bluuebunny/crossref_metadata_2025 huggingface dataset:
SPIRAL SYSTEM AND LASER COLONY SCANNER FOR ENUMERATION OF MICROORGANISMS
Authors: MANNINEN M. T. , FUNG D.Y.C. , HART R. A.
Published: April 2007

Aerobic Plate Count (APC) and spiral plate (Spiral) methods using both manual counting (MC) and laser counting (LC) procedures were compared for pure bacterial, yeast, and mold cultures and raw milk samples. All four combinations of methods (APC‐MC, APC‐LC, Spiral‐MC, and Spiral‐LC) gave similar log10 counts of studied pure microbial cultures, producing results that were not different for the purposes of practical microbiology. With bacterial and yeast cultures, counts differed by less than half a logarithmic cycle (the range of difference = ‐0.26 to +0.42), the range of difference being ‐0.03 to +0.62 for Aspergillus flavus and Penicillium camemberti molds. An exception was noticed with Rhizopus oligosporus mold when plates were read by laser due to large (10–15 mm) colony size. The difference between the readings made manually and by laser colony scanner was about one logarithmic cycle with both APC and Spiral methods.

Statistical analyses of the manually read results of bacterial and Saccharomyces cerevisiae spiral plates showed no differences at the 0.05 level of significance between the readings made by four or five persons.

For raw milk samples, Spiral‐MC and Spiral‐LC methods gave higher microbial numbers than APC‐MC (63% of samples) and APC‐LC (54% of samples) at 0.05 level of significance (p<0.001). Of the LC results, 75% were within a ± 0.5 logarithmic cycle range when compared to MC results, of which 98% were within the same range. All results were still within a ± 1.0 logarithmic range. When APC and Spiral for raw milk samples were analyzed, LC gave higher microbial numbers compared to MC: 71% of the APC‐LC results were higher than APC‐MC results, and 85% of Spiral‐LC results were higher than Spiral‐MC results at 0.05 level of significance (p<0.001). 77% of the results by either plating technique were within a ± 0.5 logarithmic range.
IMPROVED ESTIMATIONS OF TOTAL AND PSYCHROTROPHIC MICROFLORA IN RAW MILK USING REFLECTANCE COLORIMETRY AT 32°C1
Authors: ZMARLICKI STANISLAW , YUAN T. C. JAMES , RICHARDSON GARY H.
Published: April 2007

A reflectance colorimeter with 32°C incubation/detection temperature successfully quantitated total and psychrotrophic microflora in raw milk. Correlations between reflectance colorimetry and the Standard Plate Count improved with preliminary incubation time: .50 (no preliminary incubation), .74 (24 h at 7°C), to .84 (48 h at 7°C). Correlations between reflectance colorimetry and the Psychrotrophic Bacterial Count were better than those achieved with the Standard Plate Count and improved: .53 (no preliminary incubation). 80 (24 h at 7°C), to .91 (48 h at 7°C). The 48 h preliminary incubation method would cost less and data would be available in 48 to 72 h compared to the 98 to 240 h for psychrotrophic plating methods. A second sample set (no preliminary incubation) could be analyzed to identify high‐count samples in less than 24 h. Color detection times following sample refrigeration for 24 h at 0, 4. and 7°C were significantly different from samples tested before refrigeration. Identical sample time/temperature storage conditions are suggested
POTENTIAL OF IRRADIATION TECHNOLOGY FOR IMPROVED SHELLFISH SANITATION
Authors: MALLETT JOHN C. , BEGHIAN LEON E. , METCALF THEODORE G. , KAYLOR JOHN D.
Published: April 2007

Ionizing radiation is shown capable of serving as an effective sanitizing treatment improving the sanitary quality of shellfish and providing an increased margin of safety for shellfish consumers. 60Co irradiation of the hard‐shelled clam, Mercenaria mercenaria, and the oyster, Crassostrea virginica, significantly reduced virus carriage numbers without unduly affecting shellfish survival rates or desirable organoleptic qualities. A D10 value of 2 kGy was determined for depletion of hepatitis A virus in clams and oysters as measured by in situ hybridization fluorescent foci and cytopathology enumeration methods. A D10 value of 2.4 kGy was determined for depletion of rotavirus SA11 in clams and oysters as measured by a plaque forming unit enumeration method. Study results showed ionizing radiation capable of providing an extra, highly effective safeguard of shellfish sanitary quality when combined with traditional depuration treatment. Data drawn from other studies is introduced which shows D10 values as low as 1.0 kGy effectively eliminate Vibrio cholerae, and V. parahemolyticus, from shellfish.
SURVIVAL OF SALMONELLA TYPHIMURIUM, LISTERIA MONOCYTOGENES AND INDICATOR BACTERIA ON COOKED UNCURED TURKEY LOAF STORED UNDER VACUUM AT 3°C
Authors: INGHAM STEVEN C. , TAUTORUS CHERYL L.
Published: April 2007

Sterile slices of cooked uncured turkey loaf were inoculated with 106 CFU of either Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, Enterococcus faecalis, Citrobacter freundii, Klebsiella pneumoniae, or Enterobacter cloacae. Inoculated samples were vacuum‐packaged and stored at 3 ± 1°C. Microorganisms were enumerated at 0, 3, 6, 9, 12, and 15 days on nonselective media. K. pneumoniae exhibited the least cold‐tolerance with a log10 1.70 decrease in numbers. The coliforms E. cloacae, E. coli, and C. freundii had a survival pattern similar to that of S. typhimurium, with population decreases of log10 0.65, 0.82, 1.13, and 0.79, respectively. E. faecalis and L. monocytogenes were significantly more cold‐resistant, with a decrease of log10 0.20 and no significant change in numbers, respectively. Survival of E. faecalis was not significantly (p < 0.01) different than that of L. monocytogenes, suggesting the use of enterococci as indicators of L. monocytogenes contamination of processed meats.
COMPETITION OF FOOD BACTERIA WITH LISTERIA MONOCYTOGENES DURING ENRICHMENT CULTURE
Authors: DALLAS HUGH L. , TRAN TONY T. , POINDEXTER CHRISTINE E. , HITCHINS ANTHONY D. , ROMANELL LAWRENCE J.
Published: April 2007

Thirty‐two foodborne bacterial isolates were tested as potential competitors of Listeria monocytogenes strain LM82 during enrichment because of their resistance to the selective agents in Listeria enrichment and isolation media. Competitive ability of each isolate was classified as weak, moderate, or strong by determining the ratio at which it masked identification of LM82 at an inoculation concentration of 10 colony forming units (CFU)/10 mL of Listeria enrichment broth. Of the competitive isolates identified, six were Enterococcus spp., two were Staphylococcus spp., and one was a Corynebacterium sp. Although several strains of Enterococcus faecium were examined, not all were competitive. Of six other bacterial strains associated with food fermentations and tested for competitiveness with LM82, one, a Gram‐positive tetrad, was competitive. This study showed that although food microfloral strains that are able to survive in enrichment and isolation environments are fairly common, they do not necessarily compete with Listeria. Not all strains in a competitive species are necessarily competitive.
QUALITATIVE CORRELATION OF THE MOUSE NEUROTOXIN AND ENZYME‐LINKED IMMUNOASSAY FOR DETERMINING CLOSTRIDIUM BOTULINUM TYPES A AND B TOXINS1
Authors: HUHTANEN C.N. , WHITING R.C. , MILLER A.J. , CALL J.E.
Published: April 2007

The efficacy of an enzyme‐linked immunosorbent assay for botulinal toxin using polyclonal antibodies was evaluated in relation to the standard mouse assay. Qualitative tests for toxin in a meat system inoculated with Clostridium botulinum and pure cultures of various aerobic and anaerobic bacteria showed that both the mouse neurotoxin and enzyme‐linked immunosorbent assays detected toxin in the samples. However the ratios of mouse:ELISA activity of culture supernatant toxins of C. botulinum showed wide disparity among strains of types A and B. Trypsin treatment resulted in a slight loss of ELISA activity but the mouse response increased.
CYCLOHEXYLAMINE RESIDUE IN VEGETABLES BLANCHED WITH PRIMARY STEAM
Authors: BACHE CARL A. , LISK DONALD J. , STOEWSAND GILBERT S.
Published: April 2007

The corrosion inhibitor, cyclohexylamine (CHA), is a common additive for steam generation systems. If primary steam directly contacts food during blanching, heating, or cooking operations the possibility exists that contamination of the food by CHA may result. In this study, snap beans and green peppers were blanched with steam containing CHA. A gas chromatographic method was developed and used to show the presence of appreciable residues of CHA remaining in the post‐blanched vegetables. The widespread replacement of primary steam generators with secondary systems for food blanching largely eliminates possible hazards to consumers. The known toxicologic properties of CHA are reviewed and the need for additional studies of possible food contamination or direct human exposure by other commonly used steam additives is emphasized.
INFLUENCE OF FRUIT MATURITY ON THE HYPOGLYCIN A LEVEL IN ACKEE (BLIGHIA SAPIDA)1
Authors: BROWN MARCIA , BATES R.P. , McGOWAN C. , CORNELL J.A.
Published: April 2007

Ackee fruit representing a range of maturities were analyzed for hypoglycin A (hyp A) content. Hyp A in the arilli (edible flesh) dropped from over 1000 ppm to undetectable (<0.1 ppm) as the fruit matured (i.e., pod colored up, split and opened fully). At all stages the seed contained appreciable hyp A, ∼ 1000 ppm, and the membrane mirrored aril levels. These analyses support earlier observations that unopened or partially opened ackee should not be consumed, whereas fruit which open naturally to > 15 mm lobe separation pose little health hazard, provided that all seed and membrane portions are removed. Bright red, full sized ackee should never be forced open for human use.
ESTIMATING DEPTHS OF BACTERIAL PENETRATION INTO POST‐RIGOR CARCASS TISSUE DURING WASHING
Authors: ANDERSON M.E. , MARSHALL R.T. , DICKSON J.S.
Published: April 2007

A method for predicting the depth of penetration of bacteria into various beef tissues was developed. Blue Lake, an insoluble dye, was used to simulate bacteria on the meat surface because movement of the Blue Lake into the meat tissue during spray washing could be easily visualized. The beef tissue surfaces studied were: (1) exterior lean, (2) exterior fat, (3) interior body cavity (peritoneum) and (4) cut tissue. The model indicated that many bacteria not removed during washing are driven into the beef tissue by the washing process. Interior body cavity tissue was most resistant to penetration followed by exterior lean and fat tissues, which were about equal in resistance. Cut surfaces were the most susceptible to Blue Lake penetration.
CONSUMER RESPONSE TO INFORMATION ON INTEGRATED PEST MANAGEMENT
Authors: BRUHN CHRISTINE , PETERSON SHIRLEY , PHILLIPS PHIL , SAKOVIDH NICK
Published: April 2007

Risk communication theory is used to address consumer concerns about food safety and pesticide residues. Risk perception is a function of actual hazard and “outrage”factors. If concerns are acknowledged and information is provided on how risks are being addressed, the outrage component of perception is reduced. Two 2‐min videos were prepared to present information on the environmentally responsive integrated pest management (IPM) approach to farming. The video was shown to a total of 197 consumers in controlled group settings. Although about 90% of participants expressed confidence in the safety of produce grown in California and the United States, 40% said they avoided some produce items due to safety concerns. Pre‐and post‐attitude assessments and group discussions documented a significant change in attitudes toward food safety, farming practices, and university efforts to help farmers. This project indicates that consumer concerns are significantly reduced when their knowledge of IPM practices is increased.
EFFECT OF A HIGHWAY'S TRAFFIC ON THE LEVEL OF LEAD AND CADMIUM IN FRUITS AND VEGETABLES GROWN ALONG THE ROADSIDES
Authors: IGWEGBE A.O. , BELHAJ H.M. , HASSAN T.M. , GIBALI A.S.
Published: April 2007

Samples of fruits (grapes, pomegranates, and tomatoes), and vegetables (onions, potatoes, and spinach) were collected directly from randomly selected commercial farms along the Tripoli‐Zawiya major road, at the appropriate harvest seasons, during the period of May through November 1988. The objective was to determine the extent of contamination of the crops with toxic heavy metals, lead and cadmium, from traffic emissions. For the purpose of comparison, similar crops were collected, within the same periods, from farms in Waddy Al‐Rabia, far away from any major road.

The samples were dry‐ashed, and analyzed using flameless Atomic Absorption Spectrophotometer (AAS).

The statistical analyses of the experimental data showed that the major road contributed significantly (P < 0.05) to higher concentrations of lead in all the crops examined; and also cadmium in all the crops except in potatoes. Vegetable crops were found to have higher contents of these two metals than the fruits. Substantial amounts of these metals could be removed by washing the samples with triple distilled water.
SUBCHRONIC TOXICITY STUDY OF EASTERN BLACK NIGHTSHADE (SOLANUM PTYCANTHUM) BERRIES IN SPRAGUE‐DAWLEY RATS
Authors: VOSS KENNETH A. , CHAMBERLAIN WILLIAM J. , BRENNECKE LUCAS H.
Published: April 2007

Species of the Solanum nigrum complex, including eastern black nightshade (S. ptycanthum Dun.), are common nuisance plants, and their berries often contaminate agricultural commodities. Black nightshade plants and their fruits contain solanaceous glycoalkaloids, but little information is available regarding their toxicity in vivo. Male and female rats were fed diets containing 0, 1, 5 or 25% (w/w) eastern black nightshade berries (BNB) for 13 weeks. BNB had no effect upon clinical appearance and behavior, body weight, food and water consumption, serum chemical profiles or organ weights. Gross or microscopic lesions related to BNB were not found. Anemia was present in high‐dose males after six weeks and in mid‐dose males, high‐dose males and high‐dose females after 13 weeks. Erythrocyte counts, hemoglobin concentrations and hematocrits of these groups were significantly decreased and averaged 81–93% of their respective control values. Erythrocyte counts, hemoglobin concentration and hematocrits of males fed 1% BNB, females fed 1% BNB and females fed 5% BNB averaged 94–97% of the control values after 13 weeks. These findings indicate that ingestion of low to moderate amounts of S. ptycanthum berries does not pose a significant health risk, although anemia may be a potential consequence of prolonged exposure to highly contaminated foodstuffs.
EFFECT OF CARBOHYDRATE CRYOPROTECTING AGENTS ON THE FORMATION OF N‐NITROSODIMETHYLAMINE IN SURIMI‐MEAT FRANKFURTERS1
Authors: PENSABENE JOHN W. , FIDDLER WALTER
Published: April 2007

Previous investigations of frankfuters substituted with Alaska pollock consistently showed that, after broiling, higher levels on N‐nitrosodimethylamine (NDMA) were found in the surimi containing frankfurters compared to those containing the corresponding washed mince. This was apparent in the 50%, but not in the 15% substituted frankfurters. The addition of the cryoprotecting agents, sucrose and sorbitol, to the washed mince to make surimi was the major difference in the two forms of fish. Model system experiments carried out, first in an aqueous pH 5.8 buffer and second, in a 50% fish‐meat simulated frankfurter system indicated that the combination of sucrose‐sorbitol increased and fructose‐sorbitol decreased NDMA formation. Frankfurters prepared with 50% washed mince and containing different carbohydrates showed that sucrose‐sorbitol gave higher NDMA values than fructose‐sorbitol, even though all the carbohydrates tested gave NDMA results higher than the control.
SURVIVAL AND GROWTH OF SELECTED MICROORGANISMS IN KHOA DURING PREPARATION AND STORAGE
Authors: SOHAL SAM , BLANK GREG , LEWIS MIKE
Published: April 2007

The survival of Escherichia coli and Staphylococcus aureus during the production of khoa, a heat concentrated Indian milk‐based product, was investigated. Heat processing of milk containing from 3.6 to 6.5% fat at either 63 or 73C eliminated all E. coli. Under similar processing conditions, S. aureus was recovered, but only when heated in milk at 63C containing 6.5% fat. Potassium sorbate (3000 ppm) appeared more effective in inhibiting the growth of selected yeast and molds in khoa at 7C, compared to ascorbic acid (3000 ppm). Reducing the water activity (aw) of khoa from 0.97 to 0.93 did not appear to enhance the preservative effect. The reduction of E. coli or S. aureus in khoa during prolonged storage at 6–7C, was less than one log cycle, regardless of awor preservative type. Survival of S. aureus in khoa appeared to be enhanced with a decrease in aw. The potential for pathogens to survive in khoa during processing should be taken into consideration when formulating heating protocols.
RELATIONSHIP BETWEEN FOODBORNE BACTERIAL PATHOGENS AND THE REACTIVE ARTHRITIDES
Authors: SMITH JAMES L. , PALUMBO SAMUEL A. , WALLS ISABEL
Published: April 2007

Certain individuals suffer complications after diarrheic episodes caused by Campylobacter, Salmonella, Shigella, or Yersinia. One of these complications may be a sterile arthritis such as reactive arthritis, Reiter's syndrome and anklylosing spondylitis. Reactive arthritis and Reiter's syndrome have been shown to have a bacterial etiology; however, such etiology, while suspected, has not been definitely confirmed for ankylosing spondylitis. These arthritides show a strong familial assocation and here, reactive arthritis, Reiter's syndrome and ankylosing spondylitis are characterized and the relationship of the diseases to the major histocompatility complex antigen, HLA‐B27, is described. Studies have indicated that there may be molecular mimicry between certain microbial antigens and HLA‐B27. Molecular mimicry is discussed in terms of its possible explanation of the etiology of the reactive arthritides. The roles of antibodies, lymphocytes, bacterial antigens, and stress proteins in the symptomology of the arthritides are reviewed.
EFFECT OF PROCESSING CONDITIONS ON THE FORMATION OF BIOGENIC AMINES AND ETHYL CARBAMATE IN SOYBEAN TEMPE
Authors: NOUT M.J.R. , RUIKES M.M.W. , BOUWMEESTER H.M. , BELJAARS P.R.
Published: April 2007

Tempe is a fermented soybean product originating from Indonesia. The effects of manufacturing conditions, i.e., soaking, boiling, fermentation and home cooking by stewing or frying, and the effect of pure cultures of microorganisms commonly occurring in tempe towards their production of toxicants like biogenic amines and ethyl carbamate were investigated. The level of biogenic amines in soaked soybeans was rather low (total < 280 ppm), and not significantly affected by boiling, but considerably increased by fermentation. The functional fungusRhizopus oligosporusmainly produced tyramine and some putrescine (total biogenic amines approximately 1800 ppm). With added inoculation ofKlebsiella pneumoniaeandTrichosporon beigelii,the total amount of biogenic amines increased slightly (2000, resp. 2100 ppm) with a shift towards cadaverine. With addedLactobacillus plantarum,a reduction of tyramine levels resulted in a considerably lower total level of biogenic amines (approx. 1000 ppm). Storage at 5C did not affect the level of biogenic amines, whereas at 25C, increased levels of putrescine were observed. Home cooking by stewing had little effect, but frying in oil resulted in significant decreases of both putrescine and tyramine. Preventive measures to keep biogenic amines at low levels in tempe are recommended. They include inoculation with selected lactic acid bacteria which cannot produce but can degrade biogenic amines, and frying instead of stewing of tempe. Ethyl carbamate levels were negligible (<11 ppb) in all treatments; this was attributed to the absence of significant concentrations of ethanol in the product.
MICROBIOLOGICAL STUDY OF ARZÚA CHEESE (NW SPAIN) THROUGHOUT CHEESEMAKING AND RIPENING
Authors: CENTENO J.A. , RODRIGUEZ‐OTERO J.L. , CEPEDA A.
Published: April 2007

Changes during production and ripening in the microbial flora of 11 batches of Arzúa, a soft cheese made from raw cow's milk, were investigated. The following microbial groups were counted on the surface and interior of the cheese: total viable count (TVC), lactic acid bacteria (LAB), halotolerant flora, enterococci, proteolytic enterococci, staphylococci, Staphylococcus aureus, Enterobacteriaceae, faecal coliforms, molds, yeasts, Listeria spp. and (in milk) Brucella spp. pH and water activity were also determined. TVC and LAB were, generally, more than 9 log (cfu/g). Enterococci counts increased gradually, reaching values in excess of 6 log units. Halotolerant flora and staphylococci remained practically constant throughout ripening, at 6–8 and 5–7 log units, respectively. Maximum Enterobacteriaceae and faecal coliform counts exceeded 7 and 6 log units, respectively. Brucella spp. were not detected in any of the milk samples. Listeria spp. were detected in four batches, and Listeria monocytogenes in two.
COMPARISON OF LAG TIMES OBTAINED FROM OPTICAL DENSITY AND VIABLE COUNT DATA FOR A STRAIN OF PSEUDOMONAS FRAGI
Authors: HUDSON J. ANDREW , MOTT SANDRA J.
Published: April 2007

Values were obtained for the lag times of a strain of the meat spoilage bacterium Pseudomonas fragi under a variety of cultural conditions by analyzing optical density (OD) and viable count (VC) data using the Gompertz equation. Lag times produced from OD data were shorter than those derived from VC data. Observations showed that during the lag phase, cell length increased before the cells began to divide, explaining the apparent earlier resolution of lag phase observed with the OD measurement technique. By linear regression the general equation:

Log (VC Lag time) = A + B.Log (OD Lag time)

where A = 0.344 and B = 0.868 was derived to interconvert OD lag times and VC lag times. This equation was applied to predicted lag times derived from models that had been constructed using optical density data and that are used to predict growth kinetics of cold‐tolerant pathogens on foods. With this adjustment, the models demonstrated an improved predictive ability when compared to measured values for growth of these pathogens on foods.
EFFECT OF SODIUM ACETATE OR SODIUM PROPIONATE WITH EDTA AND ASCORBIC ACID ON THE INACTIVATION OF LISTERIA MONOCYTOGENES1
Authors: GOLDEN M.H. , BUCHANAN R.L. , WHITING R.C.
Published: April 2007

Several organic acids or salts approved as food additives enhance the inactivation of foodborne pathogens such as Listeria monocytogenes. Although there has been research on the effects of individual organic acids on the inactivation kinetics of L. monocytogenes, little information exists on their activity when used in combination with other food additives. We undertook to characterize the effects of combinations of 90% sodium acetate or sodium propionate, two salts that inhibit L. monocytogenes, with 8% EDTA (disodium salt) and 2% ascorbic acid on the nonthermal inactivation of a three‐strain mixture of L. monocytogenes. Activity was assessed in Brain Heart Infusion broth (BHI) at various concentrations (0.0–2.0% w/v), pH values (3.0–4.5) and temperatures (4–28C). Samples were removed periodically for up to 175 days and viable counts determined. Survivor curves were generated using a logistics‐based inactivation model and used to calculate “time to a 4‐D (99.99%) inactivation”(t4‐D). The rate of inactivation was directly related to concentration of the acid mixture and temperature of incubation and inversely related to pH. The primary factor effecting inactivation rates was pH, followed by the concentration of the undissociated form of the primary organic acid (acetic or propionic). Evaluation of the mixture components individually and in combination indicated the components acted largely in an additive manner. The results indicate that combinations of primary and secondary organic acids and EDTA may have advantages for enhancing the inactivation of L. monocytogenes in refrigerated, mildly acidic foods, while avoiding organoleptic effects associated with excessive levels of single acids.
THE EPIDEMIOLOGY AND COSTS OF DISEASES OF PUBLIC HEALTH SIGNIFICANCE, IN RELATION TO MEAT AND MEAT PRODUCTS
Authors: SOCKETT P.N.
Published: April 2007

Meat and meat products are important vehicles of foodborne illness outbreaks in European countries. Salmonellas were the most commonly reported aetiology of infection, although the relative importance of other agents varied. The factors contributing to the increase in food poisoning and salmonellosis in England and Wales related both to foods eaten and their preparation. The implication of foods of animal origin as principle vehicles of infection was strengthened by reports associating these foods with outbreaks of human illness, and reports of salmonella infection in animals and poultry. The current increase in salmonella infection associated with poultry products suggests that reducing infection in, or contamination of poultry could significantly decrease human illness.

The problem of human salmonellosis is multi‐factorial. Trends are driven by both intrinsic factors relating to the microbiological quality of the food and standards of preparation, and extrinsic factors, such as ambient temperature, which amplify the intrinsic effects. Many of these factors may be amenable to preventive activities, including programs to reduce infection in animals and poultry and programs to educate the consumer in safe food handling.

The costs of human salmonella infection in England and Wales were estimated to be between £231 million and £331 million in 1988 of which £143 million to £205 million may have been associated with meatborne infection. Reductions in human illness, as modelled by irradiation of poultry meat, could give substantial economic gains.
THE ROLE OF INDICATOR SYSTEMS IN HACCP OPERATIONS
Authors: SHERIDAN JAMES J.
Published: April 2007

Many chemical and microbial indicators can be used to determine the safety and shelf‐life of meats. This paper considers their potential application as elements in an effective HACCP system. A range of chemical indicators, including lactic and acetic acids and citrulline are examined. Many of these are of limited value, although citrulline offers some potential. Microbially based indicators and systems including, a contamination index and the use of temperature function integration are discussed. The correlation to the growth of pathogens is outlined, with particular reference to the modelling of E. coli. The potential value of psychrotrophic and psychrophilic counts as process hygiene indicators in the prediction of meat and keeping quality is elucidated. The application of these systems in HACCP is presented, with particular emphasis on their value in monitoring and verifying critical control points. The value of developing more effective methods using rapid techniques in this area is highlighted.
OCCURRENCE OF POTENTIALLY PATHOGENIC VIBRIOS IN BIVALVE MOLLUSCS (MUSSELS AND CLAMS) FROM RETAIL OUTLETS IN THE NORTH OF SPAIN
Authors: SUÑÉN ESTER , ACEBES MARÍA , FERNÁNDEZ‐ASTORGA AURORA
Published: April 2007

Forty‐three samples of shellfish (22 mussels and 21 clams) purchased from retail outlets from February through October were tested for the presence of vibrios associated with human disease. Vibrio spp. was found in 51.16% of the samples. V. alginolyticus was the commonest Vibrio species found in the samples, followed by V. parahaemolyticus, V. fluvialis and V. cholerae non‐01. All V. parahaemolyticus isolated were Kanagawa‐phenomenon negative. Hemolytic activities were shown in all isolates of V. fluvialis and V. cholerae. Bacterial indicators of quality and safety were within permitted limits by authorities. The results indicate the potential risks of food poisoning associated with the consumption of raw or undercooked shellfish.
MICROBIOLOGICAL STATUS OF BEEF CARCASS MEAT IN INDONESIA
Authors: MUKARTINI SRI , JEHNE C. , SHAY B. , HARPER C.M.L.
Published: April 2007

The microbiological status of beef carcass meat was investigated at a traditional and a semi‐modern abattoir in Indonesia. Carcasses from the traditional abattoir were generally less contaminated than those from the semi‐modern abattoir. The average total aerobic viable bacterial count of carcasses produced at the traditional abattoir, (log10 3.62/cm2) was found to be significantly lower (p = 0.02) at the semi‐modern abattoir (log10 4.02/cm2). More than 70% of carcasses at both abattoirs were found to be positive for Escherichia coli (> 10 organisms/cm2), while Salmonellae were found on approximately 15% of carcasses at both locations.
FUSARIUM MOLDS AND THEIR MYCOTOXINS
Authors: DE NIJS M. , ROMBOUTS F. , NOTERMANS S.
Published: April 2007

An overview is presented covering the occurrence of Fusarium species in raw food and feed materials and the mycotoxins produced by these molds. A study of the literature (reported from 1969 until now) revealed the occurrence of over 60 Fusarium species in these raw materials. It appears that the most reported species occur worldwide and in a large variety of raw food products, such as cereals, vegetables and fruits. These Fusarium species occurring in samples are producers of toxigenic secondary metabolites of which more than 100 have been described. Most of them are referred to as mycotoxins of which trichothecencs (e.g., deoxynivalenol, nivalenol, T‐2 toxin, diacetoxyscirpenol), fumonisins and zearalenones are most frequently reported.
INABILITY OF HEAT STRESS TO AFFECT SENSITIVITY OF LISTERIA MONOCYTOGENES TO PEDIOCIN IN PORK
Authors: KHOJASTEH AZADEH , MURANO ELSA A.
Published: April 2007

The effect of heat‐shock (48C for 20 min) on sensitivity of Listeria monocytogenes Scott A to bacteriocin produced by Pediococcus acidilactici was evaluated. Exposure of Listeria to pediocin (68, 267 AU/ mL) resulted in lower number of survivors in the first 2 h of incubation in Trypticase soy broth at 37C compared with samples without pediocin, regardless of whether the cells were heat‐shocked or not. Further incubation for 24 h resulted in resumption of growth by L. monocytogenes, with counts reaching the same level as samples without pediocin. Cold storage of Listeria in pork in the presence of pediocin (8,192 AU/g) resulted in a 2.0 log10 reduction after 24 h, when compared with controls not exposed to pediocin, regardless of whether the samples were stored under air, vacuum, or a modified atmosphere. Prior heat‐shocking did not have an effect on sensitivity of Listeria to pediocin during storage. Thus, storage atmosphere and exposure to heat shock, which are known to induce thermotolerance in L. monocytogenes, had no effect in sensitivity of this organism to pediocin.
PREVALENCE OF ANTIMICROBIAL RESIDUES IN PREPROCESSED AND PROCESSED COWS' MILK IN TRINIDAD
Authors: ADESIYUN A.A. , WEBB L.A. , BALBIRSINGH V.
Published: April 2007

The prevalences of antimicrobial residues were determined in cows' bulk raw milk from 16 collection centers, in pasteurized milk obtained from sale outlets, and in raw, pasteurized and sterilized milk in the processing line of a plant in Trinidad. The Delvotest SP 5 Pack test kits were used to detect the antimicrobial residues in milk. Thirty‐one (10.3%) of 300 bulk milk samples contained antimicrobial residues with penicillin responsible for 90.3% of all the positive samples which originated from 8 (50.0%) of the 16 collection centers. The prevalence of residues in pasteurized milk was 21.3% compared to 8.3% detected in sterilized milk. The difference was not statistically significant (P ± 0.05; X2). Pasteurized milk obtained from sale outlets but originating from two other processing plants had antimicrobial residue prevalence of 0% and 8.3%, respectively. It is concluded that the presence of antimicrobial residues in raw and processed milk in Trinidad could be of public health and economic significance.
VOLATILE FATTY ACID SENSITIVITY OF VEILLONELLA CF3 FROM A CONTINUOUS‐FLOW PROBIOTIC CULTURE
Authors: KWON Y.M. , SALINAS J.R. , DURANT J.A. , NISBET D.J. , RICKE S.C.
Published: April 2007

Veillonella CF3 which was isolated from chicken cecum as part of an anti‐ Salmonella competitive exclusion culture and produces significant amounts of propionic acid was used to examine growth and survival response to short‐chain volatile fatty acids. Growth rate of Veillonella CF3 was significantly (p < 0.05) decreased by exposure to propionate and butyrate (20–150 mM), while increased by addition of acetate (20–60 mM) during cultivation in anaerobic Viande Levure broth at pH 7.0. As determined by percent survivors of Veillonella CF3 in the presence of acetate, propionate or butyrate at pH 5.0, butyrate was highest in bactericidal activity, while acetate was least. Survival patterns during incubation at pH 5.0 with propionate, which seems to exert major antibacterial activity in the cecum, showed that Veillonella CF3 could multiply and survive during prolonged incubation with propionate lower than 100 mM following an initial decrease in viable cells. However, no viable cells were recovered after six days at concentrations higher than 200 mM. The results indicate that this probiotic Veillonella CF3 strain may possess adaptive mechanisms for survival against high concentrations of propionate, which are initially bacteriostatic to the Veillonella strain.
IDENTIFICATION OF HAZARDOUSFUSARIUMSECONDARY METABOLITES OCCURRING IN FOOD RAW MATERIALS
Authors: DE NIJS M. , VAN EGMOND H.P. , ROMBOUTS F.M. , NOTERMANS S.H.W.
Published: April 2007

Hazardous secondary metabolites produced byFusariummolds were identified in the first step of a risk assessment procedure, the hazard identification. These mycotoxins are excreted, often simultaneously, by the fungus into plant tissue. A literature survey revealed the occurrence of 61Fusariumspecies in agricultural produce (cereals, vegetables, fruits) of which 35 species were reported to produce a total of 137 secondary metabolites in laboratory experiments. This literature review shows that 41 (30%) of these secondary metabolites have been tested and found toxic in various assays and should be considered hazardous if present in food. Six of these were reported to be related to human intoxications. Four metabolites belonged to the trichothecenes (T‐2 toxin, nivalenol, deoxynivalenol and acetyldeoxynivalenol), the others were zearalenone and fumonisin B1. Twelve metabolites, including the previously mentioned six, were reported to have been tested in feeding trials using vertebrates. These twelve secondary metabolites should be regarded as most important and need to be evaluated in each risk assessment procedure for mycotoxins in food commodities.
CHALLENGE STUDIES WITH CLOSTRIDIUM BOTULINUM TYPE E IN A VALUE‐ADDED SURIMI PRODUCT STORED UNDER A MODIFIED ATMOSPHERE
Authors: LYVER ANDRÉ , SMITH JAMES P. , NATTRESS FRANCES M. , AUSTIN JOHN W. , BLANCHFIELD BURKE
Published: April 2007

Challenge studies were carried out on raw, cooked, and sterilized surimi nuggets, inoculated with 104spores/g of C. botulinum type E spores. All products were packaged in air and air with an Ageless SS oxygen absorbent and stored at 4, 12 and 25C. Toxin was not detected in any raw product throughout storage (28 days). The absence of toxigenesis was attributed to the low pH (4.1–4.3) due mainly to the growth of lactic acid bacteria (107CFU/g). Toxin was also not detected in any cooked product after 28 days. Product pH did not decrease as previously (due to the absence of LAB), but counts of C. botulinum still decreased throughout storage.

In sterile nuggets, C. botulinum counts increased to 106 cfu/g at both 12 and 25C, respectively, by 28 days. Lactic acid bacteria and Bacillus spp.were not detected throughout the 28 days storage period. Toxin was detected by days 28 and 14 at 12 and 25C, respectively, and toxigenesis preceded spoilage. The absence of toxin in cooked nuggets was attributed to the anti‐botulinal role by Bacillus species, the predominant spoilage bacteria in cooked nuggets.
HIGH PRESSURE INACTIVATION OF SACCHAROMYCES CEREVISIAE, ENDOGENOUS MICROFLORA AND PECTINMETHYLESTERASE IN ORANGE JUICE1
Authors: PARISH MICKEY E.
Published: April 2007

Decimal reduction times (D‐values) for Saccharomyces cerevisiae ascospores inoculated into pasteurized orang juice ranged from 4 to 76 s at pressures between 500 and 350 MPa. At the same pressures, D‐values of S. cerevisiae vegetative cells ranged from 1 to 38 s while those for the native microflora in nonpasteurized Hamlin orange juice were between 3 and 74 s. Corresponding z‐values were 123, 106 and 103 MPa for ascospores, vegetative cells and native microflora, respectively. Native microorganisms that survived high pressure treatments included yeasts, gram‐positive and gram‐negative bacilli. Pectinmethylesterase activity in nonpasteurized Hamlin orange juice was reduced to 5% of initial activity after 30 s at 900 MPa.
ADENOSINE TRIPHOSPHATE ENHANCES THE FLUORESCENCE OF 4′,6‐DIAMIDINO‐2‐PHENYLINDOLE (DAPI)‐LABELED ESCHERICHIA COLI O157:H71
Authors: TU SHU‐I , PATTERSON DEIDRE , UKNALIS JOE
Published: April 2007

Live cells of E. coli O157:H7 were labeled by 4′,6‐diamidino‐2‐phenylindole (DAPI) in buffers of different pH. The extent of labeling was relatively insensitive to pH in the range of 6.5 to 9.5. The fluorescence intensity of ± 104 DAPI‐labeled bacteria per mL in optical cuvettes could be detected by a luminescence spectrometer. With a fluorescence microplate reader attachment, less than 103 of labeled bacteria could be measured. DAPI‐labeling inhibited the growth and respiratory activities of the bacteria. The addition of 0.5 to 6 mM concentrations of ATP induced a substantial increase in the fluorescence of labeled bacteria. Maximal enhancement by ATP was observed from bacteria still maintaining low levels of physiological activities. The enhancement favored more alkaline media with pH greater than 9. A replacement of ATP with ADP or AMP diminished the extent of enhancement. Other triphosphate nucleotides did not enhance fluorescence of DAPI‐labeled bacteria. Comparable ATP enhancements were also observed with Pseudomonas alcaligenes and Shewanella putrefaciens. Solubilization/destruction of cell membranes of labeled bacteria by detergents essentially eliminated the ATP enhancement. Absorption and fluorescence spectroscopic measurements indicated that ATP could interact with free and bound DAPI. These results suggest that observed ATP enhancement in fluorescence intensity of DAPI labels in intact cells may be applied to increase the sensitivity of microorganism detection.
A QUANTITATIVE MICROTITER PLATE HEMOLYSIS ASSAY FOR LISTERIA MONOCYTOGENES
Authors: SAMPATHKUMAR B. , TSOUGRIANI E. , YU L.S.L. , KHACHATOURIANS G.G.
Published: April 2007

All virulent strains of L. monocytogenes produce the extracellular SH‐activated hemolysin, listeriolysin O, while nonhemolytic strains of L. monocytogenes are avirulent suggesting that the expression of this hemolysin is necessary for virulence of L. monocytogenes. Hence, testing for hemolysis becomes clinically relevant for an isolate identified as L. monocytogenes. However, the quantification and interpretation of this characteristic on blood agar poses several problems. Hence we have proposed a simple quantitative microtiter plate hemolysis assay. The assay is made of SRBC (3% SRBC in PBS) in microtiter plates to which CASO‐cultured cell‐free supernatants of L. monocytogenes or other test cultures are added. After mixing, the plates are incubated at 37C for 15–30 min and the hemolysis is visually read as CHU and MHU, as well as by a 620 nm scan for absorbancy. Percent hemolysis is calculated. We feel that this assay should prove to be of significance in a microbiology laboratory in which routine hemolysis assays are conducted.
MICROBIOLOGICAL QUALITY OF THE DAIRY PRODUCT PEDHA AND ITS IMPROVEMENT USING GAMMA RADIATION
Authors: BANDEKAR JAYANT , KAMAT ANU , THOMAS PAUL
Published: April 2007

Eighteen pedha samples procured from A and B grade retail shops were examined for their overall microbiological quality and for the presence of foodborne pathogens viz. Staphylococcus aureus, Salmonella sp., Coliforms, Listeria monocytogenes, Yersinia enterocolitica and Bacillus cereus. The microbiological quality of pedha samples from B grade shops was very poor as compared to pedha from A grade shop as evidenced by the very high total bacterial counts (6 × 107 cfu/g), high counts of S. aureus (as high as 7 × 106 cfu/g) and presence of coliforms and Listeria and Yersinia sp. in 33% of the samples. All the samples from A grade shops were also positive for S. aureus though negative for coliforms, Yersinia, Salmonella, Listeria and B. cereus. Gamma irradiation of pedha at a dose of 3kGy at 0C reduced overall bacterial load by five log cycles and S. aureus and coliforms could be totally eliminated. However, 5 kGy dose was necessary to eliminate S. aureus if the initial number exceed 1 × 105 cfu/g. Inoculated pack studies confirmed that 3 kGy dose was sufficient for the complete elimination of up to 1 × 105 cfu/g of S. aureus. A dose of 3 kGy had minimal effect on the sensory quality of pedha and even pedha samples irradiated at 5 kGy dose were acceptable. Treatment with 3 kGy dose of gamma radiation totally eliminated S. aureus and coliforms in pedha, thereby ensuring their microbial safety.
RESIDUE TESTING AND CONTROL STRATEGIES
Authors: MACNEIL JAMES D.
Published: April 2007

The need for residue testing and controls basically derives from two imperatives, the safety of the food supply and requirements imposed in trade. Maximum residue limits (MRLs) for pesticides, veterinary drugs, intentional food additives and potential contaminants, such as mycotoxins, are set for various food commodities based on toxicological assessment. Regulatory testing on domestically produced goods reveals the prevalence of a particular residue in a specific food commodity and also serves as a means to assess the effectiveness of the product registration system, while testing conducted on imports is primarily a verification of the effectiveness of the regulatory program in the exporting country. For industry, testing is required to demonstrate due diligence or to ensure that a product meets the specifications of an export market or a specific contract. Testing programs should be appropriate to meet the intended use. A survey to determine incidence of violations requires a test that detects residues above the MRL, while a dietary exposure study requires methodology that detects residues with the maximum achievable sensitivity. Tests conducted to certify a product for export or to fulfill the requirements of a contract should ensure that the product is in compliance with the market or contract requirement. If the requirement is “no detectable residues”, a very sensitive test method may be required. In many countries, there is a developing consensus that while government has a role in conducting work that is in the public interest, such as ensuring the safety of the food supply within a level of statistical assurance, it is ultimately the producer of the food who is responsible for the safety of the product or for ensuring that the product meets market or contract requirements. Various aspects of this changing regulatory, trade and consumer environment will be considered, with examples of the roles now played by governments and industry to ensure the safety and quality of food products.
CONTROLLED QUALITY MEAT: THE DUTCH EXPERIENCE
Authors: BEKMAN HENK
Published: April 2007

During the last few years there is a growing feeling in the Dutch livestock and meat industry that it is essential to change from a product oriented to a more market‐oriented production (from quantity to quality). This is mainly due to developments such as a more intense international competition, stagnant or declining meat consumption and negative pressure on the consumers’ image of meat. Counteracting these developments is only possible if every part of the production chain contributes (in close cooperation with each other) to achieve a better control of the whole production process: from conception to consumption. For a number of years an extensive research program has been carried out to set up a system of Integrated Quality Control (IKB). This has led to a “total quality concept” which includes the safety and quality of the product, the production method, care for the environment, and human and animal health. This paper discusses the basic elements (structure and content) of this quality concept. The extent of implementation of the IKB‐concept depends on the particular sector, but it is at around 70% for pigs and broilers. For IKB in veal, current participation is over 90%.
EDIBLE COATING AS PRESERVATIVE CARRIERS TO INHIBIT YEAST ON TAIWANESE‐STYLE FRUIT PRESERVES
Authors: CHEN MIN‐JANE , WENG YIH‐MING , CHEN WENLUNG
Published: April 2007

Edible coatings composed of methyl cellulose, glycerol, and fatty acid (stearic acid or palmitic acid) were tested as the preservative carriers for inhibition of surface microbial growth on Taiwanese‐style fruit preserves. These intermediate moisture foods, preserved by high sugar concentrations, spoil mainly by osmophilic yeasts growing on the surface. Two types of fruit preserves (Ten‐shing mei and Ching‐shuan mei) prepared from plum were covered with edible coatings containing benzoic acid. Two osmophilic yeasts (Zygosaccharomyces rouxii and Zygosaccharomyces mellis) were used as testing microorganisms. Yeast growth was inhibited when both fruit preserves contained 50–100 μg of benzoic acid (per gram). Furthermore, fruit preserves covered with edible coating showed no differences compared to uncoated samples in sensory evaluation. The results suggested that edible coating could serve as food additive carriers.
CAMPYLOBACTER JEJUNI: A BACTERIAL PARADOX
Authors: SOLOMON ETHAN B. , HOOVER DALLAS G.
Published: April 2007

Campylobacter jejunihas become recognized worldwide as a leading cause of diarrheal disease and foodborne gastroenteritis. Contaminated water, raw milk, and poultry appear to be the most common vehicles of transmission ofC. jejuniin humans. It is estimated thatC. jejunicauses between one to seven million cases of enteritis per year in the United States, resulting in 100 to 500 deaths. Although some people believeC. jejunicauses more cases of food poisoning than any other single agent, C. jejunihas been demonstrated to be extremely susceptible to a wide variety of antimicrobial treatments, food processing methods, and environmental stresses, in addition to being difficult to culture and maintain in the laboratory. The focus of this paper is to overview the current status ofC. jejuni,its epidemiological aspects, the fundamentals of its virulent capabilities, as well as to address the paradox that presents itself: How can an organism of such limited hardiness and growth capabilities be responsible for an ever‐increasing level of human foodborne disease?