bluuebunny/crossref_metadata_2025 huggingface dataset:
THE USE OF CO2 IN PACKAGING OF FRESH RED MEATS AND ITS EFFECT ON CHEMICAL QUALITY CHANGES IN THE MEAT: A REVIEW
Authors: JAKOBSEN M. , BERTELSEN G.
Published: May 2007

The antimicrobial effect of carbon dioxide (CO2) is well documented but comparison of the large number of often contradictory studies investigating the effect of CO2 on chemical quality changes is lacking. The amount of absorbed CO2 varies from 0 ‐ 1.79 L CO2/kg meat depending on the applied packaging and storage conditions, which clearly demonstrates the necessity of optimizing these conditions with respect to the required amount of CO2. Absorption of large amounts of CO2 in meat tissue can cause a minor decrease in pH due to the dissociation of the produced carbonic acid to bicarbonate and hydrogen ions. A decrease in pH might affect other chemical quality parameters but this is not observed to be the case in the reviewed studies and general detrimental effects of CO2 cannot be found for color, weight loss or lipid oxidation. However, elevated CO2 levels can cause pore formation in cooked meat.
THE USE OF FAT REPLACERS IN FAT‐FREE SUMMER SAUSAGE1
Authors: VICKERY A.P. , ROGERS R.W.
Published: May 2007

Fat replacers were studied in summer sausage while the processing method and seasoning blend were held invariable. The substances evaluated were rice granules, potato flour/beet fiber, rice flour, and modified starch. The products were stored at 3C and analyzed for color, sensory attributes, TBARS values and proximate content at days 1, 30, and 60. The fat‐free summer sausage products were not different (P>0.05) from the control product in processing yield, pH, TBARS values, consumer acceptance, purchase intent and preference test, and sensory attributes of flavor at days 30 and 60, and overall rating at day 60. There were differences (P<0.05) between the fat‐free and control products for cooking yield, final yield, cooler shrink, chemical composition, and Hunter Color “L” and “a” values. Storage time did not affect (P>0.05) Hunter Color “a” values, tenderness, juiciness, and percent protein, yet increased (P<0.05) tartness of all summer sausage products.
CORRELATIONS BETWEEN SERUM CONCENTRATIONS OF LEPTIN AND BEEF CARCASS COMPOSITION AND QUALITY
Authors: McFADIN E.L. , KEISLER D.H. , SCHMIDT T.B. , LORENZEN C.L. , BERG E.P.
Published: May 2007

Steers (n = 84) of various genotypes raised under diverse management conditions from the 2001 Missouri State Beef carcass contest were used to evaluate the relationship between serum concentrations of leptin and beef carcass composition and quality. Serum and carcass data including hot carcass weight; adjusted 12th rib fat thickness; percentage kidney; pelvic and heart fat (KPH); marbling score; and USDA yield grades were measured at harvest. Leptin was correlated with back fat thickness over the 12th rib, yield grade, and marbling score (r = 0.35, r = 0.19, r = 0.26, P < 0.10; respectively), but not with hot carcass weight, ribeye area, or KPH (P > 0.10). Serum concentrations of leptin may be useful to objectively evaluate carcass composition in fed cattle and may provide a means by which carcass quality can be predicted in the live animal.
AN IMPROVED ASSAY FOR IDENTIFICATION of TYPE A CLOSTRIDIUM BOTULINUM USING the POLYMERASE CHAIN REACTION1
Authors: FERREIRA JOSEPH L. , HAMDY MOSTAFA K. , MCCAY STEVEN G. , BAUMSTARK BARBARA R.
Published: May 2007

The polymerase chain reaction (PCR) was used to amplify a 1340‐bp fragment from the toxigenic Clostridium botulinum type A chromosome. Two oligonucleotide primers were synthesized to bracket the sequence coding for most of the type A toxin light chain (1340‐bp in size). the PCR amplified a 1340‐bp fragment from the DNA of all eleven C. botulinum type A strains tested. In contrast, no DNA fragments were amplified from C. botulinum types B, E, and F or from the other Clostridial chromosomal DNA examined. the products amplifed from botulinal type A strains were digested to produce fragments of the size predicted from the known location of the Hind dIII sites within the toxin gene sequence. When used as a DNA probe, the 1340‐bp PCR generated fragment from type A C. botulinum strain 73A hybridized to the PCR products from all 11 type A botulinal strains and to type A thromosomal DNA preparations.
A 20–24 H MICROCOLONY‐IMMUNOBLOT TECHNIQUE to DIRECTLY DETECT and ENUMERATE LISTERIA MONOCYTOGENES INOCULATED INTO FOODS
Authors: BHUNIA ARUN K. , BALL PETER H. , JOHNSON MICHAEL G.
Published: May 2007

A microcolony‐immunoblot technique (MCIBI) was developed to directly enumerate, in less than 24 h, very low numbers of Listeria monocytogenes (8–12 colony forming units: CFU/g or mL) inoculated into foods. Four meat and poultry and two dairy products were artificially inoculated with L. monocytogenes V7 diluted and plated on Oxford agar medium. Each plate was overlaid with an Immobilon‐P membrane and incubated for 18–20 h at 37C. Blot‐transferred colonies on these membranes were probed with C11E9 monoclonal antibody (MAb) and developed using peroxidase conjugated goat antimo use Ig G and a water insoluble substrate (3,3‐diaminobenzidin tetrahydmchloride; (DAB‐HCI), Nickel chloride and H2O2). the MCIBT gave L. monocytogenes counts that were not significantly lower than direct colony counts on selective agars. This technique allowed the recovery of 94–100% of L. monocytogenes cells inoculated into foods containing natural background flora counts of 3 × 104 to 8 × 106 CFU/g or mL. Using a 2 h resuscitation period on nonselective agar before overlay with Oxford media, the MCIBT allowed detection of sublethally heat injured cells of strain V7.
A SIMPLIFIED METHOD of COLONY HYBRIDIZATION USING RADIOLABELED PROBES IN SEALED PETRI DISHES
Authors: BHADURI SAUMYA , FRATAMICO PINA M.
Published: May 2007

A simplified colony hybridization procedure was developed using sealed disposable plastic petri dishes in place of sealed plastic bags. Prior to hybridization, the dishes were sealed with successive layers of parafilm, plastic wrap and aluminum foil to prevent evaporation of the solution. This self‐contained procedure eliminates some of the technical problems such as spilling of radioactive materials, leakage of solution, sealing of plastic bags and the formation of air bubbles. Therefore, this method allows for safer and easier handling of radioactive materials during hybridization procedures.
THE APPLICATION of ATP BIOLUMINESCENCE FOR the ASSESSMENT of MILK QUALITY and FACTORY HYGIENE
Authors: BAUTISTA DERRICK A. , MCINTYRE LYNN , LALEYE LOUIS , GRIFFITHS MANSEL W.
Published: May 2007

The speed of ATP bioluminescence assays makes them very useful for assessing product quality and efficiency of sanitation at food plants. the suitability of a new method for evaluating the quality of raw milk was compared with plate count. A good correlation was obtained between the ATP method and plate count for milks with counts above 1 × 104 cfu/ml. the combination of ATP bioluminescence with preincubation procedures was investigated for predicting the shelf‐life of pasteurized milk. the best correlations were obtained when milks were preincubated at 15C for 25 h or at 21C for 25 h in the presence of an inhibitor system to prevent Gram‐positive bacterial growth.

Hygiene monitoring using bioluminescence gave a better indication of surface cleaniness than conventional swab counts. the reasons for the discrepancies in a small percentage of cases are discussed.
RAPID GM1 GANGLIOSIDE LATEX AGGLUTINATION SLIDE TEST FOR CHOLERA TOXIN1
Authors: YI PING‐CHENG , HARTMAN PAUL A.
Published: May 2007

In conventional latex‐particle agglutination tests, latex beads are either coated with antibody and clump if antigen is present in a sample or are coated with antigen and clump if an antibody is present in a sample. Ligands other than antigen and antibody have not been used previously for latex‐particle agglutination tests. We report here a new variation, a sandwich latex‐particle agglutination test in which interactions between GM1 gangliosides, antigen (cholera toxin) and anticholera antibody are used to affect agglutination. the principles that are described can be applied to develop tests for the rapid detection of other small ligands.
USE of OXYRASETM ENZYME IN ENRICHMENTS to ENHANCE the RECOVERY of ESCHERICHIA COLI O157:H7 FROM CULTURE MEDIA and GROUND BEEF1
Authors: PHEBUS R.K. , THIPPAREDDI H. , KONE K. , FUNG D.Y.C. , KASTNER C.L.
Published: May 2007

OxyraseTM membrane fraction was tested as an additive to nonselective BHI enrichment broth (0.1 unit/ml) to observe effects on growth of three strains of pathogenic Escherichia coli, including O157.H7 serotypes, and one nonpathogenic strain in culture broth and autoclaved ground beef systems. OxyraseTM enhanced the growth of all three pathogenic strains (inoculated at <1 cell/ml) in the broth system by shortening the lag phase period by 2–3 h. Growth of the nonpathogenic E. coli strain tested was suppressed by the presence of OxyraseTM during the initial 4 h of incubation at 37C in both broth and autoclaved ground beef systems. Stimulatory effects of the enzyme added at 0.1 unit/ml were not observed in autoclaved meat systems when E. coli strains were inoculated at 1–100 cells/g of meat during 24 h of incubation at 37C.

BHI broth alone and used as a nonselective enrichment for autoclaved and fresh ground beef was evaluated to observe the effect of OxyraseTM on the oxidation‐reduction potential (Eh) of each system after 0, 4 and 18 h of incubation at 37C. OxyraseTM slightly lowered Eh after 4 and 18 h in BHI broth and fresh ground beef (in BHI). However, no Eh‐decreasing effects were seen at this time in systems containing autoclaved ground beef which may explain the lack of a stimulatory effect of OxyraseTM on growth of E. coli in autoclaved ground beef.
THE USE of FLOW CYTOMETRY FOR RAPID IDENTIFICATION of SALMONELLAE
Authors: GOLDSCHMIDT MILLICENT C.
Published: May 2007

Flow cell cytometry can be used in a sensitive fluorescent immunoassay to rapidly identify salmonellae of Groups D and E. Staphylococcal Protein A couples with the Fc region of many antibodies, especially immunoglobulin G. When a fluorescent marker, fluorescein isothiocyanate, is conjugated to Protein A, an antibody‐antigen reaction can be visualized in a flow cell cytometer with an appropriate optical sensor after excitation. Ten thousand cells were individually analyzed in each cytometer run within a minute. the resultant data, presented as histograms and tables, indicated the number of cells in the suspension reacting positively with the antiserum by fluorescence, cell size, distribution and light scatter. This provides an in‐depth analysis of the antibody‐antigen reaction not possible with other types of immunoassays.
THE USE of FLOW CYTOMETRY FOR the RAPID CHARACTERIZATION of MONOCLONAL ANTIBODY PRODUCTION
Authors: GOLDSCHMIDT MILLICENT C.
Published: May 2007

Flow cell cytometry is reported here as a rapid fluorescent immunoassay method to characterize monoclonal antibody production in hybridoma cultures. Actinomyces viscosus was the bacterium chosen as a model to illustrate this procedure. Fluorescein isothiocyanate (FITC), coupled to staphylococcal Protein A (PA), was used as the fluorescent marker to detect and quantitate antigen‐antibody reactions. Flow cell cytometry was also used with rabbit polyclonal antibodies to A. viscosus coupled with PAFITC for comparison and verification of the two procedures. Over 25,000 individual bacteria could be analyzed in a single cytometer injection within 2 min. the data, presented as histograms and figures, supported the feasibility of this method and also provided an in‐depth analysis of the degree of fluorescence, cell size, distribution and light scatter not available with most other immunoassay methods.
BIOTIN‐AVIDIN ENZYME‐LINKED IMMUNOSORBENT ASSAY FOR BACILLUS SPORES IN BUFFER AND FOOD1
Authors: CHANG Y.H. , FOEGEDING P.M.
Published: May 2007

A biotin‐avidin enzyme‐linked immunosorbent assay (ELISA) was evaluated as a means to increase the sensitivity of a prototype ELISA developed to estimate bacterial spore populations. The method, based on a sandwich ELISA, incorporated a biotinylated rabbit anti‐B. cereus spore IgG and ExtravidinR‐alkaline phosphatase conjugate. The biotin‐avidin system increased sensitivity 2‐ to 4‐fold compared to the prototype method, which did not include an amplification step. Even with amplification, 106/ml or more spores were required for detection. Neither 0.5% starch nor 0.5% gelatin interfered with the biotin‐avidin ELISA compared to 1% bovine serum albumin in phosphate buffered saline (pH 7.4). Raw milk decreased the sensitivity of the assay by about 3‐ to 5‐fold.
COMPARISON OF THREE PROBE LABELLING METHODS TO DETECT PCR AMPLIFICATION PRODUCTS
Authors: PILLAI SURESH D. , JOSEPHSON KAREN L. , PEPPER IAN L.
Published: May 2007

Polymerase chain reaction amplifications are finding increased applications in environmental microbiology. The development of sensitive and specific methods to detect amplified products is necessary especially when these amplifications are conducted in the presence of the environmental matrix. Gene probes specific to the npt11 locus were prepared by nick translation, 5’end labelling and by a PCR driven amplification. These probes were tested against a 300 bp PCR amplified segment of the npt11 region of the transposable element Tn5. The nick translated probe was the most sensitive, though not as specific as the other two types of probes. Sensitivity and specificity were found to be dependent on the hybridization format (Southern blots versus dot blots), the number of amplification cycles and on the purity of the target sequence.
DEVELOPMENT AND CONFIRMATION OF CCP'S USING RAPID MICROBIOLOGICAL TESTS
Authors: STIER RICHARD F.
Published: May 2007

HACCP (Hazard Analysis and Critical Control Points) was conceived as a means of establishing the risk of Salmonella from foods in the early 1960s. The system, which has been called ‘a common sense approach to food safety,” has really only received the attention it deserves in the past three to five years. This increased attention happened to coincide with regulatory agencies'statements of intent to evaluate HACCP as a means of assuring the safety of foods produced in meats and seafood operations, respectively.

Developing and implementing HACCP in a food plant or throughout a corporation is a long‐term commitment. Maintaining the system and modifying as needed is absolutely essential HACCP principle. Rapid microbiological methods are among the more valuable tools available to companies who are considering implementing HACCP or have already done so. Potential and real applications of these technologies include risk assessment on ingredients, processing systems, and the plant, setting of limits for development of CCP's, some monitoring, evaluation of deviations, and verifying that the system is indeed working as designed. They can also be used by the HACCP team to evaluate any changes or proposed changes to the system.
COMPARISON OF MICROBIOLOGICAL METHODS FOR MONITORING CHICKEN CARCASS QUALITY
Authors: BAUTISTA DERRICK A. , CLARKE ROBERT A. , GRIFFITHS MANSEL W.
Published: May 2007

Many methods have been developed to determine microbial levels in food products and these include ATP bioluminescence, hydrophobic grid membrane filtration (HGMF), impediometry and turbidimetry. A comparison of these techniques for detecting microbial levels in chicken carcass rinses was conducted.

Only the ATP bioluminescence assay and the HGMF system showed a good correlation with plate counts (r = 0.82 and r = 0.83, respectively). The repeatability of these methods was acceptable. There was also a significant correlation between results obtained with two turbidimetric methods and HGMF as well as between HGMF and ATP bioluminescence data. However, only the ATP bioluminescence assay was able to provide results of microbial levels on a realtime basis (within 10 min). This would be beneficial for HACCP (Hazard Analysis of Critical Control Points) based programs.
A SEMI‐AUTOMATED COLORIMETRIC METHOD FOR DETERMINATION OF AMINOPEPTIDASE ACTIVITY IN TURBID SOLUTIONS 1
Authors: DIAS BENJAMIN , WEIMER BART
Published: May 2007

A semi‐automated colorimetric method to measure aminopeptidase activity using reflectance colorimetry is described. p‐Nitroanilide derivatives of 12 amino acids were used to detect aminopeptidase activity in phosphate buffer and milk. Enzyme activity, in phosphate buffer, determined using spectrophotometry and colorimetry, was linearly correlated (R2= 0.991), indicating colorimetry can be used in place of spectrophotometry to measure aminopeptidase activity. Aminopeptidase activity determined colorimetrically in buffer was linearly correlated (R2= 0.981) with activity in milk, indicating colorimetry can be used to detect enzyme activity in turbid solutions such as milk and dairy products. Optimum substrate concentration differed for milk and phosphate buffer. Assays in milk required higher concentrations of chromogenic substrates (0.8–1.0 mM), than did assays in phosphate buffer (0.3–0.5 mM). The assay was more repeatable in milk (average coefficient of variation = 3.6%) than in buffer (average coefficient of variation = 14.0%). Aminopeptidase activity of cell free extracts from Lactobacillus helveticus CNRZ32 were used to demonstrate the use of the assay. Enzyme profiles of this strain were similar in milk and in phosphate buffer. High activity was detected with p‐nitroanilide derivatives of arginine, lysine, leucine, alanine, and methionine.
USE OF UNIVERSAL PREENRICHMENT MEDIUM SUPPLEMENTED WITH OXYRASETM FOR THE SIMULTANEOUS RECOVERY OF ESCHERICHIA COLI O157:H7 AND YERSINIA ENTEROCOLITICA
Authors: THIPPAREDDI H. , PHEBUS R.K. , FUNG D.Y.C. , KASTNER C.L.
Published: May 2007

Universal Preenrichment (UP) medium was used successfully for the simultaneous recovery of two strains each of Escherichia coli O157:H7 and Yersinia enterocolitica in the presence of Listeria monocytogenes and Salmonella typhimurium. E. coli O157:H7 and Y. enterocolitica populations reached ca. 108 CFU/ml in UP medium in 18 h from an initial level ofca. 102 CFU/ml. Addition of OxyraseTM enhanced the growth of both E. coli O157:H7 strains and one strain of Y. enterocolitica. These three strains were able to recover from heat injury by 6 h when 24‐h cultures were tested, but not when 18‐h cultures were used. Injured and noninjured E. coli O157:H7 could be recovered from artificially inoculated food samples (shredded cheddar cheese, turkey ham, hot dogs, mayonnaise, and ground beef) in UP medium supplemented with OxyraseTM (UPO) by 18 h using immunoblotting. Y. enterocolitica could be recovered from turkey ham, hog dogs, and mayonnaise by direct plating on CIN agar from UPO medium. However, recovery of Y. enterocolitica from shredded cheddar cheese and ground beef required subsequent selective enrichment in sorbitol bile broth and isolation on Cefsulodin Irgasan Novobiocin agar (CIN). UPO medium can be used for simultaneous detection of E. coli O157:H7 and Y. enterocolitica from foods. However, subsequent selective enrichment and isolation on selective plating media are required for isolation of Y. enterocolitca from raw foods containing high population levels of background microflora.
GROWTH RESPONSE OF SALMONELLA SPP. TO CYCLOHEXIMIDE AMENDMENT IN MEDIA
Authors: HA S.D. , PILLAI S.D. , RICKE S.C.
Published: May 2007

The present study was designed to evaluate cycloheximide as a potential media amendment to prevent fungal overgrowth on selective media for salmonellae enumeration. The objectives were to determine the effect of cycloheximide on Salmonella spp growth rates and to determine the effect of cycloheximide addition on Salmonella enumeration in selective media. The bacteria tested included two strains of Salmonella typhimurium (NO/NA and LT2) and one strain of Salmonella arizonae. All strains were grown in tryptic soy broth containing cycloheximide to determine the effect of cycloheximide on bacterial specific growth rates. The growth rate of all strains grown in tryptic soy broth were not significantly influenced by addition of cycloheximide at concentrations up to 1,000 mg/L. Growth rates of S. typhimurium NO/NA in minimal media were significantly decreased by addition of cycloheximide aerobically (300 mg/L) and anaerobically (600 mg/L). However, S. typhimurium NO/NA populations on brilliant green agar, MacConkey agar, and from selenite cysteine broth and tetrathionate broth were not affected by cycloheximide additions at concentrations up to 1,000 mg/L. Cycloheximide has potential as a fungistat additive for salmonellae selective media.
EVALUATION OF THREE LATEX AGGLUTINATION TEST KITS FOR RAPID DETECTION OF CAMPYLOBACTER ISOLATES FROM CHICKEN SAMPLES
Authors: FANG SHAO W. , WANG CHAO H. , HUANG TSUI P. , SHIH DANIEL Y.C.
Published: May 2007

Three commercially available latex agglutination test (LAT) kits for the rapid identification of Campylobacter isolates were evaluated against 87 isolates of Campylobacter spp. and 46 strains of non‐Campylobacter bacteria (26 species). The performance of three LAT kits, MicroScreen® Campylobacter (Mercia Diagnostics, Shalford, UK), BBL CampyslideTM (Becton Dickinson Microbiology Systems, Cockeysville, MD, USA) and MERITECTM‐Campy (jcl) (Meridian Diagnostics, Cincinnati, OH, USA), were compared. All sensitivities for the three LAT kits were 100%. Specificities of both MicroScreen® Campylobacter and BBL CampyslideTM were 100%, but specificity of MERITECTM‐Campy (jcl) was only 89. 1/. The detection limit ranges (log CFU/ml) of MicroScreen®. Campylobacter, BBL CampyslideTM and MERITECTM‐Campy (jcl) against five Campylobacter strains were 7.7–9.1, 7.4–8.0 and 8.5–9.4, respectively. BBL CampyslideTM was more sensitive (10X) than the other two LAT kits (p < 0.01). A one‐day procedure was proposed to identify the suspicious colonies on selective agar by performing the LAT kit, catalase, oxidase and morphological observation.
MINIATURIZED ANALYTICAL METHOD FOR THE DETECTION OF AMINE PRODUCTION BY MICROORGANISMS
Authors: SOLER ANGEL A. , SALAS JESÚS , CHAPARRO MILDRED
Published: May 2007

Histamine, the result of histidine decarboxylation, has been associated with allergic reactions due to the consumption of certain foods. Other biogenic amines, such as putrescine and cadaverine, have been related to quality deterioration in foods. A quantitative miniaturized method for the detection of biogenic amines produced by microorganisms in culture media, was designed. The reaction takes place in microplates containing microquantities of inoculated media and reagents. Amine production is determined spectrophotometrically by monitoring changes in the acid phase of the pH indicator at 405 nm. Using the following amino acids: histidine, phenylalanine, tyrosine, tryptophan, arginine, lysine and ornithine, 44 microorganisms were tested for amine production. Sensitivity of the method is 10 μM of amine.
COMPARISON OF LUMINOL CHEMILUMINESCENCE WITH ATP BIOLUMINESCENCE FOR THE ESTIMATION OF TOTAL BACTERIAL LOAD IN PURE CULTURES
Authors: PIETRZAK E.M. , DENES A.S.
Published: May 2007

A rapid chemiluminescent assay of total bacterial load that is based on the oxidation of luminol (5‐amino‐2,3‐dihydro‐1,4‐phthalazinedione) as catalyzed by bacterial iron protoporphyrins is described and compared to the ATP bioluminescent assay of microbial biomass. An assay format that elicits linear light output response to a range of analyte concentrations of model compounds such as hematin and various heme‐containing enzymes within the dynamic range of a BioOrbit 1251 luminometer is presented. When the assay was applied to eight pure bacterial cultures, the sensitivity was typically in the range of 104‐105 cfu/ml, and was comparable to that obtained by the ATP assay. Similar levels of sensitivity can be derived from estimates of average values of 2.8 × 10‐18 mole of heme/cfu and 1 × 10‐19 mole of ATP/cfu. The potential of the luminal assay as an alternative rapid test for the estimation of total bacterial count in food and environmental samples is discussed.
IDENTIFICATION OF LACTIC ACID BACTERIA BY RIBOTYPING1
Authors: BREIDT FRED , FLEMING HENRY P.
Published: May 2007

Current methods that can be used for the identification of lactic acid bacteria (LAB) include: biochemical tests, pulsed field gel electrophoresis, and fatty acid analysis. These methods can be costly, time‐consuming, and technically difficult. We are investigating the microbial ecology of vegetable fermentations and are interested in the rapid identification of LAB isolates. We have adapted a PCR‐based ribotyping method for use with LAB. The PCR product (s) produced contains the sequences from the intergenie spacer regions between the rRNA genes. These products can be resolved by standard agarose or acrylamide gel electrophoresis. Using this method, we have identified PCR product electrophoresis banding patterns for the primary species of LAB found in vegetable fermentations, including those from the genera Lactobacillus, Leuconostoc, Lactococcus, and Pediococcus.
TEMPERATURE INDUCED SHIFTS IN THE FATTY ACID PROFILE OF STAPHYLOCOCCUS AUREUS WRRC B1241
Authors: BOWLES BOBBY L. , FOGLIA THOMAS A. , JUNEJA VIJAY K.
Published: May 2007

Variation in the fatty acid profile of Staphylococcus aureus WRRC B124 grown at varying temperatures was determined. The range of incubation temperatures tested induced both qualitative and quantitative differences in S. aureus fatty acid profile. While branched chained saturated fatty acids were the predominate species at 37C, C18:1 and C16:1 monounsaturated fatty acids were predominant at lower temperatures (12 and 19C). Iso‐branched C14:0, C16:0 and C18:0 saturated fatty acids were expressed exclusively at 37C and several C17:0 and C20:0 fatty acids were suppressed at 12C. Results demonstrated that S. aureus had altered fatty acid profile in response to changes in growth temperature.
NITROGEN‐LIMITED GROWTH RESPONSE OF RUMINAL BACTERIUM SELENOMONAS RUMINANTIUM STRAIN D TO METHYLAMINE ADDITION IN A MINIMAL MEDIUM
Authors: RICKE S.C. , SCHAEFER D.M.
Published: May 2007

Methylamine is often found as a naturally‐occurring metabolite in the rumen of sheep and cattle fed a variety of diets. The objective of this study was to examine the effect of methylamine on nitrogen‐limited growth of Selenomonas ruminantium strain D grown on a nitrogen‐free basal medium that would not support bacterial growth without the addition of a nitrogen source (ammonia, urea, glutamine, cysteine, or glutamate). In this medium S. ruminantium growth rates were significantly faster (P < 0.05) with 11 mM ammonia‐nitrogen than any other nitrogen source and were slowest on glutamate‐nitrogen (1 and 11 mM). Maximum optical density was greater (P < 0.05) for all nitrogen sources when the respective nitrogen source was increased from 1 mM to 11 mM nitrogen. Addition of 10 mM methylamine significantly decreased (P < 0.05) maximum optical density compared to the respective nitrogen source and concentration without added methylamine for cells grown on 1 mM glutamine‐, 1 mM cysteine‐, 11 mM ammonia‐, 11 mM glutamine‐, 11 mM cysteine‐ or 11 mM glutamate‐nitrogen. It appears that ruminal methylamine could decrease extent of growth of ruminal selenomonads depending on the nitrogen source(s) available for nitrogen assimilation.
MINIATURIZED ANAEROBIC CULTIVATION METHODS FOR RECOVERY OF CLOSTRIDIUM SPOROGENES FROM MEAT
Authors: KANG DONG HYUN , FUNG DANIEL Y.C.
Published: May 2007

Two new miniaturized methods (sandwiched microtiter plate [SMP] and mini‐tube) for recovery of Clostridium sporogenes from food samples were developed and evaluated. One hundred microliter of SFP (Shahidi Ferguson Perfringens) agar and 10 üL of diluted food sample were used in the SMP anaerobic system. The samples were sandwiched between two sterile microtiter plates to create an anaerobic environment. Black colonies in the sandwiched wells were counted as C. sporogenes. In case of mini‐tube system, 1 mL of SFP agar (45C) containing diluted food sample was aspirated into a 1.2 mL sterile pipet and allowed to solidify in place. The two ends are sealed to create an anaerobic environment. Black colonies were counted directly through the plastic tube. C. sporogenes was inoculated into ground beef samples for recovery study. The recovery rates in SFP agar, using the SMP and mini‐tube method were compared with the double‐tube method. Organisms were recovered more in the double‐tube than with SMP method and mini‐tube method after 24–30 h incubation. However, the final counts at 48 h were similar in all methods from the food samples. These new simple methods have potential use for recovery of Clostridium spp.
THE USE OF MICROBIAL MEMBRANES TO ACHIEVE ANAEROBIOSIS
Authors: ADLER HOWARD , SPADY GERALD
Published: May 2007

Several years ago, it was observed that sterile microbial membrane preparations stimulated recovery of certain radiation‐injured bacteria. Later it was noted that these same preparations reduce dissolved oxygen to water in a variety of environments, including bacteriological media. This reduction of oxygen is an enzymatic process and is influenced by parameters such as temperature, pH, and the availability of specific oxidizable substrates. Oxygenreducing membrane preparations can be made from several different bacterial species. When added to liquid or solid bacteriological media, membrane preparations rapidly produce and maintain anaerobic conditions favorable for the growth of a wide variety of oxygen‐sensitive microorganisms. When used with a specifically designed disposable dish, membrane preparations allow the development of colonies of many anaerobic microorganisms on the surface of agar without the use of anaerobic hoods or other devices. In addition to providing conditions suitable for the growth of anaerobes, membrane preparations stimulate recovery of heat and cold injured bacteria of several different genera including facultative organisms. These results are reminiscent of the early observations regarding the recovery of radiation‐injured bacteria. In addition to their usefulness in microbiology, oxygen‐reducing membrane preparations have the potential for protecting a wide variety of oxygen‐sensitive organic compounds.
APPLICATIONS FOR BACTERIAL MEMBRANE FRACTIONS IN STERILE PHARMACEUTICAL QUALITY CONTROL
Authors: CLAERBOUT MARK EUGENE
Published: May 2007

The commercially available bacterial membrane preparation Oxyrase was examined for use in quality control laboratory procedures for culturing anaerobic microorganisms, and as a media additive for parenteral product filling line validation by media fill to detect anaerobes. Comparison studies between Oxyrase products and conventional anaerobic culturing methods were performed. The results from the studies showed Oxyrase for Broth to be effective in promoting the growth of anaerobes in nonprereduced media not normally used for anaerobic cultivation.
METHODS AND RESUSCITATION ENVIRONMENTS FOR THE RECOVERY OF HEAT‐INJURED LISTERIA MONOCYTOGENES: A REVIEW1
Authors: HOFFMANS CYNTHIA M. , FUNG DANIEL Y.C. , KASTNER CURTIS L.
Published: May 2007

Bacterial cells may be damaged or injured when agents or processes that are meant to destroy them are inadequate. In optimum conditions, sublethal injury is reversible, and restoration of pathogenic potential can be total. Injured cells of Listeria monocytogenes are likely to escape detection, because current techniques are not appropriate for their recovery. This review addresses the role of L. monocytogenes in food poisoning issues, related cell injury and repair and methods for the recovery of heat‐injured cells, especially using aerobic micro‐aerophilic and anaerobic systems.
RAPID SCREENING FOR SALMONELLA IN FISHMEAL BY ENRICHMENT‐IMMUNOASSAY
Authors: NG S.P. , LI Z.G. , CHEN B.W. , QIN Z.K. , GARCIA M.M. , IM S.W.K. , NG M.H.
Published: May 2007

We previously described an enrichment‐immunoassay utilizing a T6 monoclonal antibody capture enzyme‐linked immunosorbent assay. Here we evaluated it for the rapid screening for Salmonella in fishmeal obtained from the national Animal and Plant Quarantine service in the People's Republic of China. In this method, the number of Salmonella present is first expanded by appropriate enrichment cultures, and the pathogens are then directly detected by the T6 immunoassay. In a total of 94 enrichment cultures of fishmeal, we obtained an overall concordance of 98% between the results obtained in parallel by this method and by conventional test method. The positive prediction by this method was 92% and the negative prediction was 100%. The turn around time for the new test was 27 h which is a significant improvement from the turn around time exceeding 96 h required for the conventional test method. This test proved to be compatible with the routine work flow in the practical setting of a quarantine laboratory.
COMBINATION OF DITHIOTHREITOL AND SULFIDE AS REDUCTANTS IN NITROGEN‐FREE MINIMAL MEDIA FOR GROWTH OF ANAEROBIC RUMINAL BACTERIA AND PREVOTELLA RUMINICOLA STRAIN B14 ON AMMONIA
Authors: RICKE S.C. , SCHAEFER D.M.
Published: May 2007

Cysteine is commonly employed as the medium reductant for ruminal bacteria, but many ruminal bacteria can use cysteine as a source of nitrogen as well as sulfur. The objective of the present study was to test a combination of dithiothreitol and sulfide as possible reductant substitutes for cysteine in anaerobic media containing ammonia as the nitrogen source. The type of reductant (cysteine versus dithiothreitol‐sulfide) and ammonia concentration did not alter growth rates of Prevotella ruminicola strain B,4 (P>0.15). However, growth rates in dithiothreitol‐sulfide reduced media varied tremendously between individual organisms ranging from 0.10 h−1 for Ruminococcus flavefaciens to 1.6 h−1 for Streptococcus bovis grown in 1 mM NH3‐N. At both 1 and 11 mM NH4Cl, Str. bovis strain JB1 exhibited the greatest growth rate followed by Str. bovis strain C277. Megasphaera elsdenii strain T81 and Ruminococcus flavefaciens strain FD1 had the lowest growth rates at both NH4Cl concentrations. Increasing NH4Cl concentration from 1 to 11 mM resulted in increased growth rates for Ruminobacter amylophilus strains H18 and 70 and Str. bovis strain C277 (P<0.05), and decreased growth rates for S. ruminantium subsp. lactilytica strain HD4 and Str. bovis strain JB1 (P<0.01). These results indicate that dithiothreitol and sulfide can be combined as reductants in nitrogen‐free basal media for most ruminal bacterial species.
IRON PRETREATMENT IS NOT ESSENTIAL FOR ASSESSMENT OF PATHOGENICITY OF YERSINIA ENTEROCOLITICA SEROTYPE O:3 IN MICE1
Authors: BHADURI SAUMYA , COTTRELL BRYAN
Published: May 2007

The effects of administration of iron‐dextran and the iron chelator, deferoxamine mesylate (Desferal), on the course and outcome of experimental yersiniosis were investigated in mice orally infected with pathogenic Yersinia enterocolitica isolated from contaminated pork samples. Experiments in which plasmid‐bearing Y. enterocolitica serotype O:3 food isolates were administered orally to mice at concentrations of 107 and 109 colony forming units per milliliter (CFU/mL) resulted in mice showing identical signs of disease with or without conventional iron‐dextran and Desferal treatment. This demonstrated that in mice inoculated with sufficiently high bacterial levels iron pretreatment was not essential for susceptibility to yersiniosis. Thus, a simplified and time saving murine virulence assay without iron pretreatment was found to be effective for determination of the pathogenicity of Y. enterocolitica serotype O:3.
THE CAPTURE OF ESCHERICHIA COLI O157:H7 FOR LIGHT ADDRESSABLE POTENTIOMETRIC SENSOR (LAPS) USING TWO DIFFERENT TYPES OF MAGNETIC BEADS1
Authors: TU SHU‐I. , UKNALIS JOE , GORE MITCHELL , IRWIN PETER
Published: May 2007

Two types of commercially available, streptavidin‐coated magnetic beads (SAMB) were labeled with the same biotinylated anti E. coli O157 antibodies. Labeled SAMB and other necessary antibody derivatives needed for Light‐addressable Potentiometric Sensor (LAPS) detection were used to capture E. coli O157:H7 in solution. The LAPS signal intensity was then used to determine the overall bacterial capture efficiency. The static and hydrodynamic properties of the beads were then used to correlate with determined efficiencies. It was found that the capture increased as the total mass of SAMB increased. Also, greater capture with SAMB of a higher density was observed with the same bead mass. In addition, the SAMB of higher density also required less time of rocking to reach a maximum capture. These observations are in agreement with the predictions from the hydrodynamic properties of tested SAMB.
BUOYANCY‐DEPENDENT IMB·SALMONELLA COMPLEX LOSSES DURING MAGNETIC PHASE SEPARATION1
Authors: IRWIN PETER , FORTIS LAURIE , CHAU LEE , TU SHU‐I
Published: May 2007

One question associated with the immuno‐magnetic bead (IMB) protocol for pathogen isolation and subsequent concentration is why a significant number of captured cells are lost during each magnetic separation step (MS). For instance, we observe an average IMB‐Salmonella concentration decrease of 4–7% per MS even at extremely low Salmonella Enteritidis cell densities ([S.E.] > 100 mL‐1; [IMB]:[S.E.]< > 1). Such a change in [IMB·S.E.] per separation step could be significant since, in practice, more washing/rinsing steps are necessary when isolating organisms from environmental samples. These apparent losses in pathogen activity are not due to the injury or decease of IMB‐bound bacteria inasmuch as numerous MS steps, accomplished without changing the supernatant, result in no significant diminution in bound Salmonellae. In this manuscript we show that [IMB·S.E.] losses monotonically increase from ca. 5 to 15% per MS with [S.E.]:[IMB]. These observations argue that MS‐dependent pathogen losses are related to changes in the buoyancy of the IMB·S.E. complex since, at elevated pathogen levels ([S.E.]:[IMB]> > 1), we observe as many as 4–6 Salmonella cells binding per IMB which could decrease the IMB·S.E. complex's density by about 8% or 0.1 g cm‐3.
A SUICIDE VECTOR FOR CONSTRUCTING A LYSA INSERTION MUTATION IN ESCHERICHIA COLI
Authors: LI X. , RICKE S.C.
Published: May 2007

The objective of this study was to construct an insertion mutation in the lysA gene of Escherichia coli and investigate the effect of the insertion mutation on the growth rate response. The lysA gene encodes the last enzyme in the lysine biosynthetic pathway in most bacteria. A suicide plasmid pXL1 carrying a segment of the lysA sequence was transformed into E. coli SM10 that is lysogenic for λ pir. The plasmid was extracted from the transformant and confirmed to contain the segment of lysA by restriction enzyme digestion. After this confirmation, pXL1 was transferred by conjugation to an E. coli strain that cannot support replication of the plasmid. Maintenance of the selectable drug marker on the plasmid requires that the plasmid integrate into the chromosome at the lysA locus. The constructed mutant could grow in the absence of lysine supplementation although its growth rate was significantly (P < 0.05) depressed when compared to the parent strain.
CONVENIENT METHOD FOR RAPID AND QUANTITATIVE ASSESSMENT OF SALMONELLA ENTERICA CONTAMINATION: THE MINI‐MSRV MPN TECHNIQUE
Authors: FRAVALO P. , HASCOËT Y. , FELLIC M. LE , QUEGUINER S. , PETTON J. , SALVAT G.
Published: May 2007

Direct assessment of Salmonella numeration is still a challenge in cases of numerous number of low Salmonella/competitive flora ratio samples. Nowadays the usable methods provide data with such large confident intervals that the obtained results do not justify the labor and time spent. So we developed a method based on miniaturization of the dilution, preenrichment and selective enrichment on MSRV steps and on automation as the transfers are performed with multichannel pipettes. This so called mini‐MSRV method provides a rapid and convenient way to assess the quantification Salmonella in studies providing many samples. After description of the method, this paper presents the results obtained from 3 different types of samples issued from 3 different steps of the production chain where quantitative assessment of the Salmonella risk may be useful.
ANTIMICROBIAL ACTIVITY OF SPICES 1
Authors: CEYLAN ERDOGAN , FUNG DANIEL Y. C.
Published: May 2007

Many of the spices and herbs used today have been valued for their antimicrobial effects and medicinal powers in addition to their flavor and fragrance qualities. Most of the foodborne bacterial pathogens examined were sensitive to extracts from plants such as cinnamon, clove, garlic, mustard, onion and oregano. The antimicrobial compounds in spices and herbs are mostly in the essential oil fraction. The Gram‐positive bacteria were more sensitive to the antimicrobial compounds in spices than Gram‐negative bacteria. The extent of sensitivity varied with the strain and environmental conditions imposed. Certain spices can have a direct effect on the rate of fermentation by stimulating acid production in starter cultures. Phenols, alcohols, aldehydes, ketones, ethers and hydrocarbons have been recognized as major antimicrobial components in spices. The antimicrobial activity and modes of actions of spices and their major antimicrobial components are reviewed.
REAL‐TIME POLYMERASE CHAIN REACTION FOR DETECTION OF STAPHYLOCOCCUS AUREUS AND PSEUDOMONAS AERUGINOSA IN PHARMACEUTICAL PRODUCTS FOR TOPICAL USE
Authors: ŠKOF ANITA , POLJAK MARIO , KRBAVČIČ ALEŠ
Published: May 2007

Real‐time PCR assays, based on LightCyclerTM hybridization probes technology, originally developed for detection of Staphylococcus aureus and Pseudomonas aeruginosa in clinical samples, were adapted to pharmaceutical products for topical use. After optimization experiments, the applicability of optimized PCR assays was assessed by testing 34 different pharmaceutical products for topical use in parallel with standard microbiological protocol according to European Pharmacopoeia. To reveal any problematic substances, which might inhibit PCR reaction, pharmaceutical products with as much different dosage forms as possible and of different composition were selected. Complete concordance between PCR and standard microbiological protocol results was obtained on a wide spectrum of pharmaceutical products. The adapted PCR assays can detect 1–10 CFU of both bacteria per gram or milliliter of pharmaceutical product in 26 h (including 24‐h enrichment), whereas standard microbiological methods require 5–7 days. Real‐time PCR assays proved to be efficient tools for rapid screening of S. aureus and P. aeruginosa in pharmaceutical products for topical use.
COMPARISON OF SOURNESS OF ORGANIC ACID ANIONS AT EQUAL pH AND EQUAL TITRATABLE ACIDITY
Authors: NOBLE ANN C. , PHILBRICK KELLIE C. , BOULTON ROGER B.
Published: May 2007

The sourness of six organic acids was compared by pair tests in binary acid solutions of equal pH and equal potential hydrogen ion concentration. Monoprotic lactic acid was more sour than three of the four acids against which it was tasted, while triprotic citric acid was less sour than the four other acids against which it was compared. Of the diprotic acid pairs which were evaluated, only one significant difference in sourness was observed; succinic acid was more sour than malic acid. No relationship between buffer capacity or hydrophobicity and intensity of sourness was observed.
SENSORY EVALUATION OF IRRADIATED BEEF AND BACON
Authors: RISVIK EINAR
Published: May 2007

Vacuum‐packed beef and bacon were treated with gamma‐ radiation (1–10 KGy) from CO60 and stored for 3 months at + 4°C. The samples were evaluated by a trained sensory laboratory panel, directly after irradiation, and after 3 months. Samples given 1.0 KGy and higher doses were found to be significant different from nonirradiated samples at both times of testing. A higher intensity of off‐taste, rancidity, metallic taste and sweetness, and a lower intensity of juiciness and color saturation were found in all the irradiated samples. Off‐taste and rancidity were found to increase with increasing doses, and were best explained when analyzed by Principal Component Analysis (PCA).
COMPONENT AND FACTOR ANALYSIS APPLIED TO DESCRIPTORS FOR TEA SWEETENED WITH SUCROSE AND WITH SACCHARIN
Authors: ROGERS NANCY M. , BARGMANN ROLF E. , POWERS JOHN J.
Published: May 2007

Component and factor analysis were compared as means of reducing scaled values for 10 descriptors of tea to two dimensions so that relations among the attributes could be visualized. The association diagrams yielded by the two methods were generally similar, and there were significant differences between the diagrams for English Breakfast, an 80:20 blend of English Breakfast and Sencha teas, Ceylon and Darjeeling teas. Bartlett's test for equality ofvariance‐covariance matrices was significant. When tea was equivalently sweetened with sucrose and with saccharin, the association diagrams were different. Preference and sweetness were highly correlated with each other and they had high com‐munality with the other attributes when saccharin was the sweetening agent. When sucrose was the agent, sweetness still had high communality with the other attributes, but preference did not, indicating preference was the result of interplay of all the attributes rather than a dominant one. The correlation matrices were not significantly at p= 0.05, but they were at 0.10.
NEUROPHYSIOLOGY AND HUMAN TASTE SENSATIONS
Authors: BOUDREAU JAMES C.
Published: May 2007

Taste sensations are of primary importance in food flavor. Any attempt to synthesize chemically the flavor of a natural food involves mainly taste active compounds. Many distinct taste sensations can be identified as associated with food compounds. Thirteen different taste sensations are discussed herein. These different taste sensations are differentiated on the basis of stimulus chemistry and peripheral nerve conveying the taste information. Neurophysiological examination of the peripheral nerves involved in taste reveals that the sensory neurons can, in any species, be subdivided into distinct neural groups. These different neural groups respond to distinct classes of chemicals and often display different neurophysiological characteristics. Altogether in four different species, nine functional neural taste groups can be distinguished. In many cases, these neural groups can be taken as analogs for the neural groups assumed to underly human taste sensations. Distinct human taste sensations can be considered to arise from the excitation or inhibition of different neural groups. For certain human taste sensations there are no animal neural analog groups; and for certain neural groups there are no analog human sensations.
A SEMI‐ASCENDING PAIRED DIFFERENCE METHOD FOR DETERMINING SENSORY THRESHOLDS OF ADDED SUBSTANCES TO BACKGROUND MEDIA
Authors: LUNDAHL D.S. , LUKES B.K. , MCDANIEL M.R. , HENDERSON L.A.
Published: May 2007

A testing procedure was developed to determine the concentration range including an absolute or difference threshold for a compound added to a background medium. Samples were arranged into three groups, each containing a labeled control and three randomly arranged samples. Random samples in each group included an unlabeled control and two samples containing adjacent concentration levels from a series of six increasing concentrations of the added substance. Groups were presented in ascending order by concentration of the added substance. Within each group, panelists rated each sample on a nine‐point intensity scale of difference from the labeled control. Group specific psychological errors in judgement were reduced by subtracting the unlabeled controls from the sample scores. Analysis of variance was applied to these data yielding separate estimates of variance for sample scores within groups. Sets of t‐tests from paired comparisons were used to construct a confidence statement regarding a threshold interval.
ADJUSTING TASTE SCORES FOR VARIATIONS IN USE OF SCALES
Authors: MILLER ALAN J.
Published: May 2007

A method is given for adjusting the scores of tasters when continuous graphicrating scales are used. Linear adjustments are made for both the location and scale differences of tasters.