bluuebunny/crossref_metadata_2025_split huggingface dataset:
CYTOTOXICITY ASSESSMENT OF BACILLUS STRAINS ISOLATED FROM STREET‐VENDED FOODS IN JOHANNESBURG, SOUTH AFRICA
Authors: MOSUPYE F.M. , LINDSAY D. , DAMELIN L.H. , VON HOLY A. 
Published: April 2007

ABSTRACT Twenty‐one isolates each of Bacillus (B.) cereus, B. licheniformis and B. subtilis from street foods, collected in central Johannesburg, were randomly selected to test for cytotoxicity against McCoy 5A Mouse cells using a 3‐(4,5‐dimethylthizol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, and observation by confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM). Forty‐eight percent of B. cereus, 33% of B. licheniformis and 19% of B. subtilis strains produced cytotoxic compounds. For B. cereus strains, all supernatants exhibiting cytotoxic effects were inactivated by heat treatment at 121C for 15 min. By contrast, 24% of B. licheniformis and 10% of B. subtilis supernatants exhibited cytotoxic effects following heat treatment. CSLM and SEM showed that McCoy cells treated with cytotoxic supernatants exhibited leakage and necrosis. Presence of B. cereus, B. licheniformis and B. subtilis in street foods in high numbers may pose potetnial safety risks due to production of cytotoxic compounds.
INACTIVATION OF ESCHERICHIA COLI O157:H7 ON INOCULATED ALFALFA SEEDS WITH OZONATED WATER UNDER PRESSURE1
Authors: SHARMA RATNA R. , DEMIRCI ALI , BEUCHAT LARRY R. , FETT WILLIAM F. 
Published: April 2007

ABSTRACT Alfalfa seeds inoculated with Escherichia coli O157:H7 (∼105 CFU/g) were subjected to low hydrostatic pressure. Seeds immersed in ozonated water at 4C were held at 8 and 12‐psi ozone pressure for 2, 4, 8, 16, 32, and 64 min. Alternatively, seeds were continuously sparged with ozone for up to 64 min and then held at 12 psi for 5 min. Controls consisted of sparging and pressurization with air. Thirty‐two minute treatments of continuous ozone sparging followed by pressurization of seeds at 12 psi for 5 min were repeated with the addition of four surfactants (Tween 20, Tween 80, SPAN 20, and SPAN 80) in the treatment water. Enumeration of E. coli O157:H7 on treated, untreated, and control seeds was done on tryptic soy agar supplemented with 50 μg/mL of nalidixic acid. The reduction in population of E. coli O157:H7 on seeds treated with the 8 and 12 psi hydrostatic pressure in ozonated water ranged from 0.74 −1.56 log10 CFU/g and 0.72 – 1.62 log10 CFU/g, respectively. Control treatments carried out with air pressurization of seeds resulted in maximum population reductions of 1.55 log10 and 1.83 log10 CFU/g for 8 and 12 psi, respectively. For seeds treated with continuous ozone sparging (2 – 64 min) followed by pressurization at 12 psi for 5 min, the highest reduction was 2.03 log10 CFU/g. Reductions were, however, not significantly different (P > 0.05) from control treatment (with air) which reduced the populations by 0.57 – 2.19 log10 CFU/g. The presence of surfactants during continuous sparging of water followed by pressurization at 12 psi was not beneficial. None of the treatments adversely affected the germination of the seeds.
HYGIENIC PARAMETERS, TOXINS AND PATHOGEN OCCURRENCE IN RAW MILK CHEESES
Authors: DE REU K. , DEBEUCKELAERE W. , BOTTELDOORN N. , DE BLOCK J. , HERMAN L. 
Published: April 2007

ABSTRACT In total, 71 samples of retail raw milk cheeses produced or imported in Belgium and samples of Belgian farmhouse cheeses were examined for cotiforms, β‐glucuronidase positive Escherichia coli, Escherichia coli O157, Staphylococcus aureus, Salmonella spp., Listeria spp. and Listeria monocytogenes. The presence of staphylococcal enterotoxins was investigated on samples with S. aureus counts higher than 103 cfu/g. The incidence of coliforms, β‐glucuronidase positive E. coli and S. aureus was higher in soft than in blue veined, semi‐hard, hard and fresh cheeses. Four mold‐ripened soft cheeses were positive for E. coli O157. One of the 4 cheeses was positive for verotoxin VT2. Staphylococcal enterotoxins were detected in 1 soft redsmear cheese, which was positive for L. monocytogenes. L. monocytogenes was also detected in one fresh cheese. Salmonella was not detected in any of the 71 raw milk cheeses.
EFFECT OF CHILLING AND FREEZING ON SURVIVAL OF VIBRIO PARAHAEMOLYTICUS ON FISH FILLETS1
Authors: VASUDEVAN PRADEEP , MAREK PATRICK , DAIGLE SCOTT , HOAGLAND THOMAS , VENKITANARAYANAN KUMAR S. 
Published: April 2007

ABSTRACTVibrio parahaemolyticus is a foodborne pathogen isolated from coastal waters of the United States, and from seafoods including fish. No information is available on the viability of V. parahaemolyticus on raw, chilled and frozen fish. A three‐strain mixture of V. parahaemolyticus was inoculated on fish fillets (pH 6.4) to obtain a bacterial load of 104 (high) or 103 (low) CFU/fillet, and stored at 4C or 8C for 9 days or at – 18C for seven weeks. At 4C and 8C, and at both levels of inoculation, V. parahaemolyticus survived on the fillets for the entire duration of the study. However, there was a significant reduction (P < 0.01) in V. parahaemolyticus population on the fillets by 9 days of storage. In the frozen fillets, there was a sharp decline (P < 0.01) in the population of V. parahaemolyticus by day 5 of storage. Although chilling and freezing significantly (P < 0.01) inactivated high numbers of V. parahaemolyticus on fish, they cannot be relied upon as a method to reduce V. parahaemolyticus on fish, since the time and magnitude of reduction depends on the initial load of the pathogen and the storage temperature.
IN VITRO COMPARISON OF ANAEROBIC AND AEROBIC GROWTH RESPONSE OF SALMONELLA TYPHIMURIUM TO ZINC ADDITION
Authors: PARK S.Y. , WOODWARD C.L. , BIRKHOLD S.G. , KUBENA L.F. , NISBET D.J. , RICKE S.C. 
Published: April 2007

ABSTRACT Zinc supplemented diets have been used to provide zinc as a nutrient and higher concentrations have been used to induce molt in laying hens. It is not known if the zinc in these diets would inhibit Salmonella spp growth. This study examines the effects of zinc compounds on the growth of S. typhimurium poultry isolate under aerobic and anaerobic conditions. The aerobic growth response of S. typhimurium was determined either in tryptic soy broth (TSB) or minimal (M9) broth containing five different concentrations (0.67, 2.01, 3.35, 4.69, and 6.03% [wt/vol]) of either Zn acetate [Zn(C2H2O2)22H2O] or Zn sulfate [ZnSO47H2O] while anaerobic growth response was determined in M9 broth with or without reductants (L‐cysteine hydrochloride [C3H7NO2SHCl], and sodium sulfide [Na2S 9H2O]). Aerobic growth rates inhibited (P < 0.05) by Zn acetate than by Zn sulfate in TSB medium. The Zn source and concentration decreased (P < 0.05) aerobic growth response of S. typhimurium poultry isolate in M9 medium. The growth rates of S. typhimurium under anaerobic growth conditions were less responsive to Zn salts but were generally lower (P < 0.05) in the presence of reductant than in the absence of reductants at each concentration of Zn compound. The results in this study provide evidence that Zn may inhibit S. typhimurium under in vitro aerobic or anaerobic atmospheric conditions and S. typhimurium grows less optimally under anaerobic growth conditions.
EFFECTIVENESS OF CHLORINE AND NISIN‐EDTA TREATMENTS OF WHOLE MELONS AND FRESH‐CUT PIECES FOR REDUCING NATIVE MICROFLORA AND EXTENDING SHELF‐LIFE1
Authors: UKUKU DIKE O. , FETT WILLIAM F. 
Published: April 2007

ABSTRACT Efficacy of nisin‐EDTA treatments as a sanitizing treatment for reducing native microflora of whole melons and extending shelf‐life of fresh‐cut pieces was compared to chlorine treatments. Whole cantaloupe and honeydew melons were washed with water, nisin (10 μg/mL)‐EDTA (0.02 M), or 200 ppm chlorine for 5 min at ∼ 20C before fresh‐cut preparation and storage at 5C for 15 days with periodic microbiological sampling. In addition, some fresh‐cut pieces were washed with 10 μg/mL nisin‐EDTA or 50 ppm chlorine for 1 min before storage. Changes in appearance, odor, overall acceptability and the shelf‐life of the minimally processed fresh‐cut melons were investigated. Preliminary studies indicated that water washes, EDTA (0.002 to 0.2 M) or nisin (5 to 10 μg/mL) were not effective in reducing the microflora of whole melon when used individually. Nisin‐EDTA and chlorine treatments were significantly (P < 0.05) more effective in reducing native microflora than water washes. Nisin‐EDTA treatments were significantly (P < 0.05) more effective than chlorine in reducing populations of yeast and mold and Pseudomonas spp. on whole melon surfaces but were not as effective as chlorine treatments for reducing aerobic mesophilic bacteria, lactic acid bacteria and total gram‐negative bacteria. Microbial contaminants on fresh‐cut pieces washed with 50 ppm chlorine or nisin‐EDTA were further reduced. However, microbial populations increased throughout refrigerated storage irrespective of treatments. Odor, appearance, and overall acceptability ratings for cantaloupe and honeydew fresh‐cut pieces treated with nisin‐EDTA or chlorine were not significantly (P > 0.05) different from each other throughout the storage period (15 to 21 days). However, both treatments led to significantly (P < 0.05) improved ratings compared to the controls for the fresh‐cut pieces at 9 to 12 days of storage and thereafter. The results of this study suggest that treatments with nisin‐EDTA before and after fresh‐cut processing would improve the quality and extend the shelf‐life of fresh‐cut melon.
ANTIMICROBIAL PROPERTIES OF NISIN‐COATED POLYMERIC FILMS AS INFLUENCED BY FILM TYPE AND COATING CONDITIONS
Authors: LEUNG PATSY P. , YOUSEF AHMED E. , SHELLHAMMER THOMAS H. 
Published: April 2007

ABSTRACTPolymeric films were coated with nisin, an antimicrobial peptide, for potential application in shelf‐life extension of food. Five commercial packaging films with varying surface energies were compared. The highest antimicrobial activity was observed on the most hydrophobic nisin‐coated films (surface energy ± 32 dyne/cm). The binding affinity of nisin to the surface of ethylene acrylic acid copolymer (surface energy = 32 dyne/cm) was investigated. Films were coated in nisin solutions under varying conditions including nisin concentration, contact time, solution's volume to film area ratio, pH of coating solution and temperature during coating. Stronger nisin activity was detected on films as the coating time increased from 30 s to 2 h. Higher nisin coating concentration also promoted the binding of nisin to films with saturation level observed at 250 μg/mL. Films coated with nisin using a higher solution to film area ratio (0.84 compared to 0.14 and 0.28 mL/cm2) also exhibited higher nisin activity.
A SURVEY OF THE PREVALENCE OF SALMONELLA AND OTHER ENTERIC PATHOGENS IN A COMMERCIAL POULTRY FEED MILL
Authors: WHYTE PAUL , McGILL KEVINA , COLLINS JOHN DANIEL 
Published: April 2007

ABSTRACTA study of the prevalences of Salmonella, Listeria and thermophilic campylobacters in a dedicated commercial poultry feed mill was undertaken. Salmonella was frequently recovered in samples taken in the preheat and postheat treatment areas of the mill with the overall percentage of samples positive found to be 18.8% and 22.6%, respectively. Feed ingredients and dust collected in the preheat treatment locations within the mill were frequently contaminated with Salmonella (11.8% and 33.3% of samples, respectively). High prevalences of Salmonella were also detected in dust samples (24.2%) obtained from the postheat treatment area of the mill and from feed delivery vehicles (57.1%).Listeria was also recovered from samples at pre‐ and postheat treatment areas within the mill with overall isolation rates of 14.1% and 18.5% observed, respectively. The most frequently observed species of Listeria recovered from samples in both areas within the mill was L. innocua, L. monocytogenes, L. grayi and L. welshimeri.No thermophilic campylobacters were recovered from any of the samples analyzed in the current study.
MODELING TEMPERATURE, pH, NaCl, NITRITE AND LACTATE ON THE SURVIVAL OF ESCHERICHIA COLI O157:H7 IN BROTH
Authors: WHITING R.C. , GOLDEN M.H. 
Published: April 2007

ABSTRACTA model was developed to estimate the survival times for a four‐strain cocktail of Escherichia coli O157:H7 in BHI broths with pH values from 3.5 to 7.0, NaCl from 0.5 to 15%, Na lactate from 0.0 to 2.0% and NaNO2 from 0 to 75 ppm. Broths were stored between 4 and 37C for up to 6 months. Samples were removed and enumerated at appropriate intervals. A primary level model with a shoulder period (no decline) and a subsequent log‐linear decline was fitted to the survival data and the times for 3, 4, 5, and 6 log10‐units of decline determined. A secondary level second‐order regression equation with the environmental conditions and declines being the independent variables was fitted to the survival times. Confidence limits about the estimated mean were also estimated. In foods with equivalent conditions that do not permit E. coli O157:H7 growth, this model provides an initial estimate of the survival times.
CHALLENGE STUDIES WITH PROTEOLYTIC CLOSTRIDIUM BOTULINUM IN YEAST AND CHEMICALLY LEAVENED CRUMPETS PACKAGED UNDER MODIFIED ATMOSPHERES
Authors: DAIFAS DAPHNE PHILLIPS , SMITH JAMES P. , BLANCHFIELD BURKE , CADIEUX BRIGITTE , SANDERS GREG , AUSTIN JOHN W. 
Published: April 2007

ABSTRACTChallenge studies were done with proteolytic Clostridium botulinum (103 spores/g) in yeast‐and chemical‐leavened crumpets (50‐g) packaged in air with an ethanol vapor (2‐G Ethicap®) generator or in 100% CO2 and stored at ambient temperature (25C) for 30 days. Neurotoxin was detected in all gas‐ (CO2) packaged crumpets after 5 days regardless of the method of leavening. While neurotoxin was delayed for 10 days in chemical‐leavened Ethicap®‐packaged crumpets, it was not detected in any similarly packaged yeast‐leavened crumpets throughout storage. This inhibition of growth and neurotoxin production by C. botulinum was attributed to the production of ethanol by Saccharomyces cerevisiae in the yeast leavened crumpets, in conjunction with the ethanol vapor generated by the Ethicap® sachets (2‐G), to levels to inhibitory to the growth of C. botulinum (>2.8% v/v). Subsequent challenge studies in sterile crumpets inoculated with either C. botulinum (103 spores/g) or a co‐inoculum of C. botulinum (103 spores/g) and S. cerevisiae (105 CFU/g) confirmed the significant role (p<0.001) of S. cerevisiae in enhancing the antibotulinal efficacy of ethanol vapor. These studies showed that the method of crumpet leavening could have a profound effect on the growth of and neurotoxin production by C. botulinum in crumpets packaged under modified atmospheres.
NOVEL NONTHERMAL METHODS TO REDUCE VIBRIO VULNIFICUS IN RAW OYSTERS
Authors: BORAZJANI ABDOLSAMAD , ANDREWS LINDA S. , VEAL CHARLES D. 
Published: April 2007

ABSTRACTVibrio vulnificus is a foodborne pathogen associated with consumption of raw oyster. No scientific data is available on postharvest treatments of oyster by ultrasound, ozone, and organic acids. This study was designed to investigate the effects of these treatments on inactivation of V. vulnificus naturally present in the in‐shell or half‐shelled oysters. In in‐shell oysters, these treatments were not effective in reducing the number of this pathogen. Half‐shelled oysters treated with ultrasound, and ozone in 2% saline for 30 min had 1 and 1.5 log less V. vulnificus, respectively (p<0.05). Treatment of half‐shelled oysters by 50 and 100% lemon juice, 5% citric acid, 10% citric acid, or vinegar for 30 min resulted in a significant reduction (2–4 log) in the numbers of V. vulnificus (p<0.05). Although these methods significantly reduced the population of V. vulnificus in raw oysters, they were not able to reduce the numbers of this pathogen to acceptable level (<3 MPN/g).
THE OCCURRENCE, HEMOLYTIC ACTIVITY AND ANTIBIOTIC SUSCEPTIBILITY OF MOTILE AEROMONAS SPP. ISOLATED FROM MEAT AND MILK SAMPLES IN TURKEY
Authors: YUCEL NIHAL , ÇITAK SUMRU 
Published: April 2007

ABSTRACTResearch was carried out to detect the incidence of motile Aeromonas species (A. hydrophila, A. caviae, A. sobria) in a variety of raw meat products (minced meat and chicken) and milk samples (raw and pasteurized) commonly consumed in Ankara. Motile Aeromonas species were isolated from 51.8% of samples detected; these were 40 (67.7%) of the 59 samples of minced meat, 20 (86.9%) of the 23 samples of chicken, 75 (47.7%) of the 157 samples of raw milk and 5 (16.0%) of the 31 samples of pasteurized milk. The dominant species were A.hydrophila and A.sobria in the meat samples, while A. hydrophila was the only isolated species in the milk samples. The strains identified as A. sobria or A. hydrophila were the stronger producers of hemolysin, whereas the A. caviae strains were nonhemolytic. The resistance of isolates to eight antibiotics was determined using the Kirby Bauer disc diffusion assay (Ciprofloxacin, Ceftazidime, Ampicillin, Cefixime, Cefoperazone, Erythromycin, Trimethoprim/sulfamethoxazole, Ceftriaxone). All aeromonads isolates (100%) were susceptible to ciprofloxacin but resistant to (100%) ampicillin and erythromycin. We found out that motile Aeromonas species are commonly present in milk and meat samples investigated in Turkey, which may pose a health problem to consumer. In addition, ciprofloxacin, cefoperozone, and ceftriaxone are suitable drugs that can be used in the treatment of Aeromonas‐associated infections, particularly in the immunocompromised, elderly people and young children.
INACTIVATION OF BACTERIAL SPORES BY COMBINED ACTION OF HYDROSTATIC PRESSURE AND BACTERIOCINS IN ROAST BEEF
Authors: KALCHAYANAND N. , DUNNE C.P. , SIKES A. , RAY B. 
Published: April 2007

ABSTRACTFoodborne bacterial spores are normally resistant to high hydrostatic pressure; however, at moderate pressure, they can be induced to germinate and outgrow. At this stage, they can be killed by bacteriocin‐based biopreservatives (BP‐containing pediocin and nisin at 3:7 ratio; BPX, BP + 100 μg/mL lysozyme; BPY, BPX+ 500 μg/mL Na‐EDTA). Based on this principle, spores of the meat spoilage organism, Clostridium laramie (1–2 × 102 spores/bag) alone or a mixture of four clostridial spores (5 × 103 spores/bag), Clostridium sporogenes, Clostridium perfringens, Clostridium tertium, and Clostridium laramie, were inoculated in roast beef in the presence of 5000 AU/g of bacteriocin‐based biopreservatives. The roast beef samples were subjected to hydrostatic pressure (HP) at 345 MPa for 5 min at 60C and stored at 4 or 12C for 84 days or at 25C for 7 days. The HP treatment of roast beef samples inoculated with a mixture of clostridial spores could be stored for 42 days at 4C. The HP in combination with either BPX or BPY extended the shelf‐life of roast beef up to 7 days at 25C. The combined treatment of HP and BP controlled the growth of C. laramie spores and extended the shelf‐life of roast beef for 84 days when stored at 4C.
SURVIVAL OF LISTERIA INNOCUA IN APPLE JUICE AS AFFECTED BY VANILLIN OR POTASSIUM SORBATE
Authors: CORTE FEDERICO V. , DE FABRIZIO SUSANA V. , SALVATORI DANIELA M. , ALZAMORA STELLA M. 
Published: April 2007

ABSTRACT Survival of stationary phase Listeria innocua (as surrogate microorganism for L. monocytogenes) inoculated in apple juice (pH 3.3 or 3.8) supplemented with vanillin (1,500 ppm or 3,000 ppm) or potassium sorbate (500 ppm or 1,000 ppm) and stored at room temperature was studied. L. innocua survived in apple juice without the preservatives at pH 3.3 or 3.8, with minimal population reductions. In the juices with the incorporation of potassium sorbate or vanillin, L. innocua behavior depended on the pH value, the type of antimicrobial and its concentration. At pH 3.3, the presence of vanillin (3,000 ppm) or potassium sorbate (1,000 ppm or 500 ppm) decreased L. innocua counts, with population reductions ranging from 4 to 5 log cycles after a 4 h – 8 h exposure at 30C. However, at pH 3.8, L. innocua showed sensitivity only to 3,000 ppm vanillin. Survival curves were successfully fitted using a Weibull type distribution of resistances. The results suggest that the use of potassium sorbate or vanillin could prevent the survival of L. innocua in contaminated unpasteurized and pasteurized apple juice. Vanillin, a natural antimicrobial, would be particularly suitable as an antilisterial additive for less acidic apple juice.
The Effect of Five Stocking Densities on Growth and Yield of Red Swamp Crawfish Procambarus clarkii
Authors: Lutz CHarles G. , Wolters William R. 
Published: April 2007

AbstractA 34‐day study was conducted to estimate the effect of stocking density on growth, biomass, and yield of harvestable animals in red swamp crawfish, Procambarus clarkii (Girard). Juvenile crawfish were stocked at l, 2, 4, 8, and 16 crawfish per m2 into plastic‐lined metal pools planted with rice (Oryza sativa) with three replicate pools at each density. Crawfish averaged 35 ± 1.5 mm (SE) total length at the time of stocking.Growth in total length and weight was significantly affected by density (P < 0.01), ranging from 91.5 mm and 20.7 g for crawfish stocked at 1 per m2 to 62.5 mm and 6.3 g for crawfish stocked at 16 per m2. The total crawfish biomass ranged from 20.7 g per m2 for crawfish stocked at 1 per m2 to 88.7 g per m2 at 16 per m2. The portion of that biomass made up of harvestable sized animals (>75 mm total length) ranged from 100% at 1 per m2 to 0.7% at 16 per m2. Gross revenues per ha were projected for crawfish yields at each stocking density with and without a graded product.
Shipping of Penaeid Broodstock: Water Quality Limitations and Control During 24 Hour Shipments
Authors: Robertson Lori , Bray William A. , Lawrence Addison L. 
Published: April 2007

AbstractShipping trials were conducted with adult Penaeus setiferus to determine the effect of 24 hour closed shipments on water quality, to evaluate methods of reducing water quality deterioration and to maximize packing density (biomass). Other trials were undertaken with juvenile P. setiferus and adult P. vannamei for comparison. The method utilized 8 L seawater chilled to 18–19 C, inside doubled polyethylene bags held in a Styrofoam box (42 × 42 × 23 cm deep). Gaseous O2 was injected into the water to 8 ppm (for standardization) and into the space above the water. Super‐saturation of dissolved oxygen (>20 ppm for 24 hours) had no adverse effect on survival. Initial trials resulted in increased ammonia (from 0.1 to 4–6 ppm NH4‐N), increased carbon dioxide (from <2 to 80–100 ppm), increased temperature (from 18–19 to 25–26 C) and decreased pH (from 8.0 to 6.0–6.4). Increases in shipping density (number or biomass of shrimp per L seawater) further intensified water quality deterioration. Carbon dioxide (with concomitant pH decline) is implicated as the major limiting factor during 24 hour closed shipment. Ammonia accumulation was reduced or totally eliminated with addition of AmQuelΘ (Kordon, Inc, Hayward, California),2 depending on the dosage used. The buffer, Trizma® 8.3 (Sigma Chemical Co, St. Louis, Missouri),2 limited CO2 buildup and reduced pH decline. Maintenance of low temperature over 24 hours was enhanced with addition of a frozen cold pack placed over the shipping bags. However, the control of ammonia, pH and carbon dioxide by the addition of AmQuel and Trizma did not increase survival, possibly due to toxic effects of the chemicals.