Factors Influencing Growth and Toxin Production in Cheese Inoculated with Spores of Clostridium Botulinum Types A and B. I. Studies with Surface-Ripened Cheese Type I

Wagenaar, R. O.; Dack, G. M.

doi:10.3168/jds.s0022-0302(58)91072-5

Cited by 18 publications

(14 citation statements)

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“…botulinum type B proteolytic is well able to grow in the cheese spread used in this example. Considering the good safety record of processed cheese ( Wagenaar and Dack 1958; Collins‐Thompson and Wood 1993), it is assumed that prevalence is very low, but quantitative estimation of prevalence ( P e ) was not possible with the available information. For that reason, risk was estimated with P e ranging from 10 −20 to 1 ( Table 6, row 4).…”

Section: Resultsmentioning

confidence: 99%

Stepwise quantitative risk assessment as a tool for characterization of microbiological food safety

et al. 2000

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2000. This paper describes a system for the microbiological quantitative risk assessment for food products and their production processes. The system applies a stepwise risk assessment, allowing the main problems to be addressed before focusing on less important problems. First, risks are assessed broadly, using order of magnitude estimates. Characteristic numbers are used to quantitatively characterize microbial behaviour during the production process. These numbers help to highlight the major risk-determining phenomena, and to ®nd negligible aspects. Second, the risk-determining phenomena are studied in more detail. Both general and/or speci®c models can be used for this and varying situations can be simulated to quantitatively describe the risk-determining phenomena. Third, even more detailed studies can be performed where necessary, for instance by using stochastic variables. The system for quantitative risk assessment has been implemented as a decision supporting expert system called SIEFE: Stepwise and Interactive Evaluation of Food safety by an Expert System. SIEFE performs bacterial risk assessments in a structured manner, using various information sources. Because all steps are transparent, every step can easily be scrutinized. In the current study the effectiveness of SIEFE is shown for a cheese spread. With this product, quantitative data concerning the major risk-determining factors were not completely available to carry out a full detailed assessment. However, this did not necessarily hamper adequate risk estimation. Using ranges of values instead helped identifying the quantitatively most important parameters and the magnitude of their impact. This example shows that SIEFE provides quantitative insights into production processes and their risk-determining factors to both risk assessors and decision makers, and highlights critical gaps in knowledge.

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Section: Resultsmentioning

confidence: 99%

Stepwise quantitative risk assessment as a tool for characterization of microbiological food safety

et al. 2000

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“…However, they received 0.2% locust bean gum powder as stabilizer, a substance that is routinely added to many cheese products to prevent separation of brine water from the product. The addition of 0.2% locust bean gum had no effect on growth and toxin production of C. botulin~rn in experimental cheese preparations (Wagenaar and Dack, 1958).…”

Section: Methodsmentioning

confidence: 99%

“…Cheese preparations. Cheese preparations were made as described by Wagenaar and Dack (1958) from type I cheese, a soft surface-ripened cheese the flora of which was made up of bacteria and yeasts. Approximately 10% water was added to the cheese to yield a NaCl-brine concentration favorable to growth of C. botuli?tu~z in the basic product.…”

Section: Methodsmentioning

confidence: 99%

Toxin Production in Naturally Separated Liquid and Solid Components in Preparations of Heated Surface‐Ripened Cheese Inoculated with Clostridium botulinum

Grecz

Dack

1963

Journal of Food Science

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SUMMARY Occasional solid‐liquid separation of soft surface‐ripened cheese packed into test tubes was examined for differences between the components with regard to growth and toxin production of Clostridium botulinum. Botulinum toxin was found in three tubes showing liquid‐solid separation; in each case the toxin was present in the solid but absent from the liquid cheese portion. Two mechanisms were found to be responsible for the peculiar distribution of toxin in liquid‐solid separated cheese: 1) the liquid portion possessed antimicrobial activity preventing the growth of C. botulinum whereas the solid component was antimicrobially inactive; 2) the particles in the solid cheese were able to adsorb botulinum toxin, thus preventing diffusion of preformed toxin into the liquid layer. Separation into a solid and liquid layer could be achieved deliberately by increase of the moisture content of the cheese preparation, or by mixing of thoroughly ripened cheese with relatively fresh cheese. However, in these tubes the toxin—when present—was distributed in essentially equal quantities in the adjacent solid and liquid components.

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“…The viable count was based on heating the final dilutions in flowing steam for 15 min and on using a deep-tube counting procedure with 10 replicates per dilution. The counting medium consisted of 5% Trypticase (Baltimore Biological Laboratory, Baltimore, Maryland), 0.5% Peptone (Difco) and 1.5% Noble Agar (Difco) as adapted from Wagenaar and Dack (1958). Colony counts were made after approximately 40 h of incubation at 30°C.…”

Section: Preparation and Standardization Of Spore Suspensionmentioning

confidence: 99%

BIOLOGICAL EVALUATION of A HEAT TRANSFER SIMULATION FOR STERILIZING LOW-ACID LARGE PARTICULATE FOODS FOR ASEPTIC PACKAGING

Segner

Ragusa

Marcus

et al. 1989

J Food Processing Preservation

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A biological procedure was devised to evaluate de Ruyter and Brunet's heat transfer computer simulation for sterilizing particulate foods in a swept surface heat exchanger (SSHE). Turkey cubes measuring 12.7 mm were inoculated with spores of Clostridium sporogenes PA3679, using a so‐called “knotted string” method. Inoculated cubes were introduced into a viscous starch medium and thermally processed in a SSHE to a fractional survivor endpoint. Processed product was packaged aseptically, incubated and examined for survivors. Biological sterilization values calculated from the inoculated packs support the validity of the simulation. Also, a novel method was devised to measure particle residence times in hold tubes using electro‐magnetic induction.

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Factors Influencing Growth and Toxin Production in Cheese Inoculated with Spores of Clostridium Botulinum Types A and B. I. Studies with Surface-Ripened Cheese Type I

Cited by 18 publications

References 0 publications

Stepwise quantitative risk assessment as a tool for characterization of microbiological food safety

Stepwise quantitative risk assessment as a tool for characterization of microbiological food safety

Toxin Production in Naturally Separated Liquid and Solid Components in Preparations of Heated Surface‐Ripened Cheese Inoculated with Clostridium botulinum

BIOLOGICAL EVALUATION of A HEAT TRANSFER SIMULATION FOR STERILIZING LOW-ACID LARGE PARTICULATE FOODS FOR ASEPTIC PACKAGING

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