希瓦氏菌菌数为8.83 lg(CFU/g)和9.12 lg(CFU/g),产量因子YTVBN/CFU为1.67×10-8mg TVBN/CFU和9.10×10-9mg TVBN/CFU。结合两种养殖鱼冷藏过程中的菌相变化和腐败菌在腐败过程中的作用,初步得出冷藏罗非鱼和鲤鱼的特定腐败菌是假单胞菌,两种腐败菌都具有较强的腐败能力。     

Phytochemical Content,Antioxidant Properties,and Phenolic Profile of Tunisian Raisin Varieties (Vitis Vinifera L.)

Four raisin (Vitis vinifera L.) varieties, Chriha, Razeki, Assli, and Meski, were evaluated for total phenolic content, total o-diphenol content, total flavonoid content, total condensed tannin, total carotenoid content, and total anthocyanin content. Antioxidant potential was assessed by three assays: 2,2-Diphenyl-1-Picrylhydrazyl and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical scavenging capacity and ferric reducing power. Individual phenolic profiles were determined by high-performance liquid chromatography. The results revealed that the four raisin varieties had considerable phenolic content and antioxidant activity. Chriha had the highest total phenolic content (534.2 mg/g dry weight) while Meski had high total condensed tannin (208.6 mg CEQ/g dry weight), TAC (137 mg/100 g dry weight), total o-diphenol content (115.8 mg/g dry weight), total flavonoid content (93 mg CEQ/g dry weight), and total carotenoid content (33 mg/100 g dry weight). There were significant differences in phenolic content among the four varieties (p < 0.05). Meski had the highest 2,2-Diphenyl-1-Picrylhydrazyl scavenging capacity, while Chriha had adequate reducing power and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid scavenging capacity. The individual phenolic compounds (2.96–6.54 mg/g dry weight) were variety-dependent.     

Toxigenic potential of Fusarium culmorum strains isolated from French wheat

Sixty F. culmorum strains were isolated from wheat grains collected from different wheat-growing areas in France and from different cultivars. The isolates were grown on autoclaved wheat grain to assess their ability to produce trichothecenes and zearalenone. Fungal biomass was evaluated through the ergosterol grain content. All the isolates produced zearalenone (0.39-1660mg kg -1 ). Thirty-five of the 60 F. culmorum produced nivalenol (0.11-11.7mg kg -1 ), 12 of 60 produced fusarenone X (0.05-8.42mg kg -1 ), five of 60 produced 15-acetyldeoxynivalenol (0.48- 27.7mg kg -1 ), 13 of 60 produced 3-acetyldeoxyni-valenol (0.07-21.0mg kg -1 ) and 24 of 60 produced deoxynivalenol (0.92-51.9mg kg -1 ). According to the results, the distribution of the different chemotypes as well as the high and the low mycotoxin-producing Fusarium strains could not be associated to geographical origin.     

Real-time viable-cell mass monitoring in high-cell-density fed-batch glutathione fermentation by Saccharomyces cerevisiae T65 in industrial complex medium

An on-line monitoring of viable-cell mass in high-cell-density fed-batch cultivations of Saccharomyces cerevisiae grown on an industrial complex medium was performed with an in situ capacitance probe fitted to a 50-l fermentor. Conventional off-line biomass determinations of several parameters, including dry cell weight (DCW), optical density at 600 nm wavelength (OD(600)), packed mycelial volume (PMV) and number of colony forming units (CFU), were performed throughout the bioprocess and then compared with on-line viable-cell concentrations measured using a capacitance probe. Capacitance versus viable biomass and all off-line biomass assay values were compared during glutathione fermentation in industrial complex culture media. As a result, the relationship between the number of colony forming units and capacitance with a correlation coefficient (R) of 0.995 was achieved. Simultaneously, compared with those determined by at-line indirect estimation methods including oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER), the specific growth rates estimated by on-line capacitance measurement could be more reliable during glutathione fermentation. Therefore, it is concluded that a capacitance probe is a practical tool for real-time viable biomass monitoring in high-cell-density fed-batch cultivation in a complex medium.     

重组巴斯德毕赤酵母工程菌发酵生产藻蓝蛋白的研究

探讨重组巴斯德毕赤酵母工程菌发酵生产藻蓝蛋白的特性,以期能够通过基因工程和发酵工程技术大规模的生产活性重组藻蓝蛋白。先用甘油作碳源培养重组巴斯德毕赤酵母工程菌,达到一定生物量后,再用甲醇诱导外源重组藻蓝蛋白基因的表达,并测定了甘油浓度、细胞干重、细胞光密度和藻蓝蛋白含量的变化。结果表明:所获得的细胞干重最高达41.93g/L,细胞光密度最高为182.77,藻蓝蛋白的最高产量为61.20mg/L,分泌到胞外的藻蓝蛋白的最高产量为24.32mg/L。该研究为实现藻蓝蛋白的产业化生产奠定了良好的基础。     

Bactometer system versus traditional methods for monitoring bacteria populations in salchichón during its ripening process

The performance of the Bactometer system (an impedimetric microbial monitoring system) compared with traditional methods (microbial colony counts) for monitoring bacterial populations (lactic acid bacteria [LAB], Enterobacteriaceae, and coliforms) was studied in 90 samples of an experimental salchichón (a type of Spanish ripened dry sausage) during its ripening process. The population quantitations were carried out with fresh sausage, semiripened sausage (14 days of ripening), and finished product (28 days of ripening). The results showed a high correlation between the traditional microbial colony count (in CFU per gram) and the impedance detection time: -0.98, -0.97, and -0.94 for coliforms, Enterobacteriaceae, and LAB, respectively (P < 0.01). Considering the results obtained with regard to the enumeration of populations of Enterobacteriaceae, coliforms, and LAB in salchichón during its ripening process, the advantages of impedance with respect to plate counts for monitoring the microbial dynamics of ripening processes are notable, especially in its time-saving aspects: between 19 and 21 h in the case of Enterobacteriaceae, between 7 and 20 h for coliforms, and between 32 and 46 h for LAB.     

Post-harvest storage of corn: effect of beginning moisture content on mycoflora and fumonisin contamination.

The effect of storage on mycoflora profile was monitored bimonthly in 36 corn (Zea mays L.) samples, dividing the same sample into groups dried to 11 and 14% moisture content (1008 analysis). These groups were further subdivided based on the initial total count (moulds and yeasts) up to 10(4) CFU g(-1) (12 samples, range 1.6 x 10(4) to 9.0 x 10(4), mean 3.8 x 10(4) CFU g(-1)) and up to 10(5) CFU g(-1) (24 samples, range 1.0 x 10(5) to 5.0 x 10(5), mean 2.7 x 10(5) CFU g(-1)). In the corn group dried to 11%, the fumonisin content was analysed at the initial stage (freshly harvested) and at the end of 12-month storage. Fusarium spp. and Penicillium spp. prevailed at the freshly harvested stage (100%), maintaining this profile throughout 12 months, in corn dried to both 11 and 14%. Cladosporium spp., Aspergillus spp. and Phoma spp. were also detected at lower frequencies during the storage. Fusarium spp. and the total fungal colony count during 12-month storage carried out with samples dried to 11 or 14% moisture content were statistically evaluated using ANOVA for randomized complete block design. The correlation between storage time and Fusarium spp. and total fungal colony count data was analysed by Pearson's correlation test. There was no difference in Fusarium spp. and total counts in the 10(4) CFU g(-1) initial total count group throughout the storage time (p < 0.05). There was a negative correlation between fungal population and storage time (p < 0.05) in the 10(5) CFU g(-1) initial total count group. Fumonisins were detected in all freshly harvested corn, at a mean concentration of 9.9 +/- 6.0 micro g g(-1) (range 0.74-22.6 micro g g(-)1). These values did not change in the 12-month stored corn (mean of 9.9 +/- 5.8 micro g g(-1), range 0.81-23.7 micro g g(-1)). These post harvest data indicated the importance of moisture content at the crop harvesting/predrying stage to control fungal growth and further fumonisin production.     

Volatiles for mycological quality grading of barley grains: determinations using gas chromatography-mass spectrometry and electronic nose

The possibility of using an electronic nose or gas chromatography combined with mass spectrometry (GC-MS) to quantify ergosterol and colony forming units (CFU) of naturally contaminated barley samples was investigated. Each sample was split into three parts for (i) ergosterol and CFU analysis, (ii) measurements with the electronic nose and (iii) identification of volatiles collected on an adsorbent with a GC-MS system. Forty samples were selected after sensory analysis to obtain 10 samples with normal odour and 30 with some degree of off-odour. The data set of volatile compounds and the data collected from the electronic nose were evaluated by multivariate analyse techniques. SIMCA classification (soft independent modelling of class analogy) was used for objective evaluation of the usefulness of the data from the GC-MS or electronic nose measurements for classification of grain samples as normal or with off-odour. The main volatile compounds of grain with normal odour were 2-hexenal, benzaldehyde and nonanal, while 3-octanone, methylheptanone and trimethylbenzene were the main volatile compounds of grain with off-odours. Using data from the electronic nose three samples of 40 were misclassified, while data analysis of the volatile compounds detected with the GC-MS, led to six misclassified samples. Regression models (partial least-squares, PLS) were built to predict ergosterol- and CFU-levels with data from the GC-MS or electronic nose measurements. PLS models based on both GC-MS and electronic nose data could be used to predict the ergosterol levels with high accuracy and with low root mean square error of prediction (RMSEP). CFU values from naturally infected grain could not be predicted with the same degree of confidence.     

Growth of lactic acid bacteria and Rhizopus oligosporus during barley tempeh fermentation

The zygomycete Rhizopus oligosporus is traditionally used to ferment soybean tempeh, but it is also possible to ferment other legumes and cereals to tempeh. The traditional soybean tempeh harbours a multitude of microorganisms with potentially beneficial or detrimental effects on quality. Lactic acid bacteria (LAB) have positive effects on the safety of soybean tempeh, but the effects of LAB on R. oligosporus growth have not been investigated. We have developed a cereal grain tempeh by fermenting pearled barley with R. oligosporus ATCC 64063. Four LAB species, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus reuteri and Lactococcus lactis were assessed for their growth abilities and their effects on R. oligosporus growth during barley tempeh fermentation. Growth of LAB was assayed as colony forming units (cfu), while growth of R. oligosporus was measured as ergosterol content and hyphal length. The two fungal measurements highly correlated (r=0.83, P<0.001, n=90). The ergosterol content of fungal mycelia ranged from 11.7 to 30.1 mg/g fungal dry matter. L. plantarum multiplied from 4.8 to 7.4 log cfu/g dry tempeh and L. fermentum increased from 4.4 to 6.8 log cfu/g during 24 h incubation at 35 degrees C. L. reuteri and L. lactis had significantly slower growth, with increases from 4.8 to 5.6 log cfu/g and 5.0 to 5.4 log cfu/g, respectively. The growth of R. oligosporus and the final pH (4.9) in barley tempeh were not significantly influenced by any of the LAB investigated.     

Comparison of effects of Wasabia japonica and allyl isothiocyanate on the growth of four strains of Vibrio parahaemolyticus in lean and fatty tuna meat suspensions.

Lean tuna meat suspensions (LEAN), with a fat content of 0.006%, and fatty tuna meat suspension (FATTY), with a fat content of 3.0% were inoculated with four strains of Vibrio parahaemolyticus and wasabi (Wasabia japonica Matsumura) or allyl isothiocyanate (AIT) was added before incubation at 37 degrees C. During the incubation, viable Vibrio counts were determined on TCBS agar plates. Both LEAN and FATTY suspensions were inoculated with V. parahaemolyticus AOTO-81, (1.28+/-0.20) x 10(2) CFU/ml, followed by addition of 20 mg wasabi/ml, and incubation for 8 h. The viable Vibrio counts were (7.76+/-5.93) x 10(5) CFU/ml in LEAN and (3.50+/-2.65) x 10(1) CFU/ml in FATTY. When the same strain, at (1.18+/-0.22) x 10(2) CFU/ml, was incubated for 8 h with 50.9 microg AIT/ml, viable Vibrio counts were (4.79+/-1.78) x 10(4) CFU/ml in LEAN and (1.80+/-1.30) x 10(1) CFU/ml in FATTY. Growth of the other three strains with wasabi or AIT was shown to be less in FATTY than in LEAN. These results indicate that growth of V. parahaemolyticus is inhibited more in FATTY than in LEAN by wasabi and allyl isothiocyanate.     

红曲霉固态发酵中生物量的测定方法

探讨了红曲霉固态发酵中生物量的测定方法。红曲霉固态发酵的生物量基本可以通过测定红曲霉菌体细胞中的麦角固醇和氨基葡糖含量来推断 ,对于本文中红曲霉固态发酵采用氨基葡糖法相对较好 ,可以估测出固态发酵物中的菌体量。底物干重减重与菌体量存在一定的正向关系 ,通过测定底物减重可以推断出红曲霉生长代谢状况 ,并且方法简便易行 ,易于实现在线监测