Shelf Life

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Mareike Wenning - One of the best experts on this subject based on the ideXlab platform.

  • microbial biodiversity quality and Shelf Life of microfiltered and pasteurized extended Shelf Life esl milk from germany austria and switzerland
    International Journal of Food Microbiology, 2012
    Co-Authors: Verena S J Schmid, Ulrich Kulozik, Veronika Kaufma, Siegfried Schere, Mareike Wenning
    Abstract:

    Abstract Information on factors limiting the Shelf Life of extended Shelf Life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4 °C, 8 °C and 10 °C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of Shelf Life. It was observed that microfiltration decreased the microbial loads by 5–6 log 10 units to lower than 1 CFU/mL. However, bacterial counts at the end of Shelf Life were extremely variable and ranged between 10 CFU/mL. 8% of all samples showed spoilage indicated by cell counts higher than 6 log 10 CFU/mL. The main spoilage groups of bacteria were Gram-negative post-process recontaminants ( Acinetobacter , Chryseobacterium , Psychrobacter , Sphingomonas ) and the spore formers Paenibacillus and Bacillus cereus , while other spore formers and Microbacterium spp. did not reach spoilage levels. Paenibacillus spp. and B. cereus apparently influenced enzymatic spoilage, as indicated by increased free fatty acid production, pH 4.6 soluble peptide fractions and off-flavors. In some cases, enzymatic spoilage was observed although microbial counts were well below 6 log 10 CFU/mL. Thirteen B. cereus isolates were characterized for their toxin profiles and psychrotolerance. Hbl , nhe , and cytK toxin genes were detected in ten, thirteen, and four isolates, respectively, whereas the ces gene was always absent. Interestingly, only three of the thirteen isolates could be allocated to psychrotolerant genotypes, as indicated by the major cold shock cspA gene signature. Generally, large discrepancies in microbial loads and biodiversity were observed at the end of Shelf Life, even among packages of the same production batch. We suggest that such unexpected differences may be due to very low cell counts after ESL treatment, causing stochastic variations of initial species distributions in individual packages. This would result in the development of significantly different bacterial populations during cold storage, including the occasional development of high numbers of pathogenic species such as B. cereus or Acinetobacter .

  • Microbial biodiversity, quality and Shelf Life of microfiltered and pasteurized extended Shelf Life (ESL) milk from Germany, Austria and Switzerland
    International Journal of Food Microbiology, 2012
    Co-Authors: Verena S J Schmidt, Veronika Kaufmann, Siegfried Scherer, Ulrich Kulozik, Mareike Wenning
    Abstract:

    Information on factors limiting the Shelf Life of extended Shelf Life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4°C, 8°C and 10°C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of Shelf Life. It was observed that microfiltration decreased the microbial loads by 5-6 log10units to lower than 1CFU/mL. However, bacterial counts at the end of Shelf Life were extremely variable and ranged between

Verena S J Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • Microbial biodiversity, quality and Shelf Life of microfiltered and pasteurized extended Shelf Life (ESL) milk from Germany, Austria and Switzerland
    International Journal of Food Microbiology, 2012
    Co-Authors: Verena S J Schmidt, Veronika Kaufmann, Siegfried Scherer, Ulrich Kulozik, Mareike Wenning
    Abstract:

    Information on factors limiting the Shelf Life of extended Shelf Life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4°C, 8°C and 10°C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of Shelf Life. It was observed that microfiltration decreased the microbial loads by 5-6 log10units to lower than 1CFU/mL. However, bacterial counts at the end of Shelf Life were extremely variable and ranged between

Antonio Garridofernandez - One of the best experts on this subject based on the ideXlab platform.

  • study of the Shelf Life of ripe olives using an accelerated test approach
    Journal of Food Engineering, 2008
    Co-Authors: Pedro Garciagarcia, Antonio Lopezlopez, Antonio Garridofernandez
    Abstract:

    An Accelerated Shelf Life Test (ASLT) was carried out to estimate the Shelf Life of ripe olives (Californian style) as a function of firmness, colour and pH. Changes followed an apparent first-order kinetic. Their rates and activation energies were estimated from the response surface obtained from one-step non-linear fitting of the kinetic model to the experimental data as a function of temperature and time. There was a similar trend in the evolution of firmness, colour and pH rates with changes in temperature. Graphic representations of expected Shelf lives as a function of temperature and relative degradation for firmness, colour and pH are provided. Based on them, producers can deduce the appropriate Shelf Life for each specific storage condition and quality level. The current Shelf Life on the label (1080 days) was higher, when assessed for product firmness, than that found for a relative quality change of 0.20 at 30 °C in initially soft ripe olives. Exposure to higher temperatures markedly reduces Shelf Life.

  • study of the Shelf Life of ripe olives using an accelerated test approach
    Journal of Food Engineering, 2008
    Co-Authors: Pedro Garciagarcia, Antonio Lopezlopez, Antonio Garridofernandez
    Abstract:

    An Accelerated Shelf Life Test (ASLT) was carried out to estimate the Shelf Life of ripe olives (Californian style) as a function of firmness, colour and pH. Changes followed an apparent first-order kinetic. Their rates and activation energies were estimated from the response surface obtained from one-step non-linear fitting of the kinetic model to the experimental data as a function of temperature and time. There was a similar trend in the evolution of firmness, colour and pH rates with changes in temperature. Graphic representations of expected Shelf lives as a function of temperature and relative degradation for firmness, colour and pH are provided. Based on them, producers can deduce the appropriate Shelf Life for each specific storage condition and quality level. The current Shelf Life on the label (1080 days) was higher, when assessed for product firmness, than that found for a relative quality change of 0.20 at 30 °C in initially soft ripe olives. Exposure to higher temperatures markedly reduces Shelf Life.

Ulrich Kulozik - One of the best experts on this subject based on the ideXlab platform.

  • microbial biodiversity quality and Shelf Life of microfiltered and pasteurized extended Shelf Life esl milk from germany austria and switzerland
    International Journal of Food Microbiology, 2012
    Co-Authors: Verena S J Schmid, Ulrich Kulozik, Veronika Kaufma, Siegfried Schere, Mareike Wenning
    Abstract:

    Abstract Information on factors limiting the Shelf Life of extended Shelf Life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4 °C, 8 °C and 10 °C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of Shelf Life. It was observed that microfiltration decreased the microbial loads by 5–6 log 10 units to lower than 1 CFU/mL. However, bacterial counts at the end of Shelf Life were extremely variable and ranged between 10 CFU/mL. 8% of all samples showed spoilage indicated by cell counts higher than 6 log 10 CFU/mL. The main spoilage groups of bacteria were Gram-negative post-process recontaminants ( Acinetobacter , Chryseobacterium , Psychrobacter , Sphingomonas ) and the spore formers Paenibacillus and Bacillus cereus , while other spore formers and Microbacterium spp. did not reach spoilage levels. Paenibacillus spp. and B. cereus apparently influenced enzymatic spoilage, as indicated by increased free fatty acid production, pH 4.6 soluble peptide fractions and off-flavors. In some cases, enzymatic spoilage was observed although microbial counts were well below 6 log 10 CFU/mL. Thirteen B. cereus isolates were characterized for their toxin profiles and psychrotolerance. Hbl , nhe , and cytK toxin genes were detected in ten, thirteen, and four isolates, respectively, whereas the ces gene was always absent. Interestingly, only three of the thirteen isolates could be allocated to psychrotolerant genotypes, as indicated by the major cold shock cspA gene signature. Generally, large discrepancies in microbial loads and biodiversity were observed at the end of Shelf Life, even among packages of the same production batch. We suggest that such unexpected differences may be due to very low cell counts after ESL treatment, causing stochastic variations of initial species distributions in individual packages. This would result in the development of significantly different bacterial populations during cold storage, including the occasional development of high numbers of pathogenic species such as B. cereus or Acinetobacter .

  • Microbial biodiversity, quality and Shelf Life of microfiltered and pasteurized extended Shelf Life (ESL) milk from Germany, Austria and Switzerland
    International Journal of Food Microbiology, 2012
    Co-Authors: Verena S J Schmidt, Veronika Kaufmann, Siegfried Scherer, Ulrich Kulozik, Mareike Wenning
    Abstract:

    Information on factors limiting the Shelf Life of extended Shelf Life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4°C, 8°C and 10°C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of Shelf Life. It was observed that microfiltration decreased the microbial loads by 5-6 log10units to lower than 1CFU/mL. However, bacterial counts at the end of Shelf Life were extremely variable and ranged between

Petros S. Taoukis - One of the best experts on this subject based on the ideXlab platform.

  • Shelf-Life extension of gilthead seabream fillets by osmotic treatment and antimicrobial agents
    Journal of Applied Microbiology, 2012
    Co-Authors: Theofania N. Tsironi, Petros S. Taoukis
    Abstract:

    AIMS: The objectives of the study were to evaluate the effect of selected antimicrobial agents on the Shelf Life of osmotically pretreated gilthead seabream and to establish reliable kinetic equations for Shelf-Life determination validated in dynamic conditions. METHODS AND RESULTS: Fresh gilthead seabream (Sparus aurata) fillets were osmotically treated with 50% high dextrose equivalent maltodextrin (HDM, DE 47) plus 5% NaCl and 0·5% carvacrol, 0·5% glucono-δ-lactone or 1% Citrox (commercial antimicrobial mix). Untreated and treated slices were aerobically packed and stored isothermally (0-15°C). Microbial growth and quality-related chemical indices were modelled as functions of temperature. Models were validated at dynamic storage conditions. Osmotic pretreatment with the use of antimicrobials led to significant Shelf-Life extension of fillets, in terms of microbial growth and organoleptic deterioration. CONCLUSIONS: The Shelf Life was 7 days for control samples at 5°C. The osmotic pretreatment with carvacrol, glucono-δ-lactone and Citrox allowed for Shelf-Life extension by 8, 10 and 5 days at 5°C, respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the study show the potential of adding carvacrol, glucono-δ-lactone or Citrox in the osmotic solution to extend the Shelf Life and improve commercial value of chilled osmotically pretreated fish products. The developed models can be a reliable tool for predicting the Shelf Life of fresh or minimally processed gilthead seabream fillets in the real chill chain.

  • application of Shelf Life decision system slds to marine cultured fish quality
    International Journal of Food Microbiology, 2002
    Co-Authors: Konstantinos P Koutsoumanis, Petros S. Taoukis, M C Giannakourou, Georgejohn E Nychas
    Abstract:

    Growth of natural microflora of marine cultured, air-packed, sea bass (Dichentrachus labrax) was studied at isothermal conditions in the 0-15 degrees C range and kinetically modelled using the four-parameter Logistic equation. Sensory Shelf Life was correlated to pseudomonad population and sensory acceptability was correlated to a pseudomonad level, Ns, of 10(7). The variability of their initial population was quantitatively shown and a conductance-based rapid method specific to sea bass pseudomonad enumeration was established as a practical means of N0 determination, required in Shelf Life predictions. Kinetic models, Shelf Life correlations and N0 data were incorporated into the Shelf Life decision system (SLDS) shown to be an effective tool for marine cultured sea bass chill chain management leading to optimization of quality of the fish at consumer's end.

  • evaluation of Shelf Life of flavored dehydrated products using accelerated Shelf Life testing and the weibull hazard sensory analysis
    Developments in food science, 1998
    Co-Authors: M. Bili, Petros S. Taoukis
    Abstract:

    Abstract The Shelf Life of foods is a function of their composition, processing, packaging and environmental factors, most notably temperature. For dehydrated foods, end of Shelf Life is usually signaled by an unacceptable loss of sensory attributes. Since the time to reach this level of unacceptability, under normal storage conditions, is targeted to be 12 to 24 months, techniques of Accelerated Shelf Life Testing (ASLT) are employed to determine the Shelf Life of such products within a reasonable length of time. Use of Weibull Hazard Analysis facilitates the effective application of ASLT with sensory evaluation by allowing the use of a practical panel size and easy quantitation of the results. These can be used to model the Shelf Life behavior and to extrapolate from accelerated to normal conditions. The degradation of the intense sweetener aspartame was studied in a gelatin-based dessert with a fruity flavor. Tests were conducted at 45, 50 and 60°C and the end of Shelf Life, expressed as unacceptably low level of sweetness, was determined by sensory evaluation as 70.4, 51.9 and 24.3 days respectively. An activation energy of degradation of aspartame, E A , was calculated as 15.1 kcal/mol, from which a Shelf Life for the product stored at 20°C of 554 days was estimated. Sensory results correlated very well with HPLC measurements of the aspartame degradation giving practically the same E A , and showing that end of Shelf Life coincided in all cases with 60% remaining aspartame.