Aabo, Søren

Gunvig, Annemarie

Hansen, Flemming

Hansen, Tina Beck

Online Research Database In Technology

Gaining more from pilot-plant studies: An example for VTEC in fermented semi-dried sausages

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 18, 2017Gaining more from pilot-plant studies: An example for VTEC in fermented semi-driedsausagesHansen, Tina Beck; Gunvig, Annemarie; Hansen, Flemming; Aabo, SørenPublication date:2010Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Hansen, T. B., Gunvig, A., Hansen, F., & Aabo, S. (2010). Gaining more from pilot-plant studies: An example forVTEC in fermented semi-dried sausages. Poster session presented at 22nd International ICFMH Symposium,Copenhagen, Denmark.FIG. 3. Confidence in log-reductions obtained during production of semi-dried sausagesFIG. 2. Survival of VTEC in broth model systemsGaining more from pilot-plant studies: an example for VTECin fermented semi-dried sausagesTina Beck Hansen1, Annemarie Gunvig2, Flemming Hansen2 and Søren Aabo11 National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark2 DMRI, Danish Technological Institute, Maglegaardsvej 2, DK-4000 Roskilde, DenmarkINTRODUCTION & OBJECTIVEA pilot-plant study often test behaviour of cocktails of strainsgiving the opportunity to cover more biological variability inthe study. However, a possible strain variation will be masked,as the most tolerant strain will be the one recovered andenumerated.In the present work, VTEC with different indigenous antibioticresistant markers were used to disclose the biologicalvariability between strains during production of fermentedsemi-dried sausages.CONCLUSIONS Strain variability increased with addition of NaNO2 to thesausage batter (Fig. 1) Strain variability occurred earlier for 4 and 6 compared to5 % water phase salt (WPS) in the sausage batter (Fig. 1) Strain variability was unaffected by type of starter used inthe sausage Strain variability in broth was inconsistent with resultsobtained in semi-dried sausages (Fig. 2) Low NaNO2 combined with low WPS gave the highest  log-reduction as well as the highest confidence (Fig. 3)   FIG. 1. Survival of VTEC during production of semi-dried sausagesMATERIALS & METHODSA cocktail of equal volumes of VTEC O26, O111 and O157, were prepared from overnightcultures grown in BHI at 37 C for 24 h. Three independent pilot-plant studies wereperformed where the cocktail was added during chopping of the meat. Survival duringproduction of fermented, semi-dried sausages were investigated. Fermentations wereperformed at 24 C for 48 h, drying at 16 C until 35 % weight loss. Agar substrates withrelevant antibiotics were developed to recover each of the strains separately (Tab. 1). Thestudies covered recipes with varying water phase salt (WPS) contents (approx. 4, 5 and6%), sodium nitrite levels (0, 100 and 200 ppm) and starter cultures (F-1 Bactoferm andFSC 111 Bactoferm from Chr. Hansens A/S) used in the batter.TAB. 1. Counts (log10CFU/mL) of overnight VTEC cultures (BHI, 37°C)RESULTSPooled results from three pilot-plant studies(Fig. 1) showed that independent on WPScontent and starter culture, the strainvariability was lowest when no NaNO2 wasused. In sausages, with added NaNO2 (100and 200 ppm), containing 4 % or 6 % WPS,strain variability typically peaked after 10 d,whereas in sausages with 5 % WPS, strainvariability was highest after 24 d. Thischange in strain variability during productionwas primarily a result of low survival ofO111, as compared to O26 and O157.These observations were inconsistent withthe survival observed in broths containinglevels of lactate (Fig. 2 – pH) and NaCl (Fig.2 – WPS) comparable to the sausages.Modelling the survival of VTEC obtainedafter 24 d showed the highest confidence inlog-reduction estimates for the sausagesprepared from batter containing 4 to 4.5 %WPS and 0 to 50 ppm NaNO2 (Fig. 3).VTEC strainBHI agar SMaC CT-SMaC MaCMaC + 64 µg/L streptomycinMaC + 16 µg/L neomycinO26 9.43 9.34 Growth(red) 9.48Nogrowth 9.23O111 9.61 9.62 NoGrowth 9.66 9.49NogrowthO157 9.51 9.57 9.43 (colourless) 9.48NogrowthNogrowthStarter culture F-1 Bactoferm, production dayConcentration of VTEC in product (log 10CFU/g)01234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 2801234560 7 14 21 284 % WPS 5 % WPS 6 % WPS0 ppm NaNO2 0 ppm NaNO2 0 ppm NaNO2100 ppm NaNO2 100 ppm NaNO2 100 ppm NaNO2200 ppm NaNO2 200 ppm NaNO2200 ppm NaNO2VTEC O26     VTEC O111     VTEC O157log 10CFU/mLIncubation at 16°C, daysVTEC O26     VTEC O111     VTEC O1570123456780 2 4 6 8 10 12 14 160123456780 2 4 6 8 10 12 14 166 % (full line)12 % (dotted line) 4.5 (dotted line)5.0 (full line)pH WPS% WPS4 4.5 5 5.5 60501001502004.5-54-4.53.5-43-3.54 4.5 5 5.5 60501001502000.6-0.80.4-0.60.2-0.40-0.2% WPSNaNO2(ppm)Log-reduction Standard deviationLog-reductionEXAMPLE:4.5 % WPS75 ppm NaNO200.10.20.30.40.50.60.70.82 3 4 5 6Predicted NORM (4.1,0.48)For further details contact Tina Beck Hansen, email tibha@food.dtu.dk

http://orbit.dtu.dk/ws/files/96497542/VTEC_poster260810.pdf

Gaining more from pilot-plant studies: An example for VTEC in fermented semi-dried sausages

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology

Online Research Database In Technology