|SEVART, NICHOLAS - Kansas State University|
|BAUMANN, NICOLAS - Kansas State University|
|THIPPAREDDI, HARSHAVARDHAN - University Of Georgia|
|HOUSER, TERRY - Kansas State University|
|MARX, DAVID - University Of Nebraska|
|ACUFF, GARY - Texas A&M University|
|PHEBUS, RANDALL - Kansas State University|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2016
Publication Date: 6/1/2016
Citation: Sevart, N., Baumann, N., Thippareddi, H., Houser, T.A., Luchansky, J.B., Porto Fett, A.C., Marx, D.B., Acuff, G.R., Phebus, R.K. 2016. Evaluating the efficacy of three USDA-approved antimicrobial sprays for reducing surrogate Shiga toxin-producing cells of "Escherichia coli on bob veal carcasses. Journal of Food Protection. 79(6):956-962.
Interpretive Summary: There are currently about 1,400 veal producers in the U.S., with most of these facilities being based in Indiana, Michigan, New York, Ohio, Pennsylvania, and Wisconsin. In 2005, it was estimated that the U.S. produced 150 million pounds of veal annually, with 71% of U.S. fine-dining, commercial foodservice operations using the product. Although E. coli and Salmonella spp. are occasionally associated with veal products, compared with other high-volume foods including beef, there have been far fewer recalls of veal products due to contamination with Shiga toxin-producing cells of E. coli (STEC) and these recent recalls of veal involved relatively small volumes of product and were responsible for only a handful of human illnesses. Regardless, commercial veal processors are implementing carcass intervention strategies to varying degrees to mitigate STEC issues. Yet, little research has been done to validate common antimicrobial technologies approved for use in beef processing for their effectiveness on decontaminating veal carcasses and/or the potential impact on the quality of the treated carcasses. The objective of this study was to validate the efficacy of readily-available and approved chemicals, namely lactic acid, Beefxide, and Citrilow, for reducing populations of non-pathogenic STEC surrogates on both hot and chilled bob veal carcasses, as well as to determine veal carcass color changes throughout the slaughter and chilling process that may result from such treatment. Our results showed that a final water wash (around 49 degrees C) provides an effective primary reduction step for controlling E. coli surrogates in veal processing. The application of an organic acid antimicrobial spray (i.e., lactic acid, Beefxide, and/or Citrilow) following a final water wash can serve as an additional processing step to help control STEC contamination. Our results also indicated that a second acid-based antimicrobial spray onto chilled veal surfaces does not provided any additional benefit in controlling STEC contamination. Further research must be done to evaluate effective antimicrobial sprays on chilled veal carcasses and fabricated products.
Technical Abstract: Shiga toxin-producing Escherichia coli (STEC) have recently been recognized as a problem for the veal industry, suggesting the need for effective antimicrobial intervention strategies throughout processing. Therefore, we evaluated the efficacy of lactic acid (4.5%), Citrilow™ (pH 1.2), and Beefxide® (2.5%) for reducing non-pathogenic STEC surrogates on pre-rigor and chilled bob veal carcasses, as well as monitored for any untoward consequences on carcass color. Veal calves were slaughtered using USDA approved practices and the de-hided carcasses were inoculated with a 5-strain mixture of rifampicin-resistant, surrogate E. coli bacteria. Levels of surrogate E. coli were determined after inoculation, final water wash, pre-chill antimicrobial spray, 24-h chill, and a second antimicrobial spray to chilled carcasses. Carcass color was measured using a Hunter MiniScan along the hip bone area at multiple processing points on pre-rigor and chilled veal carcasses. The final carcass water wash (approximately 120 degrees F) reduced the STEC surrogate population by 0.88 log CFU/cm2 (p = 0.05). All three antimicrobial sprays applied to non-chilled, pre-rigor carcasses showed an additional approximate 0.5 log reduction (p = 0.05) of surrogates. Chilling of carcasses for 24 hours reduced (p = 0.05) the surrogate population by an additional approximate 0.4 log cycles. The second application of the antimicrobial sprays after the 24-h chill period showed no further reductions. The carcass L* color values were not different among antimicrobials applied, but were different than the water-only control. The a* and b* values were not different among any of the treatments. Generally, visual color of chilled veal carcasses was not negatively impacted by the antimicrobial sprays evaluated. Findings from this study demonstrate that warm water washing followed by a final spray treatment with a low pH-based chemical intervention can effectively reduce STEC risks associated with veal carcasses if applied prior to carcass chilling without imparting any negative impacts on carcass color.