bluuebunny/crossref_metadata_2025 huggingface dataset:
SHELF‐LIFE OF VACUUM‐PACKAGED EVISCERATED BROILER CARCASSES UNDER SIMULATED MARKET STORAGE CONDITIONS
Authors: SAWAYA W.N. , ABU‐RUWAIDA A.S. , HUSSAIN A.J. , KHALAFAWI M.S. , DASHTI B.H.
Published: April 2007

The effects of vacuum‐packaging on the shelf‐life of eviscerated broiler carcasses, under conditions simulating market storage (4, 7 and 9C) in the State of Kuwait were studied. Vacuum‐packaging increased the shelf‐life of the carcasses by 7–8, 6 and 4 days beyond that of the conventionally‐packaged carcasses, when stored at 4, 7 and 9C, respectively. The growth of the Enterobacteriaceae was lowest in carcasses stored at 4C, irrespective of the packaging type. Of the Enterobacteriaceae, the coliforms were the predominant microorganisms (∼ 80%), whereas Salmonella accounted for up to 15%. Lactobacillus were the predominant spoilage microorganisms in the vacuum‐packaged carcasses, whereas Pseudomonas predominated in the conventionally‐packaged ones. Vacuum‐packaging can be recommended for improvement of the keeping quality of eviscerated broiler carcasses, but it should also be associated with strict procedures for controlling the handling and storage temperatures throughout the overall distribution system.
MICROBIOLOGICAL QUALITY OF CEBRERO CHEESE FROM NORTHWEST SPAIN
Authors: QUINTO E. , FRANCO C. , RODRIGUEZ‐OTERO J.L. , FENTE C. , CEPEDA A.
Published: April 2007

Cebrero cheese is traditionally manufactured from raw cow's milk in the Cebrero mountains of Galicia (NW Spain). We report determinations of pH and aw, and counts of total aerobic bacteria, psychrotrophs, Enterobacteriaceae, Escherichia coli, coagulase‐positive Staphylococcus aureus, Listeria, molds and yeasts, in 49 samples. E. coli count exceeded the level permitted by Spanish legislation in 51% of samples. S. aureus count exceeded the level permitted in 20% of the samples. In one sample, with pH 5.06, two species of Listeria (L. monocytogenes and L. seeligeri) were detected. Although the pH of this cheese is fairly low, it does not appear to be sufficient to prevent the occurrence of certain pathogenic microorganisms.
REMOVAL OF SALMONELLA TYPHIMURIUM ATTACHED TO CHICKEN SKIN BY RINSING WITH TRISODIUM PHOSPHATE SOLUTION: SCANNING ELECTRON MICROSCOPIC EXAMINATION
Authors: KIM JEONG‐WEON , SLAVIK MIKE F. , BENDER FREDRIC G.
Published: April 2007

The effect of trisodium phosphate (TSP) on Salmonella typhimurium attached to chicken skin was investigated by using scanning electron microscopy (SEM). Chicken drumsticks were inoculated with Salmonella typhimurium (2 × 108 CFU/mL) for 30 min. Both inoculated and non‐inoculated drumsticks were rinsed with 10% TSP solution at 10 or 50C for 15 s, and skin pieces were cut and fixed for SEM examination. For inoculated skins, a significant difference was noticed between TSP‐rinsed and control skins (water‐rinsed) at both temperatures. While control skins were covered with salmonellae (4 × 105∼ 1 × 106 CFU/cm2) and miscellaneous debris, TSP‐rinsed skins, either at 10 or 50C, showed clean skin surfaces (<8×103 CFU/cm2). For non‐inoculated skins, it was difficult to see the difference in the number of attached bacteria due to their low numbers, however, water‐rinsed skins still showed the debris on the surface. Above observations suggest that one of the major mechanisms of TSP on salmonellae reduction is detachment of contaminants from the skin surface.
INCIDENCE OF LISTERIA SPECIES IN INDIAN SEAFOODS AND MEAT
Authors: KAMAT A.S. , NAIR P.M.
Published: April 2007

Thirty eight samples of fresh, frozen and dry seafoods and 27 samples of fresh and cold stored meat and meat products obtained from retail shops were examined for the presence of Listeria spp. Direct plating of the sample homogenate on Listeria Selective Agar (LSA) was compared with the two step enrichment method devised by Hao et al. for detecting Listeria spp. in vegetables. We report that modification of this methodology involving cold enrichment for 48 h in Brain Heart Infusion (BHI) at 10C followed by enrichment at 37C in Listeria enrichment broth (LE) resulted the enumeration of a large population of Listeria from flesh foods. Listeria isolates from fish and meat were identified by employing the cultural methods given in modified version of the Bacteriological Analytical Manual (Lovett and Hitchins 1988). Listeria spp. from seafoods were identified, with the order of predominance as L. grayi, L. innocua, L. murrayi, L. seeligeri. Samples of meat and their products were found to be contaminated mainly with L. innocua and L. murrayi. In contrast, screening of an independent batch of 20 fish and meat samples by adopting the PHLS (UK) method revealed predominance of L. grayi and L. seeligeri in fish and presence of additional species like L. seeligeri, L. ivanovii and L. welshimeri in meat products. None of the methods however could detect incidence of L. monocytogenes in any of the samples tested from local market in Bombay.
THE EFFECT OF MONO AND POLYGLYCEROL LAURATE ON SPOILAGE AND PATHOGENIC BACTERIA ASSOCIATED WITH FOODS
Authors: RAZAVI‐ROHANI S.M. , GRIFFITHS M.W.
Published: April 2007

The antibacterial activity of monolaurin and triglycerol 1,2 laurate alone and combined with three different chelating agents, at different pH (7, 6, 5.5 and 5), different NaCl concentrations (0.5 to 7%) and various combinations of pH and NaCl concentrations was investigated. The activity of these agents against 16 bacteria (7 Gram‐positive and 9 Gram‐negative) was studied using the spiral gradient end point test to determine the minimum inhibitory concentration (MIC).

Monolaurin was effective against all the Gram‐positive bacteria studied, but was only effective against the Gram‐negative bacteria in the presence of EDTA. The inhibition was greatest at low pH and high NaCl concentrations. Concern has been expressed about the use of monolaurin in foods because of its poor solubility. Polyglycerol esters are more soluble and antimicrobial activity of these compounds has been observed. Triglycerol 1,2 laurate exerted some inhibitory effects, but was not as inhibitory as monolaurin even in the presence of the chelating agent and under conditions of low pH and high NaCl levels. Other chelators investigated (monoglyceride citrate and sodium citrate) did not promote the inhibitory effect of monolaurin.
OUTGROWTH OF CLOSTRIDIUM PERFRINGENS SPORES IN COOK‐IN‐BAG BEEF PRODUCTS1
Authors: JUNEJA VIJAY K. , MAJKA WENDY M.
Published: April 2007

Clostridium perfringens growth from a spore inoculum was investigated in vacuum‐packaged, cook‐in‐bag ground beef that included 0.3% (w/w) sodium pyrophosphate, pH 5.5 or 7.0, and salt (sodium chloride) at 0 or 3% (w/w). The packages were processed to an internal temperature of 71.1C, ice chilled and stored at various temperatures. The total C. perfringens population was determined by plating diluted samples on tryptose‐sulfite‐cycloserine agar followed by anaerobic incubation for 48 h at 37C. At 28C, a combination of 3% salt and pH 5.5 was effective in delaying growth for 24 h. At 15C, growth occurred within 6 days in samples with pH 7.0, but was delayed until day 8 in the presence of 3% salt at pH 7.0. Vegetative cells were not observed even after 21 days 21 of storage at 15C in the presence 3% salt at pH 5.5. C. perfringens growth was not observed at 4C regardless of pH or salt levels. The D‐values ranged from 23.33 min (3% salt, pH 7.0) to 13.99 min (3% salt, pH 5.5). Cyclic and static temperature abuse of refrigerated products for 12–15 h did not permit C. perfringens growth. However, temperature abuse of cook‐in‐bag beef products for periods longer than 15 h in the absence of salt led to growth of C. perfringens from a spore inoculum.
INFLUENCE OF MODIFIED ATMOSPHERE PACKAGING ON SHELF‐LIFE OF CHICKEN CARCASSES UNDER REFRIGERATED STORAGE CONDITIONS
Authors: SAWAYA W.N. , ELNAWAWY A.S. , ABU‐RUWAIDA A.S. , KHALAFAWI S. , DASHTI B.
Published: April 2007

The effect of modified atmosphere packaging (MAP) (70% CO2/30% N2; 30% CO2/70% N2) on the shelf‐life of fresh chicken carcasses stored at 2, 4, 7 and 9C was investigated. The shelf‐lives of MAP carcasses (70% CO2/30%N2) stored at 2, 4, 7 and 9C were 25, 21, 12 and 8 days, respectively compared with 7 days for air‐packaged ones stored at 4C; the shelf‐life of MAP carcasses (30% CO2/70%N2) stored at the same temperatures were 20, 15, 8 and 8 days, respectively. The inhibitory effect of MAP on the growth of Enterobacteriaceae and on the production of spoilage metabolites, such as free fatty acids and extract release volume, was negligible at higher temperatures (7 and 9C) and more pronounced at lower temperatures (2 and 4C), especially at higher concentrations of CO2 (70% CO2/30% N2). The occurrence and growth of organisms such as Escherichia coli, coliforms, Staphylococcus aureus, Salmonella and Campylobacter in carcasses stored at different temperatures were also documented.
USE OF IRRADIATION TO KILL ENTERIC PATHOGENS ON MEAT AND POULTRY1
Authors: THAYER D.W.
Published: April 2007

Ionizing radiation can be an effective step in a HACCP program to kill enteric pathogens associated with meat and poultry products. The populations of most common enteric pathogens such as Campylobacter jejuni, Escherichia coli O157:H7, Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, and Aeromonas hydrophila can be significantly decreased or eliminated by low‐dose (< 3.0 kGy) treatments with ionizing radiation. Only the enteric viruses and the endospores of the genera Clostridium and Bacillus are highly resistant to ionizing radiation, and even these are affected to some degree. Temperature effects must be carefully considered, as reduced irradiation temperatures not only result in fewer adverse changes in the sensorial properties of meat and poultry products, but they also may demand that greater radiation doses be used to inactivate the foodborne pathogen. Equations have been developed that predict the effects of low‐dose ionizing radiation treatments on several enteric pathogens associated with meat and poultry. In some cases substrate‐specific differences in radiation resistance have been found. Irradiation in combination with vacuum packaging or modified‐atmosphere packaging has increased both safety and shelf‐life for some types of refrigerated products. High‐dose irradiation treatments of enzyme‐inactivated meat or poultry products in vacuo at subfreezing temperatures can be used to prepare sterile, shelf‐stable products with excellent sensorial properties. Such products have been used extensively by military organizations, NASA during space flights, yachtsman, and hospitals. Contemporary research will be reviewed.
IMPACT OF TRANSPORT AND RELATED STRESSES ON THE INCIDENCE AND EXTENT OF HUMAN PATHOGENS IN PIGMEAT AND POULTRY
Authors: MULDER R.W.A.W.
Published: April 2007

Meat products are very important sources of protein in the human diet. The contamination of these products with pathogenic microorganisms, such as Salmonella and Campylobacter, make both production and consumption of them a precarious proposition. Several methods can decrease the level of contamination with these pathogenic microorganisms. However, there are still situations of high microbial load which cannot be explained and are often attributed to stress. This paper describes the effect of transport, husbandry and nutrition practices on contamination of slaughtered products. Examples of the stress occurring during fattening, catching and loading, transport and conditioning at the processing plant, are given.
INDIVIDUAL AND COMBINED LISTERICIDAL EFFECTS OF SODIUM LACTATE, POTASSIUM SORBATE, NISIN AND CURING SALTS AT REFRIGERATION TEMPERATURE
Authors: BUNCIC S. , FITZGERALD C.M. , BELL R.G. , HUDSON J.A.
Published: April 2007

The individual and combined antilisterial activity of the preservatives sodium lactate (4%), potassium sorbate (0.3%) and nisin (400 IU/ml), in either the presence or absence of the curing salts nitrite (125 ppm) and polyphosphate (0.5%), was assessed in buffered BHI broth (pH 5.5) during incubation at 4C. A cocktail of the strain Listeria monocytogenes NCTC 7973 and two food derived strains was used as the inoculum in challenge studies. In the absence of the preservatives, L. monocytogenes grew in the presence of polyphosphate but not in the presence of nitrite or a combination of nitrite and polyphosphate. The antilisterial action of nitrite was predominantly bacteriostatic in nature. Lactate acting alone, or in the presence of curing salts, produced a bacteriostatic effect. Sorbate acting alone had a bacteriostatic effect. Sorbate acting in the presence of nitrite or nitrite and polyphosphate produced a marked listericidal effect, reducing the population by 6.7 logs and 5.4 logs, respectively. Nisin acting alone produced an almost immediate 90% listericidal response (1 log population decrease), but initial numbers were restored within 14 days by regrowth. Regrowth was eliminated when nisin was used in combination with lactate, nitrite or nitrite and polyphosphate. The combination of lactate and sorbate offered no advantage over the use of sorbate alone. Sorbate and nisin acting in combination produced an enhanced listericidal effect, which was also seen in the presence of curing salts, but was delayed. No listericidal advantage over sorbate‐nisin combination was achieved through the use of the lactate‐sorbate‐nisin combination. The combined use of sorbate and nisin offers promise as a means of eliminating L. monocytogenes from low pH cured meat products. The efficacy of this preservative combination remains to be evaluated in a meat system before its practical application can be considered.
REDUCTION OF LISTERIA MONOCYTOGENES, ESCHERICHIA COLI O157:H7 AND SALMONELLA TYPHIMURIUM DURING STORAGE ON BEEF SANITIZED WITH FUMARIC, ACETIC, AND LACTIC ACIDS1
Authors: PODOLAK R.K. , ZAYAS J.F. , KASTNER C.L. , FUNG D.Y.C.
Published: April 2007

Cylindrical samples of beef semitendinosus muscle were dipped into an inoculum of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium. After air drying for 10 min, samples were sanitized by dipping in fumaric acid (1.0 or 1.5%), lactic acid (1%) or acetic acid (1.0%) solutions for 15 or 30 s at 55C. The 1.5% fumaric acid was most inhibitory against L. monocytogenes, resulting in inactivation of this pathogen after 7 days of storage. Samples treated with 1.0% and 1.5% fumaric acid solutions for 30 sec gave 2.54 and 1.51 log10 reductions, respectively, in S. typhimurium population compared to nontreated samples. The 1.5% fumaric acid treatments for 30 s exerted the maximum inhibition of E. coli O157:7. Acetic and lactic acid treatments were significantly less effective in reducing populations of the tested pathogens than fumaric acid treatments. As the sanitizing time in acid solutions increased from 15 to 30 s, the numbers of surviving organisms were reduced significantly.
GROWTH/SURVIVAL OF NATURAL FLORA AND LISTERIA MONOCYTOGENES ON REFRIGERATED UNCOOKED PORK AND TURKEY PACKAGED UNDER MODIFIED ATMOSPHERES
Authors: MANO S.B. , DE FERNANDO G.D. GARCIA , LOPEZ‐GALVEZ D. , SELGAS M.D. , GARCIA M.L. , CAMBERO M.I. , ORDOÑEZ J.A.
Published: April 2007

Listeria monocytogenes was inoculated onto fresh pork and turkey slices. Inoculated and control samples were packaged under modified atmospheres (100% N2, and 20%/80% and 40%/60% CO2O2) or air in plastic bags of low gas permeability. Samples were stored at 1 and 7C. Samples stored in air showed a similar microbiological pattern to that usually observed in fresh meat stored aerobically. Packaging under modified atmospheres extended the meat shelf‐life. Bacterial growth was strongly inhibited at 1C, particularly in samples stored under CO2/O2 enriched atmospheres. Temperature and pH were critical factors for L. monocytogenes growth. This pathogen grew only on pork (initial pH 5.3) packaged in air and stored at 7C. No L. monocytogenes growth was observed at 1C in any atmosphere assayed. However, growth on turkey (initial pH 6.0) was marked at 7C in all atmospheres tested, while at 1C, this bacterium grew weakly only on samples stored in air.
INFLUENCE OF FAT CONTENT AND PRESERVATIVES ON THE BEHAVIOR OF LISTERIA MONOCYTOGENES IN BEAKER SAUSAGE
Authors: HU AMY C. , SHELEF LEORA A.
Published: April 2007

Behavior of Listeria monocytogenes Scott A in pork liver sausage containing 22–67% fat, and antilisterial activities of sodium lactate, sorbic acid, potassium sorbate and sodium propionate were studied during storage at 4C and 10C. Commercial pork liver sausage batter (22% fat), alone and with additions of lard (15, 30, and 45% by weight) were tested. Concentrations of 1.8% sodium lactate, 0.1% sorbate as the acid or the potassium salt, and 0.2% sodium propionate were tested in heat sterilized sausage inoculated with a 24 h culture of the organism (104 CFU/g). Fat content alone caused small reductions in cell numbers by the end of the storage periods: from log CFU/g of 9.9 to 9.4 after 14 days at 10C, and from 7.3 to 6.5 after 50 days at 4C in the basic sausage formulation and with 45% added fat, respectively. The inhibitory activities of lactate and propionate increased with increase in fat content, and were more pronounced at 4C, where the effects were listericidal. Inhibition by sorbic acid was least influenced by the fat content, and the potassium salt was less antilisterial than the acid.
INHIBITION OF SURFACE GROWTH OF TOXIGENIC AND NONTOXIGENIC ASPERGILLI AND PENICILLIA BY EUGENOL, ISOEUGENOL AND MONOLAURIN
Authors: MANSOUR NADA , YOUSEF AHMED E. , KIM JIN‐GAB
Published: April 2007

Sabouraud dextrose agar, containing up to 300 ppm of eugenol, isoeugenol or monolaurin, was prepared. Eight strains of mycotoxin and non‐mycotoxin‐producing Aspergillus spp. and Penicillium spp. were tested. Spore suspensions were spotted in the center of agar plates and the linear (radial) growth rate was measured during incubation. All agents inhibited mold growth, but isoeugenol and eugenol were more effective than monolaurin. The average decreases in linear growth rate in the presence of eugenol, isoeugenol and monolaurin were 56, 43 and 11% at 100 ppm and 81, 85 and 15% at 200 ppm, respectively. At 300 ppm eugenol and isoeugenol, all fungi were inhibited completely; however, monolaurin (up to 2000 ppm) did not prevent mold growth. Except for P. viridicatum NRRL 6062, the molds tested did not vary significantly (at p=0.05) in degree of inhibition by any particular antifungal agent.

A. parasiticus was grown in a yeast extract dextrose broth containing 100 ppm of the antifungal agents. Decreases in mycelial dry weight in the presence of eugenol, isoeugenol and monolaurin were 5.3, and 7.9, 10.5%, respectively. The corresponding reductions in aflatoxin B1 synthesized were 58, 57 and 25%. In conclusion, eugenol and isoeugenol have strong antifungal properties which are best manifested when the surface growth of molds on solid media is monitored.
GROWTH OF ESCHERICHIA COLI O157:H7 IN THE PRESENCE OF PSEUDOMONAS FLUORESCENS IN SKIMMED MILK AT 7 OR 25C
Authors: QUINTO E.J. , FRANCO C.M. , FENTE C.A. , VAZQUEZ B.I. , CEPEDA A.
Published: April 2007

Escherichia coli O157:H7 STCC 4076, E. coli O157:H7 STCC 4267 and E. coli STCC 515 were cultured alone or in combination with Pseudomonas fluorescens STCC 378 at 7C or 25C in 10% reconstituted skimmed milk. Culture pH and bacterial population densities were monitored over 40 days. Both E. coli O157:H7 strains grew well after 40 days of incubation at 7C with final pH values between 4.86–4.53. At 25C, both E. coli O157:H7 strains grew during 20 days with final pH values of 4.00–4.14. The pH of the different cultures of this study decreased more at 25C than at 7C. The results suggest that P. fluorescens may inhibit the growth of the other bacteria present in milk at 7C, but this inhibition is weak. In contrast, the growth of E. coli O157:H7 strains in the presence of P. fluorescens appears to be slightly enhanced during most of the incubation period at 25C.
OCCURRENCE OF TYRAMINE PRODUCING MICROORGANISMS IN “SALCHICHON” AND TYRAMINE PRODUCTION IN SAUSAGES INOCULATED WITH A TYRAMINE PRODUCING STRAIN OF LACTOBACILLUS BREVIS
Authors: ROIG‐SAGUÉS A.X. , HERNÁNDEZ‐HERRERO M. , RODRÍGUEZ‐JEREZ J.J. , LÓPEZ‐SABATER E.I. , MORA‐VENTURA M.T.
Published: April 2007

Tyrosine decarboxylase activity of different isolates obtained from 20 samples of raw (before the ripening process) and 10 of ripened “salchichón”, a cured sausage produced in Spain, was evaluated. Although 33% of the isolates obtained from raw sausages showed a positive response in the decarboxylation medium described by Joosten and Northolt (JNM), only 8.4% were subsequently confirmed as tyramine formers by thin layer chromatography (TLC). Pseudomonads and enterobacteria showed the highest percentage of positive isolates in JNM, but none was confirmed by TLC. In contrast, 100% of positive enterococci were confirmed. Most of confirmed isolates obtained from raw sausages were identified as Enterococcus faecalis while Enterococcus faecium and Lactobacillus curvatus showed the highest prevalence in ripened sausages. Inoculation with a tyramine forming strain of Lactobacillus brevis, isolated from raw sausage, did not increase the amounts of tyramine formed during the production process of the sausage.
EFFECT OF TRISODIUM PHOSPHATE ON LISTERIA MONOCYTOGENES ATTACHED TO RAINBOW TROUT (ONCORHYNCHUS MYKISS) AND SHRIMP (PENAEUS SPP.) DURING REFRIGERATED STORAGE
Authors: MU DONGMIN , HUANG YAO‐WEN , GATES KEITH W. , WU WEN‐HSIN
Published: April 2007

The potential of using trisodium phosphate (TSP) to reduce bacterial populations in fresh fishery products was explored since TSP has recently been approved by USDA for its usage in poultry processing to eliminate Salmonella contamination. Fresh headed shrimp and rainbow trout fillets were inoculated with L. monocytogenes before dipped in tap water, 10% TSP, or 20% TSP solutions and overwrap‐packaged. Surface pH values, psychrotrophic plate counts, and L. monocytogenes counts of inoculated shrimp and trout fillets were determined after 0, 3, 6, and 9 days of storage at 4C. The TSP treatment resulted in relatively high residual surface pH values (11–12) initially in both shrimp and trout fillets. Compared to tap water dipping, TSP treatment did not significantly reduce psychrotrophic or Listeria populations in shrimp. However, the 20% TSP treatment significantly (p < 0.05) lowered 0‐day psychrotrophic and L. monocytogenes counts of trout fillets and remained effective for 6 days during storage at 4C.
INHIBITION OF STAPHYLOCOCCUS AUREUS AND BACILLUS CEREUS ON A VEGETARIAN FOOD TREATED WITH NISIN COMBINED WITH EITHER POTASSIUM SORBATE OR SODIUM BENZOATE
Authors: FANG TONY J. , CHEN CHUN‐YUAN , CHEN HELEN H.L.
Published: April 2007

Various amounts of nisin (0, 103 and 5 × 103 IU/g) in combination with either potassium sorbate (0, 2, and 3%) or sodium benzoate (0, 0.06 and 0.12%) were tested for effectiveness in inhibiting growth of Staphylococcus aureus C10 and Bacillus cereus B7 inoculated on a vegetarian food. The strains used were isolated from vegetarian foods obtained commercially in Taiwan, and the test food, spice and dried bean curd, was selected for the study based on ability to support the growth of these organisms. After treatment with a preservative combination, the surfaces of sterilized food samples were inoculated, samples were stored in vacuum or nonvacuum packages at either 4C or 30C, and at appropriate times, tested for microbial growth. Growth of both isolates was unaffected by vacuum‐packaging treatment; however, a bacteriostatic effect was found at 4C. Data indicated that during the 14‐day storage at 4C, vacuum‐packaged samples treated with 5 × 103 IU/g nisin and 0.12% sodium benzoate significantly (p < 0.05) decreased the counts of S. aureus C10 and B. cereus B7 by 2.61 and 3.02 log10 CFU/g, respectively. In the vacuum‐packaged samples treated with 5 × 103 IU/g nisin and 3% potassium sorbate, counts for C10 and B7 were decreased by 2.35 and 2.64 log10 CFU/g, respectively. Thus, the combined treatment extended the shelf‐life of the vegetarian food.
MICROBIOLOGICAL STATUS OF EGYPTIAN SALTED MEAT (BASTERMA) AND FRESH SAUSAGE
Authors: EL‐KHATEIB TALAAT
Published: April 2007

The microbiological quality of 125 samples of the most popular Egyptian meat products (75 Egyptian fresh sausage “EPS” and 50 basterma) was determined. The aerobic plate count (APC) and Lactobacillaceae count of basterma ranged from 1 × 104 to 9 × 106 CFU/g, respectively. Enterobacteriaceae, mold and yeast counts for basterma were similar (<1 × 102 CFU/g). Artificially contaminated slices of meat and garlic paste of basterma showed that the paste inhibited growth of Salmonella typhimurium. APC and Enterobacteriaceae counts of EFS ranged from 1.1 × 104 to 1 × 108 and from 1 × 102 to 1 × 107 CFU/g, respectively. Nearly 26% and 29% of EFS were positive for Clostridium perfringens and coagulase‐positive Staphylococcus aureus, respectively. Salmonella could not be detected in any examined samples. Bacteriologically, EFS might pose a potential health hazard, making it imperative to institute sanitary measures during its production and sale.; Accepted for Publication July 2, 1997
EVALUATION OF PCR AND DNA HYBRIDIZATION PROTOCOLS FOR DETECTION OF VIABLE ENTEROTOXIGENIC CLOSTRIDIUM PERFRINGENS IN IRRADIATED BEEF
Authors: BAEZ LUIS A. , JUNEJA VIJAY K. , THAYER DONALD W. , SACKITEY SOLOMON
Published: April 2007

The sensitivity of DNA hybridization and polymerase chain reaction (PCR), was evaluated in irradiated cooked and raw beef samples. A membrane‐based colony hybridization assay and a PCR protocol, both with specificity for the enterotoxin A gene of Clostridium perfringens, were compared with viable plate counts. The results of the colony hybridization procedure were in agreement with viable plate counts for detection and enumeration of enterotoxigenic C. perfringens. The PCR procedure combined a 4 h enrichment followed by a nucleic acid extraction step and assessed the amplification of 183 and 750 base pair enterotoxin gene targets. Detection of C. perfringens by PCR did not show a reliable correlation with viable plate counts or the colony hybridization assay. C. perfringens killed by irradiation were not detected by the plate count or colony hybridization methods; however, killed cells were detected with the PCR technique. By relying on the growth of viable cells for detection and/or enumeration, the colony hybridization and plate count methods provided a direct correlation with the presence of viable bacteria.; Accepted for Publication August 6, 1997
EFFECT OF MICROWAVE HEATING ON SURVIVAL OF SALMONELLA TYPHIMURIUM IN ARTIFICIALLY CONTAMINATED READY‐TO‐EAT FOODS
Authors: TASSINARI ADRIANA DOS REIS , LANDGRAF MARIZA
Published: April 2007

This research evaluated the destruction of Salmonella typhimurium during reheating of foods in two different types of microwave ovens: a conventional 750W oven and 700W oven with preset controls. The heating times in the conventional microwave oven were established as 50 s for baby food and 75 s for mashed potatoes as well as for the beef stroganoff samples, while for the preset oven those periods of time were determined by a built‐in temperature sensor. The percentage of food samples positive for S. typhimurium in conventional microwave was 47.8% while in microwave with preset controls it was 93.3%. Our results suggest that reheating contaminated foods in microwave ovens may, therefore, not be sufficient to destroy S. thyphimurium in order to assure food safety.
EFFECT OF GAMMA IRRADIATION ON THE LIPID PEROXIDATION IN CHICKEN, LAMB AND BUFFALO MEAT DURING CHILLED STORAGE
Authors: KANATT S.R. , PAUL P. , D'SOUZA S.F. , THOMAS P.
Published: April 2007

Chicken, lamb and buffalo meat were subjected to low‐dose gamma irradiation (2.5 kGy) and stored at 0–3C. Lipid peroxidation in terms of thiobarbituric acid (TBA) number and carbonyl content were monitored during storage. While irradiated meat showed slight increase in TBA number and carbonyl content on storage as compared to nonirradiated meat, this did not affect the sensory qualities of meat. Free fatty acid content decreased markedly on irradiation. Irradiated meats were microbiologically safe and sensorily acceptable up to 4 weeks in the nonfrozen state (0–3C) while nonirradiated meat had a shelf‐life of less than 2 weeks.
PASTEURIZATION OF VACUUM‐SEALED PACKAGES OF SUMMER SAUSAGE INOCULATED WITH LISTERIA MONOCYTOGENES
Authors: ROERING ANN M. , WIERZBA RACHEL K. , IHNOT ANNE M. , LUCHANSKY JOHN B.
Published: April 2007

Packages containing chubs of summer sausage were inoculated with about 108 cfu/mL of a three‐strain mixture of Listeria monocytogenes and vacuum sealed. The fate of the pathogen was then monitored after pasteurization at 150F (66C), 170F (77C), 190F (88C) and 21 OF (99C) for 0 to 240 s. Pathogen numbers were reduced by about 3 log10 cfu per gram within 30, 60, or 90s at 21 OF (99C), 190F (88C), or 170F (77C), respectively, whereas numbers were reduced by <2.0 log10 cfu per gram after 240 s of heating at 150F (66C). The calculated D values were 2.08 min at 150F (66C), 0.84 min at 170F (77C), 0.37 min at 190F (88C), and 0.28 min at 21 OF (99C). These results establish the feasibility of using pasteurization to control L. monocytogenes in packaged summer sausage.
GROWTH RESPONSE OF A SALMONELLA TYPHIMURIUM POULTRY ISOLATE TO PROPIONIC ACID UNDER AEROBIC AND ANAEROBIC CONDITIONS
Authors: KWON Y.M. , HA S.D. , RICKE S.C.
Published: April 2007

Organic acids have long been used as additives in poultry feed to reduce microbial populations, including Salmonella spp. Propionic acid addition to poultry feed has a potential role in reducing Salmonella spp. in the chicken intestine. In this study, in vitro growth response of S. typhimurium isolated from poultry to propionic acid under aerobic and anaerobic conditions was determined. When grown in tryptic soy broth (TSB) containing buffered propionic acid (BPA), the growth rate of S. typhimurium gradually decreased as the level of BPA increased and broth pH decreased. No growth was detected with BPA concentrations greater than 3% (volume/volume) of the broth. When the growth rates of S. typhimurium in aerobic and anaerobic TSB were compared at two pH levels (pH 5.0 and 7.0), the growth inhibition of S. typhimurium by propionic acid was markedly suppressed by anaerobiosis at both pHs, as indicated by significantly (p<0.05) higher half‐inhibition constants (K°). Also, the growth rates of S. typhimurium in the presence of propionic acid were dramatically reduced by the decrease in pH from 7.0 to 5.0. The results of this study indicated that the growth inhibitory effect of propionic acid against S. typhimurium strains was enhanced by pH decrease and suppressed by anaerobiosis, suggesting that the growth response of S. typhimurium to propionic acid in the chicken intestine might be affected by the environmental conditions such as pH and anaerobiosis.
FUNGAL BIOTA ISOLATED FROM SPANISH CHEESES
Authors: BARRIOS Ma J. , MEDINA L.M. , LOPEZ Ma C. , JORDANO R.
Published: April 2007

Fungal biota, with special reference to the genus Penicillium, was studied in 52 samples of commercial cheeses (10 fresh, 17 semiripened and 25 ripened) made from different types of milk (cow, ewe, goat and mixed) produced in southern Spain. In 41 of the total of cheeses analyzed (79%) molds were isolated. Penicillium was identified in 63% of the samples, Mucor spp. in 27%, Geotrichum candidum in 17% and Cladosporium herbarum in 10%; eleven other fungal genera were detected ranging from 2 to 4%. Thirty‐five species of Penicillium were analyzed with the following distribution: 7 in fresh cheese, 16 in semiripened cheese and 30 in ripened cheese. The incidence of Penicillium spp. was also greater in the cheeses with a higher degree of ripeness, i.e. 20% in fresh cheese, 71% in the semiripened and 76% in the ripened cheese.
INACTIVATION OF THE BSE AGENT
Authors: TAYLOR D. M.
Published: April 2007

Bovine spongiform encephalopathy (BSE) belongs to a distinct group of transmissible degenerative encephalopathies (TDE) that includes scrapie in sheep and Creutzfeldt‐Jakob disease (CJD) of humans. These fatal neurological diseases are caused by unconventional but uncharacterized transmissible agents that have a number of unusual properties; this includes a high degree of resistance to inactivation. The only disinfectant that appears to be completely effective against high titres of TDE infectivity is sodium hypochlorite. Exposure to 1 to 2 M sodium hydroxide has a substantial but incomplete effect, as does autoclaving at temperatures between 132 and 138C for up to an hour; however, a combination of 2 M sodium hydroxide and autoclaving, even at the more modest temperature of 121C for 30 min, appears to be completely effective. With lower titres of infectivity, less rigorous regimes may be effective. For example, although most of the rendering procedures used to manufacture meat and bone meal (MBM) throughout the European Union (EU) have been found to be incapable of inactivating BSE and scrapie agents, one method which appeared to be effective with moderate titres of BSE and scrapie agent, involved exposure to steam at 133C for 20 min. This procedure is now the only one approved within the EU for the manufacture of MBM for feeding animals, excluding ruminants; however, the UK has introduced a ban on feeding MBM to any farmed species because of the occurrence of a new variant form of CJD in the UK which appears to have been caused by the BSE agent.

Although the clinical signs of scrapie in sheep are entirely attributable to neurological dysfunction, tissues such as spleen and lymph nodes are known to become infected before those of the central nervous system. In contrast, the only tissues which have been found to become infected in cattle with natural BSE are brain, spinal cord and retina. These are no longer used in animal or human foodstuff. Because scrapie agent has no known association with human disease there has been no restriction in the past on using any sheep tissues, including brain, as human food; however, it is known from experimental studies that the BSE agent can infect sheep by the oral route to cause a disease that is clinically and neurohistopathologically indistinguishable from scrapie. It is also known that the spleen becomes infected in such sheep. Sheep in the UK could theoretically have become infected with the BSE agent through the feeding of infected MBM before the feed‐ban in 1988. There are now measures in place that prevent the head, spinal cord, and spleen of sheep being incorporated into foodstuff.
RESIDUES – A FOOD SAFETY PROBLEM?
Authors: O'KEEFFE MICHAEL , KENNEDY ORLA
Published: April 2007

Considerable time, regulation and consumer concern is associated with the question of chemical residues in food. Potential residues in food span a broad range from natural contaminants (mycotoxins) through environmental contaminants (dioxins, PCBs), agrochemicals (nitrates, pesticides), veterinary drugs (anthelmintics, antibiotics), prohibited substances (hormonal growth promoters), chemicals arising in processing (nitrosamines), packaging components (plasticisers) to contaminants arising in domestic food preparation (heavy metals). The occurrence or avoidance of these chemicals as residues in food is to a greater or lesser extent under the control of the food producer, processor and consumer in the activities of growing/producing, treating, storing, processing, packaging and cooking. The fundamental question is to what extent do or can residues in food constitute a food safety hazard for the consumer. Many of these substances are regulated as to their use and as to their acceptable levels in food while others, by their nature, arise as more random occurrences and, as such, are less prone to regulation. Of particular concern to the producer, processor and retailer of food is what steps may be taken to ensure that the food supply is safe. Best practice in plant and animal husbandry by the producer, in sourcing of material and in control of food manufacturing by the processor, and in sourcing of food products by the retailer combine to assure the safety of food to the consumer. This paper describes the various classes of chemicals which can arise as residues in food, particularly agrochemicals and veterinary drugs, the usage patterns which decrease/increase the likelihood of the occurrence of residues at unacceptable levels, how and in what form(s) residues can occur in foods, and the contribution of food processing to a reduction or otherwise of residue levels in food consumed. Consideration will be given, also, to quantifying the risk posed by chemical residues in food and to a study of the results from a Residue Database and from residue monitoring/surveillance as an indicator of risk to the consumer.
RECOVERY AND GROWTH OF SOME FOOD‐BORNE PATHOGENS IN IRRADIATED LOW AND HIGH FAT FISH DURING STORAGE AT 2‐4C
Authors: KAMAT ANU , THOMAS PAUL
Published: April 2007

This report presents results of the investigations carried out to understand the role of fat levels in fish on postirradiation recovery/survival and growth of four pathogens generally encountered in seafoods. Fish of low [golden anchoy, (Coillia dussumierij, 0.39%] as well as high fat [Indian sardine, (Sardinella longiceps), 7.1 %] content (with endogenous biota were inoculated separately with cells of Listeria monocytogenes 036, Yersinia enterocolitica 5692, Bacillus cereus and Salmonella typhimurium; and irradiated at doses of 1 and 3 kGy. The number of viable organisms for each was monitored for two weeks at 2‐4C on appropriate selective media. The four pathogens studied exhibited variation in their ability to recover from radiation damage as evidenced in terms of lag period; but their recovery and subsequent growth was not influenced by the fat levels offish. No increased growth of any of the pathogens tested was evidenced in irradiated fish, when compared with nonirradiated one.
ANTIFUNGAL EFFECTS OF SORBIC ACID AND PROPIONIC ACID AT DIFFERENT pH AND NaCl CONDITIONS
Authors: RAZAVI‐ROHANI S.M. , GRIFFITHS M.W.
Published: April 2007

The effect of pH (7, 5.6, 3.5), NaCl concentration (3 to 20% w/v) and EDTA on the antifungal activity of sorbic acid and propionic acid (Ca salt) against Candida spp., Sporothrix sp., Fusarium sp., Penicillium spp., Paecilomyces sp. and Aspergillus spp. was investigated by the Spiral Gradient End Point Test. Sorbic acid was active against most yeasts and molds, and in the presence of EDTA, which enhanced the effect of sorbic acid, all the organisms tested were inhibited. Sorbic acid was most effective at low pH. The inhibitory effect of sorbic acid increased with increasing NaCl concentration for all test organisms. Propionic acid was not as active as sorbic acid, but when combined with EDTA the inhibition was improved for some of the molds tested. Increasing or decreasing the pH did not change the antifungal activity of propionic acid. Synergistic effects of NaCl occurred at concentrations higher than 10%, but when EDTA was added, the inhibition was seen even at the lower NaCl concentrations.
PREDICTIVE MODEL FOR THE COMBINED EFFECT OF TEMPERATURE, pH, SODIUM CHLORIDE, AND SODIUM PYROPHOSPHATE ON THE HEAT RESISTANCE OF ESCHERICHIA COLI O157:H71
Authors: JUNEJA VIJAY K. , MARMER BENNE S. , EBLEN BRIAN S.
Published: April 2007

The effects and interactions of heating temperature (5–62.5C), pH (4 – 8), NaCl (0 – 6%, w/v), and sodium pyrophosphate (0 – 0.3%, w/v) on the heat resistance of a four strain mixture of Escherichia coli O157:H7 in beef gravy were examined. Thermal death times were determined using a submerged coil heating apparatus. The recovery medium was plate count agar supplemented with 1% sodium pyruvate. Decimal reduction times (D‐values) were calculated by fitting a survival model to the data with a curve fitting program. The D‐values were analyzed by second order response surface regression for temperature, pH, NaCl and sodium pyrophosphate levels. The four variables interacted to affect the inactivation of the pathogen. Thermal resistance of E. coli O157:H7 can be lowered by combining these intrinsic factors. A mathematical model describing the combined effect of temperature, pH, NaCl and sodium pyrophosphate levels on the thermal inactivation of E. coli O157:H7 was developed. The model can predict D‐values for any combinations of temperature, pH, NaCl and sodium pyrophosphate that are within the range of those tested.
EFFECT OF GAMMA IRRADIATION ON AFLATOXIN B1 PRODUCTION BY ASPERGILLUS FLAVUS IN GROUND BEEF STORED AT 5C
Authors: YOUSSEF BOTHAINA M. , MAHROUS SOUZAN R. , AZIZ NAGY H.
Published: April 2007

The effect of γ‐irradiation for controlling the production of aflatoxin B1 by Aspergillus flavus in ground beef stored at 5C for 2 weeks was investigated. Aspergillus, Penicillium, Cladosporium, Mucor, Scopulariopsis, Candida and Rhodotorula were the most common fungal genera contaminating ground beef. A. flavus and A. niger were the most common Aspergillus spp. Aspergillus flavus isolates were able to produce aflatoxin B1 in ground beef. Only 3 (20%) samples of ground beef were contaminated with aflatoxin B1 (25–45 μg/Kg). Gamma irradiation dose levels resulted in an immediate reduction in the total numbers of A. flavus. No growth or aflatoxin B1 production occurred at 1.50 kGy during storage.
PROTEIN PROFILE CHANGES IN ACID ADAPTED LISTERIA MONOCYTOGENES EXHIBITING CROSS‐PROTECTION AGAINST AN ACTIVATED LACTOPEROXIDASE SYSTEM IN TRYPTIC SOY BROTH
Authors: RAVISHANKAR SADHANA , HARRISON MARK A. , WICKER LOUISE
Published: April 2007

Foodborne pathogens often tolerate and survive environmental stress conditions including extreme acidity to varying degrees. One possible reason for this survival may be the production of protective stress proteins during acid shock (ASR) and/or tolerance (ATR) responses. The ASR and ATR of Listeria monocytogenes strains V7, V37 and CA in tryptic soy broth without dextrose acidified with lactic acid were studied. Possible cross‐protection of acid adapted cells against an activated lactoperoxidase system was also determined. The strains were either directly challenged at pH 4.0 and 3.5 to study their ASR or initially adapted at pH 5.5 for the equivalent of 1 generation before challenging at pH 4.0 and 3.5 to study their ATR. Adapted and nonadapted cells were challenged at pH 4.5 with or without an activated lactoperoxidase system. In all cases viability was determined by enumeration over a period of 24 or 48 h after challenge and the production of stress proteins analyzed by 2‐dimensional gel electrophoresis. While there were some differences in the survival responses for each strain, the acid adapted cells of each strain survived to a greater degree than nonadapted cells at both pH 4.0 (at least 10 fold at 24 h) and pH 3.5 (at least 1000 fold at 6 h) but not at pH 4.5. The acid adapted cells exposed to the lactoperoxidase system survived better (at least 5‐fold) than their nonadapted counterparts for all 3 strains at 24 and 48 h. The 2‐dimensional gel analysis for all 3 strains showed that the adapted and nonadapted cells underwent a change in their physiology, (at pH 4.0 compared to the control at pH 7.0; at pH 4.5 with the addition of lactoperoxidase system components) in that there was induction as well as repression of several proteins.
ENUMERATION OF AEROMONAS FOR VERIFICATION OF THE HYGIENIC ADEQUACY OF SWINE CARCASS DRESSING PROCESSES1
Authors: YU SHEW‐LING , PALUMBO SAMUEL A.
Published: April 2007

Populations of Aeromonas spp. and aerobic bacteria from dehairing equipment and from carcasses passing through different processing steps in a swine slaughtering plant were evaluated to identify the hygienic risks of each operation. Sponge samples were taken from the scraper flails in dehairing machines and the surface of the shackling table at pre‐ and post‐operation times, with 20 samples from each location being collected at each time. Increased post‐operation levels of Aeromonas spp. indicated a buildup and possible spread of these bacteria to carcasses. The belly skins of 40 dehaired carcasses were each sampled at five points along the process line which were after the shackling, after the final singeing, after the final polishing, after the final wash and after chilling. The levels of microbial contaminants on carcasses varied at each processing step. The heaviest contamination of carcasses with Aeromonas (1.88 log CFU/cm2) and aerobic bacteria (2.66 log CFU/cm2) occurred after shackling. Counts were reduced at other steps as a result of singeing, washing and chilling operations. However, singed carcasses were recontaminated with Aeromonas and aerobic bacteria during the polishing operation. Aeromonas hydrophila were the most prominent motile aeromonads (74.1%) recovered at the plant. The findings for Aeromonas spp. were similar to those for aerobic bacteria (r2= 0.9995) which suggested that Aeromonas spp. are appropriate indicators for assessing carcass dressing processes.
WHIPPLE'S DISEASE: IS TROPHERYMA WHIPPELII (WHIPPLE'S BACILLUS) FOODBORNE?1
Authors: SMITH JAMES L.
Published: April 2007

Whipple's disease is a rare systemic disease with symptoms dominated by diarrhea, weight loss, arthralgia or arthritis and abdominal pain. Whipple's disease is limited to humans and the disease is caused by infection with the grampositive bacterium, Tropheryma whippelii. PCR determinations suggest that T. whippelii is an environmental actinomycete but studies on the organism have been limited due to the inability to culture the organism in vitro. Most patients are male Caucasians older than 50 years of age living in North and South America, England, continental Europe and Australia. The cellular immune system appears to control T. whippeliiand patients with cellular immune defects appear to be more susceptible to Whipple's disease. The disease affects the gastrointestinal tract, the central nervous system, cardiovascular system and musculoskeletal system; however, other organs also may be affected. Whipple's disease can be treated with antibiotics effective against gram‐positive bacteria but relapses are common. Untreated Whipple's disease is usually fatal. Although the mode of transmission of T. whippelii in humans is unclear, it possibly occurs through the fecal‐oral route and food and/or water may be the source of the organism.
ISOLATION AND CHARACTERIZATION OF BACTERIOCIN‐PRODUCING MICROORGANISMS FROM AGOS‐OS
Authors: TAN JULIE D. , GALVEZ FLOR CRISANTA F. , TOMITA FUSAO
Published: April 2007

Agos‐os, a fermented meat and sweetpotato mixture, was produced and analyzed for its microbial characteristics. pH decreased during fermentation. Mold and anaerobic bacterial counts increased while yeasts and aerobic bacterial counts decreased during the third and seventh day of fermentation. Six isolates with the widest zones of inhibition on the indicator lawn were selected for bacteriocin production. These isolates had exactly the same morphological, physiological and biochemical characteristics. The ribosomal RNA sequence was 99.5% identical with Enterococcus faecalis VRE 1492. The identification was confirmed through DNA homology test by the EMBL Genbank, Canada. This bacterium produced the L‐isomer lactic acid. The amount of bacteriocin produced by the bacterium was optimized by growing the bacterium at different growth media, initial pH and fermentation time. Maximum production of bacteriocin was achieved in MRS (De Man Rugosa and Sharpe) medium (with glucose) at pH 7.50. The crude bacteriocin inhibited the growth of gram‐positive bacteria such as Lactobacillus sake 15521 and Listeria innocua. The gram‐negative bacteria such as Escherichia coli DH 5‐alpha (with plasmid, PUC), Salmonella typhii and Staphylococcus aureus were weakly inhibited. Other microorganisms such as Lactobacillus curvatus D31685, Lactobacillus confusius M23036, Lactococcus lactis MG1363, Leuconostoc paramesenteroides S67831, Pediococcus pentosaceus M58834, Saccharomyces cerevisiae SS553 (wild type) and Escherichia coli JM109 (no plasmid) were not inhibited.