Project Summry Decontmintion of Beef Cuts Intended for Blde/Needle or Moisture-Enhncement Tenderiztion by Surfce Trimming versus Rinsing with Solutions of Hot (82 C) Wter, Wrm (55 C) Lctic Acid or Activted Lctoferrin Plus Wrm (55 C) Lctic Acid Principl Investigtors: John Scng, Ph.D., John Sofos, Ph.D., Keith Belk, Ph.D. nd Gry Smith, Ph.D., Colordo Stte University Study Completed Februry 2005 Funded by The Beef Checkoff
Decontmintion of Beef Cuts, Intended for Blde/Needle or Moisture- Enhncement Tenderiztion by Surfce Trimming versus Rinsing with Solutions of Hot (82 C) Wter, Wrm (55 C) Lctic Acid or Activted Lctoferrin Plus Wrm (55 C) Lctic Acid: Project Summry Bckground Reserch hs shown tht the incidence of E. coli O157:H7 on surfces of beef cuts intended for blde or needle tenderiztion is extremely rre. One study showed 0.2 percent occurrence of E. coli O157:H7 on 1,014 cuts from six processing fcilities throughout the United Sttes. The fct tht E. coli O157:H7 rrely occurs on beef priml nd subpriml cuts mkes the risk of its internliztion when blde, needle or moisture enhncement tenderiztion technologies re used very low. Even though the risks re low, the probbility of its occurrence is drmticlly incresed if improper clening nd snitizing of equipment is prcticed. Pst reserch hs lso shown tht blde tenderiztion cn trnsfer from 1 to 7 percent of surfce contmintion to the interior of the muscle. Needle injection during moisture enhncement cn result in 4 to 8 percent trnsloction of surfce contmintion to the center of the cut. While cooking needle tenderized or moisture enhnced product to sufficient internl tempertures (140 F or higher) hs been shown to destroy E. coli O157:H7, intervention methods pplied prior to tenderiztion should help prevent the trnsfer of bcteri to internl surfces, thus reducing ny risks of foodborne pthogens being pssed to consumers. Methodology Outside rounds were obtined from commercil pcking compny nd cut into equl hlves. The rounds were inoculted with E. coli O157:H7 nd were individully vcuum pckged nd stored for 10 to 18 dys t 2 to 4 C. Smples were suspended from sterilized met hook nd one of five pthogen interventions ws pplied to ech outside round piece: 1) No tretment 2) Surfce trim using good mnufcturing prctices 3) 20 second hot (82 C) wter spry ppliction 4) 20 second wrm (55 C) 5 percent lctic cid spry ppliction 5) Sequentil ppliction of ctivted lctoferrin (20 seconds) followed by wrm (55 C) lctic cid (20 second spry) After the intervention tretment, the outside round pieces were llowed to sit for five minutes before undergoing blde tenderiztion or moisture enhncement to simulte in-plnt line speed. Study A Outside round pieces (n = 120) were inoculted with trget of 10 2 CFU/cm 2 of E. coli O157:H7. Following storge, individul round pieces were subjected to one of the five bcteril interventions (n = 24 per intervention) nd were subjected to either blde tenderiztion (n = 60; n = 12 per intervention per process) or needle-injected enhncement (n = 60; n = 12 per
intervention per process). Smples were nlyzed for E. coli O157:H7 using polymerse chin rection (PCR). Study B Outside round pieces (n = 160) were inoculted nd interventions were pplied s described bove (n = 32 per intervention) nd subjected to either blde tenderiztion (n = 80; n = 16 per intervention per process) or needle enhncement (n = 80; n = 16 per intervention per process). Following processing, five centimeter slice ws removed from ech piece, which ws subsequently split into two, 2.5 centimeter thick slices. A surfce sponge smple ws then collected from newly exposed internl surfce of one slice. Surfce smples were nlyzed to quntittively determine the surfce popultions of E. coli O157:H7 by direct plting nd counting morphologiclly typicl colonies. All results were reported in log colony forming units per cm 2 (CFU/cm 2 ). Uninoculted (n = 40) outside round pieces were lso subjected to the interventions nd processing tretments s previously described, so tht there ws totl of four smples per intervention nd per process. Findings Study A The prevlence of E. coli O157:H7 found within outside round pieces ws 99.2 percent (119 out of 120 smples). Only one smple, snitized with hot (82 C) wter nd needle-injected did not return positive result. The high rtes cn be ttributed to the fct tht the inocultion levels used in this study re fr higher thn levels of E. coli O157:H7 one would expect to find on uninoculted beef surfces. Tble 1. Number of positive smples/number of smples tested (percent positive) for prevlence of E. coli O157:H7, s determined by PCR-BAX, fter inoculted outside round pieces were subjected to one of four ntimicrobil interventions nd were blde-tenderized (BT) or moisture-enhnced (ME). Inoculted, untreted outside-rounds served s positive controls. Positive Trimming b Hot Wter Control (82 C) c Wrm 5% Lctic Activted Lctoferrin + 5% Lctic Acid BT 12/12 (100) 12/12 (100) 12/12 (100) 12/12 (100) 12/12 (100) ME 12/12 (100) 12/12 (100) 11/12 (91.7) 12/12 (100) 12/12 (100) b Smples were crefully trimmed to remove ll externl surfces prior to further processing.
Study B Product Storge Outside rounds were vcuum pckged nd stored (2 C) for 10 to 18 dys fter inocultion. At the time of inocultion, the smples hd surfce levels of E. coli O157:H7 of 2.17 log CFU/cm 2. Following vcuum pckging nd refrigerted storge, surfce smples were collected prior to ppliction of ny ntimicrobil tretments or further processing. During storge, inoculted popultions incresed from n verge of 2.17 log CFU/cm 2 to 3.4 to 3.7 log CFU/cm 2. These results indicte tht E. coli O157:H7, when present in high levels cn survive nd grow in vcuum pckges t refrigerted tempertures. Antimicrobil Interventions Intervention tretments resulted in 0.9 to 1.1 log CFU/cm 2 reduction compred to preintervention inoculted inside round surfce smples. Survivl of E. coli O157:H7 rnged from 12.3 to 17.3 percent of pre-intervention surfce levels nd ll interventions eqully reduced the presence of pthogens on the surfce level. Tble 2. Lest squre mens ± stndrd errors for E. coli O157:H7 (log CFU/cm 2 ) recovered from the externl surfce (minimum detection level = 1.0 CFU/cm 2 ) of inoculted outside round pieces prior to ppliction of n ntimicrobil intervention (PRE) nd following n ntimicrobil intervention (POST), nd internl surfce levels of E. coli O157:H7 (CFU/cm 2 ) following moisture enhncement (ME). Inoculted, untreted outsiderounds served s positive controls (n = 16 for ech intervention tretment). Positive Trimming b Hot Wter Control (82 C) c Wrm 5% Lctic Activted Lctoferrin + 5% Lctic Acid PRE - 3.7 ± 0.08 x 3.6 ± 0.08 x 3.6 ± 0.08 x 3.6 ± 0.08 x POST 3.6 ± 0.08 x 2.6 ± 0.08 y 2.5 ± 0.08 y 2.4 ± 0.08 y 2.7 ± 0.08 y ME 2.1 ± 0.08 y 1.3 ± 0.08 z 1.2 ± 0.08 z 1.2 ± 0.08 z 1.4 ± 0.08 z b Smples were crefully trimmed to remove ll externl surfces prior to further processing. x, y, z Lest squres mens, within columns, lcking common superscript letters, differ (P < 0.05).
Tble 3. Lest squre mens ± stndrd errors for E. coli O157:H7 (log CFU/cm 2 ) recovered from the externl surfce (minimum detection level = 1.0 CFU/cm 2 ) of inoculted outside round pieces prior to ppliction of n ntimicrobil intervention (PRE) nd following n ntimicrobil intervention (POST), nd internl surfce levels of E. coli O157:H7 (CFU/cm 2 ) following blde tenderiztion (ME). Inoculted, untreted outsiderounds served s positive controls (n = 16 for ech intervention tretment). Positive Control Trimming b Hot Wter (82 C) c Wrm 5% Lctic Activted Lctoferrin + 5% Lctic Acid PRE - 1.0 ± 0.06 0.9 ± 0.06 1.0 ± 0.06 1.2 ± 0.06 POST 0.9 ± 0.06 0.9 ± 0.06 0.9 ± 0.06 0.9 ± 0.06 0.9 ± 0.06 ME 0.9 ± 0.06 0.9 ± 0.06 0.9 ± 0.06 0.9 ± 0.06 0.9 ± 0.06 b Smples were crefully trimmed to remove ll externl surfces prior to further processing. Implictions Results of this study indicte tht even when surfce levels of E. coli O157:H7 re severl hundred fold higher thn those reported in ntionl surveys, ppliction of ntimicrobil interventions of surfce trimming, hot wter (82 C), 5 percent lctic cid (55 C) or ctivted lctoferrin plus 5 percent lctic cid (55 C), cn reduce pthogen lods on the surfce of subpriml cuts. For those subprimls subjected to further processing, the interventions cn subsequently reduce internliztion of surfce pthogens. Both blde tenderiztion nd moisture enhncement resulted in pthogen trnsmission into internl surfces of inoculted subprimls. Moisture enhncement resulted in the gretest trnsmission rtes compred to blde tenderiztion. Implementtion of surfce intervention to beef subprimls, prior to further processing, would reduce the risk of pthogenic orgnisms being internlized, s well s reducing the risk of encountering foodborne illness from non-intct, blde tenderized or moisture enhnced beef products. For more informtion contct: Ntionl Cttlemen's Beef Assocition 9110 Est Nichols Avenue Centennil, Colordo 80112-3450 (303) 694-0305