Location: Meat Safety and QualityTitle: Attachment of GFP-producing Escherichia coli O103 on beef tissues over time
|BRETHOUR, BROCK - Kansas State University|
|Bosilevac, Joseph - Mick|
|MAHER, JOSHUA - Kansas State University|
|STULL, KATELYNN - University Of Florida|
|GRAGG, SARA - Kansas State University|
Submitted to: Journal of Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2020
Publication Date: 8/2/2020
Citation: Brethour, B., Bosilevac, J.M., Maher, J., Stull, K.J., Gragg, S. 2020. Attachment of GFP-producing Escherichia coli O103 on beef tissues over time. [Abtract]. International Association for Food Protection Conference, Cleveland Ohio, August 2-5, 2020, Virtual. Journal of Food Protection. 83(Supplement A):P2-92.
Technical Abstract: Introduction: Escherichia coli O103 is a Shiga toxin-producing bacterium associated with foodborne illness outbreaks in beef. An avirulent E. coli O103 strain possessing green fluorescent protein (GFP) may be an effective surrogate simulating Shiga toxin-producing Escherichia coli (STEC) behavior in beef; however, attachment characteristics must be investigated prior to use as a STEC surrogate. Purpose: This study investigated attachment of an avirulent, GFP-E. coli O103 to lean and adipose beef tissues over time. Methods: Beef brisket was purchased from a local grocer, cut into 50cm2 (lean or adipose) tissue samples, inoculated with GFP-E. coli O103 prepared in Tryptic Soy Broth (TSB) or Purge, stored at 4°C, and enumerated at 0, 3, 5, and 20, 60, 180, 480, 720, 1,440, and 2,880 minutes. Inoculated brisket was homogenized for 1 min at 230rpm in 250 mL 0.1% peptone water (PW) and shaken at 200 rpm for 90 s in an orbital shaker (loose); immediately following, the same brisket was transferred to a second stomacher bag with 250 mL PW and homogenized a second time for 60 s at 230 rpm (firm). Loose and firm samples were enumerated using TSA+ampicillin and MacConkey Agars, and then incubated at 37°C for 18-24 h. Results: The main effects sample type (loose or firm) and time were statistically significant (P<0.0001). The sample type*tissue (lean or adipose; P=0.0004), sample type*diluent liquid (TSB or Purge; P=0.0228), and sample type*time (P=0.0039) interactions were all significant, indicating that GFP-E. coli O103 more firmly attached to adipose beef tissue and loosely attached populations decreased throughout storage. Significance: Observed attachment of GFP-E. coli O103 to beef tissues was impacted by fat content and time. Similar research conducted with STEC suggests GFP-E. coli O103 attachment to beef tissues is comparable to STEC, demonstrating possible STEC surrogate potential; however, further investigation is needed.