Spore-forming bacteria in commercial cooked, pasteurised and chilled vegetable purées

Carlin, Frédéric; Guinebretière, Marie-Hélène; Choma, Caroline; Pasqualini, Roselyne; Braconnier, Agnès; Nguyen-Thé, Christophe

doi:10.1006/fmic.1999.0299

Cited by 121 publications

(64 citation statements)

References 18 publications

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“…The hot fill packaging process does not inactivate bacteria of the Bacillus species, as mild pasteurization cannot inactivate these heat resistant bacteria, which are present in some sauce products. This may limit their shelf life, particularly under extreme temperature conditions (10,11). Some low pH products such as meat extract solution, watery kimchi meat solution, and soy sauce/vinegar mix seemed to rely solely on a low pH for their preservation.…”

Section: Resultsmentioning

confidence: 99%

Storage Stability and Shelf Life Characteristics of Korean Savory Sauce Products

Yun¹,

Cha²,

Lee³

2007

JFN

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This study evaluated the storage stability of a variety of sauce products in the Korean market, determined primary quality indices for three typical products, and proposed functional relationships that are useful for determining shelf life at different temperatures. Most of the products examined were found to combine hurdles of low pH, low water activity, and the use of heat processing as methods for producing the required storage stability while maintaining the sensory quality of the products. For a meat extract solution produced for cold noodles (pH＝4.3; aw＝0.98), the primary quality change determining shelf life was lipid oxidation, determined here by the TBA value. The primary quality index of a soybean paste seasoning mix (pH＝4.0; aw＝0.78), which had a microbial load of 2.8 log (CFU/g), was a decrease in its pH. The primary quality index for a sandwich spread (pH＝4.0; aw＝0.88) was changes in its surface color. The temperature dependence of changes in the primary quality indices can be described by the Arrhenius equation, which can estimate the shelf life at any arbitrary limit as a function of temperature. The activation energies for changes in the primary quality indices of the meat extract solution, the soybean paste seasoning, and the sandwich spread were 20.3, 27.2, and 43.5 kJ/mol, respectively.

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Section: Resultsmentioning

confidence: 99%

Storage Stability and Shelf Life Characteristics of Korean Savory Sauce Products

Yun¹,

Cha²,

Lee³

2007

JFN

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“…Thus, it is important to develop sensitive tools for detection of spoilage organisms and to apply them throughout the processing chain to identify entry points to enable development of control strategies to reduce spoilage and improve the quality of our foods. In the future, our assay could be extended to other refrigerated and pasteurized foods, including processed vegetables (2,7,15), where psychrotolerant Paenibacillus organisms are a potential spoilage concern.…”

Section: Discussionmentioning

confidence: 99%

“…The results of this study will provide the food industry with an assay to monitor the quality of raw milk. This assay may even be adapted to aid in the development of strategies to limit spoilage of other pasteurized, refrigerated foods like vegetable purees (2,15) and fermented beverages (17). Finally, our assay has potential for use as a screening tool to isolate novel enzyme-producing Paenibacillus spp.…”

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confidence: 99%

Real-Time PCR Detection of Paenibacillus spp. in Raw Milk To Predict Shelf Life Performance of Pasteurized Fluid Milk Products

Ranieri

Ivy

Mitchell

et al. 2012

Appl Environ Microbiol

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Psychrotolerant sporeformers, specifically Paenibacillus spp., are important spoilage bacteria for pasteurized, refrigerated foods such as fluid milk. While Paenibacillus spp. have been isolated from farm environments, raw milk, processing plant environments, and pasteurized fluid milk, no information on the number of Paenibacillus spp. that need to be present in raw milk to cause pasteurized milk spoilage was available. A real-time PCR assay targeting the 16S rRNA gene was designed to detect Paenibacillus spp. in fluid milk and to discriminate between Paenibacillus and other closely related spore-forming bacteria. Specificity was confirmed using 16 Paenibacillus and 17 Bacillus isolates. All 16 Paenibacillus isolates were detected with a mean cycle threshold (C T ) of 19.14 ؎ 0.54. While 14/17 Bacillus isolates showed no signal (C T > 40), 3 Bacillus isolates showed very weak positive signals (C T ‫؍‬ 38.66 ؎ 0.65). The assay provided a detection limit of approximately 3.25 ؋ 10 1 CFU/ml using total genomic DNA extracted from raw milk samples inoculated with Paenibacillus. Application of the TaqMan PCR to colony lysates obtained from heat-treated and enriched raw milk provided fast and accurate detection of Paenibacillus. Heat-treated milk samples where Paenibacillus (>1 CFU/ml) was detected by this colony TaqMan PCR showed high bacterial counts (>4.30 log CFU/ ml) after refrigerated storage (6°C) for 21 days. We thus developed a tool for rapid detection of Paenibacillus that has the potential to identify raw milk with microbial spoilage potential as a pasteurized product. Despite advances in food preservation techniques, bacterial spoilage remains a leading cause of global food loss (14). Nearly one-third of all food produced worldwide is estimated to be lost postharvest, and much of this loss can be attributed to microbial spoilage (16). Dairy products constitute one of the leading sectors impacted by food loss in the United States, as nearly 20% of conventionally pasteurized (high temperature, short time [HTST]) fluid milk is discarded prior to consumption each year (23). In the United States, the shelf life of fluid milk ranges from approximately 1 to 3 weeks. Most consumer complaints result from the growth of psychrotolerant bacteria, typically, either nonspore-forming Gram-negative rods or Gram-positive sporeforming bacteria (12,18,19,28,34,39). The presence of psychrotolerant, non-spore-forming bacteria (e.g., Pseudomonas) in pasteurized milk indicates either inadequate heating of the milk or, more commonly, postpasteurization contamination (6). Therefore, pasteurized milk contamination with Pseudomonas and other non-spore-forming bacteria can be controlled or eliminated by adhering to pasteurization specifications for minimum time and temperature combinations (8) and by adhering to proper sanitation and equipment maintenance protocols, particularly with respect to milk filler sites (33). Conversely, Grampositive psychrotolerant sporeformers can survive pasteurization as spores, germinate, and then grow ...

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“…Spoilage data that are available (e.g. Carlin et al, 2000b) could not be used to derive such a model. As an alternative, we use the main characteristic of the square root model for the growth rate (Ratkowsky et al, 1982) to express the relative importance of time and temperature in a 'spoilage model', a very simple version of a time temperature integrator (Taoukis and Labuza, 1989;Taoukis et al, 1999).…”

Section: Spoilage and Maximum Population Densitymentioning

confidence: 99%

A retail and consumer phase model for exposure assessment of Bacillus cereus

Nauta

2003

International Journal of Food Microbiology

106

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An exposure assessment is conducted for psychrotrophic and mesophilic Bacillus cereus in a cooked chilled vegetable product. A model is constructed that covers the retail and consumer phase of the food pathway, using the output of a similar model on the industrial process as input. Microbial growth is the predominant process in the model. Variability in time and temperature during transport and storage is included in the model and different domestic refrigerator temperature distributions are compared. As an end point, probable levels of B. cereus colony forming units (cfu) in packages of vegetable purée are predicted at the moment the consumer takes the product from its refrigerator, that is prior to a cooking process. The psychrotrophic strain is predicted to end up above a threshold level of 10 5 cfu/g in 0.9% to 6.3% of the vegetable purée packages, depending on domestic refrigerator temperature. Accounting for spoilage this reduces to 0.3% to 2.4%. Even if the purée is stored at 4 jC in the domestic refrigerator and use-by-date (UBD) is respected, the threshold level may be passed. For the mesophilic strain the threshold level is rarely passed, but in contrast to the total viable count, the spore load at the end point is predicted to be higher than in the psychrotrophic strain. Our study illustrates how an exposure assessment model, which may be used in quantitative risk assessment, can integrate expertise in modelling, food processing and microbiology over the food pathway, and thus evaluate food safety, identify gaps in knowledge and compare risk management measures. As important gaps in knowledge, the lack of sporulation and germination models and data, validated non-isothermal growth models and a spoilage model useful for risk assessment are identified. Knowledge of the dose -response relationship is limited and does not allow a full risk assessment. It is shown that exposure can be lowered by lowering domestic refrigerator temperatures, and less so much by monitoring and withdrawing contaminated products at the end of industrial processing. D

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Spore-forming bacteria in commercial cooked, pasteurised and chilled vegetable purées

Cited by 121 publications

References 18 publications

Storage Stability and Shelf Life Characteristics of Korean Savory Sauce Products

Storage Stability and Shelf Life Characteristics of Korean Savory Sauce Products

Real-Time PCR Detection of Paenibacillus spp. in Raw Milk To Predict Shelf Life Performance of Pasteurized Fluid Milk Products

A retail and consumer phase model for exposure assessment of Bacillus cereus

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