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PubMed1998

Acquisition, storage, and review of safety data from a commercial system for high temperature, short time pasteurization.

A high temperature, short time (HTST) pasteurization system was equipped with electronic sensors to determine the temperature, pressure, flow rate, and position of the flow diversion valve. A computer for data acquisition was wired to the sensors to monitor and to record processing conditions related to public health. The processing conditions were stored in safety files on the hard drive of the computer, transferred weekly to a tape drive, and stored. The processing conditions of the HTST system were monitored for 270 d to determine the accuracy and reliability of the data acquisition system. The size of the HTST safety files ranged from 6.2 to 9.1 MB when the sensors were monitored every second. The file size was reduced to < 1.8 MB when the monitoring frequency was increased to every 5 s. To determine accuracy, the temperatures recorded by the data acquisition system were compared with the temperatures recorded by an electronic recorder controller. To determine reliability, changes in the position of the flow diversion valve were examined to identify process deviations and were compared with the event marker on circular charts. The review of the data file by the actual time method was an effective alternative to the electronic recorder controller for monitoring the completeness of data in the safety files. Off-line review to determine reliability required approximately 10 min/d of records.

Animals↗

PubMed1997

First clinical experiences with a new ovine Fab Echis ocellatus snake bite antivenom in Nigeria: randomized comparative trial with Institute Pasteur Serum (Ipser) Africa antivenom.

During the past decade, effective snake antivenoms have become scarce in northern Nigeria. As a result, many patients severely envenomed by the saw-scaled or carpet viper (Echis ocellatus), which is responsible for more than 95% of the snake bites in the region, did not receive effective treatment and mortality and morbidity increased. To combat this crisis, a new monospecific ovine Fab antivenom (EchiTab) is being developed. Its theoretical advantages over conventional equine F(ab')2 antivenom are a more rapid tissue penetration and larger apparent volume of distribution (the volume of [tissue] fluid in which the the antivenom would be uniformly distributed to achieve the observed plasma concentration). In a preliminary study, two vials (20 ml; 1.0 g of protein) of EchiTab rapidly and permanently restored blood coagulability and cleared venom antigenemia in seven envenomed patients. Four experienced early reactions that responded to epinephrine. In a randomized comparative trial of one vial (10 ml; 0.5 g protein) of EchiTab or four ampules (40 ml; 2.12 g of protein) of Institute Pasteur Serum (Ipser) Africa polyspecific F(ab')2 antivenom, there were fewer reactions, but only 36% and 35% of patients, respectively, showed permanent restoration of coagulability, with the remainder requiring further doses. This suggests that 0.5 g (one vial) of EchiTab is approximately equivalent to 2.12 g (four ampules) of Ipser Africa antivenom, and that a higher initial dose will be required for most patients. Measurements of circulating venom and antivenom levels reflected the clinical events.

Adolescent↗

PubMed1996

Potential Bacillus subtilis alpha-amylase-based time-temperature integrators to evaluate pasteurization processes.

Thermal inactivation kinetics of Bacillus subtilis alpha-amylase (BSA) in different environmental conditions was studied by performing isothermal experiments. As a response property, residual enzymic activity and residual heat of enzyme deterioration were chosen. A comparison of processing values determined from the read-out of a system with actual integrated processing values revealed the potentials of these systems as time-temperature integrators to be used in the pasteurization domain (temperatures of 70 to 100 degrees C) for target attributes with z-values ranging from 6 to 12 degrees C.

Bacillus subtilis↗

PubMed1998

Survival of bacterial pathogens in pasteurized process cheese slices stored at 30 degrees C.

Six lots of commercial pasteurized process cheese slices were evaluated for the ability to support the growth of four foodborne pathogens, Listeria monocytogenes, Staphylococcus aureus, Salmonella serotypes, and Escherichia coli O157:H7, during 4 days of storage at 30 degrees C. Individual cheese slices were inoculated separately with each pathogen to yield ca. 10(3) CFU/g. Slices were packaged in sterile plastic sample bags and stored at 30 degrees C for up to 96 h. Population of Salmonella serotypes and Escherichia coli O157:H7 decreased an average of 1.3 and 2.1 log10 CFU/g, respectively, by 36 h and Salmonella serotypes decreased an additional 0.6 log10 CFU/g during the remaining 60 h. Populations of Listeria monocytogenes also decreased, although to a lesser extent, exhibiting approximately a 0.6-log10 CFU/g reduction in 96 h. Staphylococcus aureus levels remained relatively constant during the testing period, and were below levels that support detectable enterotoxin production. The process cheese slices tested allowed survival but did not support rapid growth of S. aureus, whereas populations of L. monocytogenes, E. coli O157:H7, and Salmonella serotypes decreased during the 96-h storage at 30 degrees C.

Bacteria↗

PubMed1999

Influence of guar gum on the thermal stability of Listeria innocua, Listeria monocytogenes, and gamma-glutamyl transpeptidase during high-temperature short-time pasteurization of bovine milk.

Mathematical models describing the thermal inactivation of gamma-glutamyl transpeptidase (TP) and Listeria innocua in milk during high-temperature short-time (HTST) pasteurization were validated with data from TP, L. innocua, and L. monocytogenes trials in guar gum-milk. Holding tube times were determined for turbulent flow using water, and for laminar flow using a guar gum (0.27% wt/wt)-sucrose (5.3% wt/wt)-water mixture. Inactivation of TP and L. innocua was lower in a solution of guar gum (0.25% wt/wt) in whole milk than was predicted by models derived from studies with whole milk alone. Use of laminar flow timings improved model fit but did not completely account for the observed protective effect. L. monocytogenes survival was close to that predicted by the L. innocua model, although some protection was afforded this pathogen under laminar flow. Considerable intertrial variability was noted for L. monocytogenes. Risk analysis simulations using @RISK, a Lotus 1-2-3W add-in, were used to account for intertrial variability. Simulated log10 %reductions consistently underpredicted experimental L. monocytogenes survival (fail-safe), thus the L. innocua model derived in milk is suitable for estimating L. monocytogenes survival in viscous products. Increased thermal tolerance during laminar flow may be attributed to the protective effect of stabilizer.

Animals↗

PubMed2000

Buffalo-milk enzyme levels, their sensitivity to heat inactivation, and their possible use as markers for pasteurization.

The activities and rates of inactivation of four enzymes in raw buffalo milk were measured in relation to the process of heating to determine the value of these enzymes as markers for the evaluation of milk pasteurization. The activities of the enzymes alkaline phosphatase (ALP), lactic dehydrogenase (LDH), gamma-glutamyltransferase (GGT), and aspartate aminotransferase (AST) were measured before and after heating at 50, 60, 70, and 80 degrees C for 1, 3, 5, 10, 20, and 30 min. The enzyme GGT showed the highest activity (712 +/- 601 IU/liter), followed by LDH (386 +/- 183 IU/liter), ALP (295 +/- 164 IU/liter), and AST (18 +/- 4 IU/liter). Heating the milk at 50 degrees C for 1 to 30 min resulted in no effect on the activity of any of the enzymes. At 60 degrees C, ALP showed the highest sensitivity to heat inactivation, whereas all other enzymes showed resistance. At 70 degrees C, ALP activity was abolished completely after 1 min, whereas GGT and LDH lost most activity after 10 min, and AST still maintained 50% activity even after 30 min. At 80 degrees C, the activities of LDH and GGT were lost, whereas AST still retained some of its activity. The results suggest that in addition to ALP, LDH and GGT, but not AST, are potential markers for heat denaturation in buffalo milk, with GGT having the advantage that its concentration is the highest.

Alkaline Phosphatase↗

PubMed2001

Thermal lethality of Salmonella Senftenberg and Listeria innocua in fully cooked and packaged chicken breast strips via steam pasteurization.

Fully cooked chicken breast strips were surface inoculated to contain 9 log10 (CFU/g) Salmonella Senftenberg or Listeria innocua. The inoculated products were vacuum packaged in 0.2-mm-thick barrier bags (241 by 114 mm), then steam pasteurized at 88 degrees C in a continuous process for 26 to 40 min or in a batch process for 33 to 41 min. After the treatments, the products were analyzed for the survivors of Salmonella or Listeria. The models were developed to correlate the surviving rate of Salmonella and Listeria with cooking time for both continuous and batch processes. A cooking time of 34 min was needed to achieve 7 logs of the reduction in a batch process. To achieve the same log reduction, a longer (6 min) cooking time was needed in a batch process than in a continuous process. The results from this study will be useful for processors to evaluate postcooking treatment procedures for ready-to-eat meat products.

Animals↗

PubMed2001

Thermal inactivation of stationary-phase and salt-adapted Listeria monocytogenes during postprocess pasteurization of surimi-based imitation crab meat.

The heat resistance of Listeria monocytogenes in surimi-based imitation crab meat was examined after growth to stationary phase or adaptation to 15% NaCl. An in-package pasteurization treatment at the cold spot of 71.1 degrees C for 15 s was calculated as adequate to inactivate 5 logs of L. monocytogenes (z-value of 5.8 degrees C). The heat resistance of L. monocytogenes in surimi did not increase after adaptation to salt.

Animals↗

PubMed2001

Survival of salmonellae in pasteurized, refrigerated calcium-fortified orange juice.

Studies were done to determine the survival of salmonellae in orange juice as affected by fortification with calcium. Four brands of commercially pasteurized orange juice fortified with calcium (350 mg/240-ml serving) and nonfortified juice were inoculated separately with three types of inocula: strains of Salmonella Muenchen (inoculum 1), serotypes of human and animal origin (inoculum 2), and isolates from raw produce- and juice-associated outbreaks (inoculum 3). Juice inoculated with populations of 6.6 to 7.0 log10 CFU of Salmonella per ml was held at 4 degrees C for up to 32 days. The number of cells of inoculum 1 that survived in juice fortified with calcium lactate/tricalcium phosphate (CaL/TCP) was significantly lower (P < or = 0.05) (2.80 log10 CFU/ml) than in nonfortified juice (3.50 log10 CFU/ml) after 32 days' storage. Death of salmonellae in inocula 1 and 2 was less in juice fortified with TCP (3.21 and 3.33 log10 CFU/ml, respectively) than in the nonfortified juice (3.75 and 4.15 log10 CFU/ml, respectively). During the 32-day storage period, populations in inocula 1 and 3 showed significantly less inactivation (2.62 and 3.12 log10 CFU/ml, respectively) in juice fortified with calcium citrate (CC) than in nonfortified juice (3.14 and 3.60 log10 CFU/ml, respectively). There were no significant differences in the survival of Salmonella in juice fortified with calcium citrate malate (CCM) and nonfortified juice. Polymerase chain reaction (PCR) typing of randomly selected Salmonella colonies revealed that Salmonella Heidelberg in inoculum 2 and Salmonella Baildon and Salmonella Poona in inoculum 3 were the most prevalent at the end of the 32-day storage period at 4 degrees C, suggesting that serotypes selected for use in inocula differed in tolerance to acidic environments. This study reveals that the form of calcium used to fortify orange juice may affect the survival of Salmonella.

Animals↗

PubMed2003

Thermal inactivation of Listeria monocytogenes on ready-to-eat turkey breast meat products during postcook in-package pasteurization with hot water.

The inactivation of Listeria monocytogenes during postcook in-package pasteurization was evaluated for fully cooked turkey breast meat products (4-kg packages). The products were surface-inoculated to contain 10(7) CFU of L. monocytogenes per cm2 of product surface. The inoculated products were vacuum-packaged in different thicknesses (0.08 to 0.33 mm) of packaging films and treated with hot water at 96 degrees C. After heat treatment, the products were immediately cooled in an ice water bath at 0 degrees C. The relationship between heating time and product surface temperature was determined for different thicknesses of packaging films. The effectiveness of heat treatment for inactivating the pathogen was affected by product surface roughness. About 50 min of heating time was needed to achieve a thermal kill of 7 log10 CFU/cm2 on products with surface roughness up to 15 mm in depth. The cooling time needed after a heat treatment increased with an increasing endpoint temperature of the heated product and the heat penetration depth reached in the product. The cooling time needed to cool the product from 71 degrees C to 4 degrees C was about 2.5-fold the heating time.

Animals↗

PubMed2004

Effectiveness of a laboratory-scale vertical tower static chamber steam pasteurization unit against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria innocua on prerigor beef tissue.

A laboratory-scale vertical tower steam pasteurization unit was evaluated to determine the antimicrobial effectiveness of different exposure times (0, 3, 6, 12, and 15 s) and steam chamber temperatures (82.2, 87.8, 93.3, and 98.9 degrees C) against pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua) inoculated onto prerigor beef tissue. Samples were collected and microbiologically analyzed immediately before and after steam treatment to quantify the effectiveness of each time-temperature combination. The 0-s exposure at all chamber temperatures (cold water spray only, no steam treatment) was the experimental control and provided < or = 0.3 log CFU/cm2 reductions. Chamber temperatures of 82.2 and 87.8 degrees C were ineffective (P > 0.05) at all exposure times. At 93.3 degrees C, significant reductions (> 1.0 log CFU/cm2) were observed at exposure times of > or = 6 s, with 15 s providing approximately 1 log cycle greater reductions than 12 s of exposure. The 98.9 degrees C treatment was consistently the most effective, with exposure times of > or = 9 s resulting in >3.5 log CFU/cm2 reductions for all pathogens.

Animals↗

PubMed2005

Evaluation of small-scale hot-water postpackaging pasteurization treatments for destruction of Listeria monocytogenes on ready-to-eat beef snack sticks and natural-casing wieners.

This study was conducted to evaluate small-scale hot-water postpackaging pasteurization (PPP) as a postlethality (post-cooking) treatment for Listeria monocytogenes on ready-to-eat beef snack sticks and natural-casing wieners. Using a commercially available plastic packaging film specifically designed for PPP applications and 2.8 liters of boiling water (100 degrees C) in a sauce pan on a hot plate, an average reduction in L. monocytogenes numbers of > or = 2 log units was obtained using heating times of 1.0 min for individually packaged beef snack sticks (three brands) and 4.0 min for packages of four sticks (two brands) and seven sticks (three brands). Average product surface temperatures, measured as soon as possible after PPP and opening the package, were 47 to 51.5, 58 to 61.5, and 58.5 to 61 degrees C for the beef snack sticks packages of one, four, and seven sticks per package, respectively. A treatment of 7.0 min for packages of four natural-casing wieners (three brands) achieved L. monocytogenes reductions of > or = 1.0 log unit and average product surface temperature of 60.5 to 63.5 degrees C. Cooked-out fat and moisture resulting from tested treatments ranged from 0.2 to 1.1% by weight for beef snack sticks and from 0.4 to 1.2% by weight for natural-casing wieners. For natural-casing wieners, PPP had no detrimental effect on overall product desirability to consumers; results suggested that PPP may significantly enhance appearance of this product. However, for beef snack sticks the cooking out of fat and moisture during PPP had a significant negative effect on consumer opinions of product appearance.

Animals↗

PubMed2005

Antibiotic susceptibility of bacteria isolated from pasteurized milk and characterization of macrolide-lincosamide-streptogramin resistance genes.

The presence of antibiotic-resistant bacteria in pasteurized milk was detected by plating 18 milk samples on selective media containing beta-lactams, macrolides, or a glycopeptide. Most samples contained gram-positive bacteria that grew on agar plates containing oxacillin, erythromycin, and/or spiramycin. The disk-diffusion method confirmed resistance to erythromycin and/or spiramycin in 86 and 65% of the coryneform bacteria and Micrococcaceae tested, respectively. PCR and sequence analysis revealed the presence of an ermC gene in 2 of the 25 Micrococcaceae strains investigated for their resistance to erythromycin and/or spiramycin. None of the 14 corynebacteria strains resistant to erythromycin and/or spiramycin harbored the erm(X) gene. No gene transfer could be demonstrated between the two erm(C) staphylococcal isolates and recipient strains of Enterococcus faecalis JH2-2 or Staphylococcus aureus 80CR5.

Animals↗

PubMedDate not supplied

[The results of the registration clinical trials of the Act-Hib vaccine manufactured by the firm of Pasteur Mérieux Connaught, France].

The results of the field trials of the vaccine "Act-Hib" against Haemophilus influenzae of type b, presented for registration by Pasteur Mérieux Connaught (France), are summarized. The vaccine was found to have low reactogenicity and high immunological effectiveness. A single injection of the vaccine induced the formation of the protective level of anti-PRP antibodies in 94% of the immunized children aged 1-4 years. After immunization the mean geometric titers of specific antibodies increased sixfold in comparison with the initial level and were equal to 3.4 mu/ml. On the basis of the data of laboratory control and field clinical trials the vaccine "Act-Hib" was registered in the Russian Federation and permission and its practical use in the public health service of the country was permitted.

Antibodies, Bacterial↗

PubMed1999

[Microbiological quality of pasteurized milk creams manufactured in Venezuela].

A total of 100 samples of pasteurized milk creams produced by eleven (11) dairy milk industries were analyzed for the presence of microoganisms. The dairy milk industries were distributed along different places of Venezuela. The samples were analyzed for the presence of mesophilic aerobic bacteria, psychotropic bacteria, Staphylococcus aureus, coliformes, molds and yeasts 75% of the analyzed samples did not reach the international standards for aerobic mesophilic bacteria, similarly, 95% for Staphylococcus aureus, 91% for coliformes and 58% for molds and yeasts, so pathogenic enterobacteria we have found: Salmonella Typhimurium, Shigella sonnei and Escherichia coli enteropathogenic.

Animals↗

PubMed1999

[Toxoplasmosis at the Pasteur Institute of Bangui, Central African Republic (1996-1998): serological data].

A serological study of toxoplasmosis was conducted between 1996 and 1998 on 1953 patients of the Medical Analysis Laboratory of the Institut Pasteur de Bangui. The mean age of patients was 28 years. Among sera tested by ELISA, seropositivity to IgG antibodies was observed in 50.6%, and 2.6% sera were found positive for IgM antitoxoplasma antibodies (immuno-capture). The seroprevalence did not vary significantly according to sex or age. The results showed 40.8% sera had IgG antibodies titered 400 Ul/ml and more. The proportion of high level (> 400 Ul) IgG was more important in males than in females. High level IgG antibodies were statistically significant more frequently in the sera of females aged 10-29 years. Of the procreative women, 49.1% were at risk of contacting toxoplasmosis. The diagnosis of recently acquired infection, based on the coexistence of IgM antibodies and high level IgG antibodies, was noted in 1.6% among sera of procreative women. In the Central African Republic, serologic survey during pregnancy is not systematic and HIV seroprevalence is high (15%). Risks of acute infections during pregnancy and of opportunistic infections in HIV-infection patients are high. A control of toxoplasmosis is justifiable (screening during pregnancy, sanitary education) in CAR.

Adolescent↗

PubMed1999

Experience with vero cells at Pasteur Mérieux Connaught.

The Vero cell line has been used by Pasteur-Merieux-Connaught (PMC) since 1982 with the Cell Bank's system to produce, at the 142nd passage, inactivated polio vaccine (IPV), oral polio vaccine (OPV) and rabies vaccines. The safety of the cell line has been regularly validated at the WCB level according to the WHO and European Pharmacopeia requirements for absence of bacteria, fungi, mycoplasma and viruses. Special emphasis was devoted to establishing the absence of simian viruses (SV40, SIV, Retro-D virus, simian CMV). Reverse Transcriptase (RT) activity was also negative. At low level of passage, the Vero cells are not tumorigenic. Vaccines have been prepared in low passage level Vero cells and, together with the excellent downstream purification, has resulted in excellent safety as attested by pharmacovigilance of more than 100 million doses of IPV during 12 years, more than 20 million doses of rabies vaccine during 10 years and more than one billion of OPV during six years.

Animals↗

PubMedDate not supplied

[Characteristics of "Avaxim" hepatitis A vaccine produced by the firm "Pasteur Merrier" (results of field clinical trials)].

Controlled field clinical trials of Avaxim vaccine from hepatitis A (Pasteur-Merrier-Connot) were carried out in adults and children aged 3-14 years to evaluate its reactogenicity and antigenic properties. The vaccine was weakly reactogenic both in adults and children. A single injection of the vaccine resulted after 1 month in the production of anti-HAV antibodies in 77.4% initially seronegative adults and 94.5% children. In adults the mean geometrical titer of antibodies was 95 mIU/ml and in children 165 mIU/ml, which was 5-8 times higher than the protective titer. These data recommend Avaxim vaccine for practical public health.

Adolescent↗