Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/1/2010
Publication Date: 3/17/2011
Citation: Porto-Fett, A., Campano, S., Call, J.E., Shoyer, B.A., Yoder, L., Gartner, K., Tufft, L., Oser, A., Lee, J., Luchansky, J.B. 2011. Validation of food grade salts of organic acids as ingredients to control Listeria monocytogenes on pork scrapple during extended refrigerated storage. Journal of Food Protection. 74:394-402. Interpretive Summary: Scrapple is a ready-to-eat (RTE) loaf of meat/mush that is quite popular in the northeast quadrant of the United States, where it is especially enjoyed as a breakfast item. Although there have been no reported illnesses associated with pork scrapple and only a relatively small recall (ca. 350 pounds) due to contamination of scrapple with Listeria monocytogenes, we reported that scrapple provides a very favorable environment for growth of this pathogen. Although the pathogen is eliminated during cooking/processing, if present, it can be re-introduced onto the surface of scrapple if the finished product is exposed to the food processing environment prior to packaging and/or if after being opened the finished product is mishandled or left uncovered at retail or within a consumers refrigerator. Thus, the objective of this study was to evaluate the addition of food grade antimicrobials as ingredients to control L. monocytogenes over the expected 50 d refrigerated shelf life of pork scrapple. Antimicrobials tested included blends containing various concentrations of citrate, diaceate, propionate, levulinate, and lactate. Some of the antimicrobials tested in prefatory studies were excluded from further evaluation because of problems associated with solubility, issues with product texture/sensory attributes, and/or concerns about cost or availability. However, inclusion of a lactate-diacetate-propionate blend (1.94% and adjusted to pH 5.0) as an ingredient in pork scrapple suppressed pathogen outgrowth and appreciably extended shelf life without causing untoward effects on quality. Future studies will be directed to tailor this blend for applications in other foods to lower the chances of consumers acquiring food borne listeriosis.
Technical Abstract: Pork scrapple was formulated, with or without citrate-diacetate (0.64%), by a commercial processor to contain various solutions/blends of the following antimicrobials to control L. monocytogenes on pork scrapple during refrigerated storage: i) lactate-diacetate (3.0 or 4.0%), ii) lactate-diacetate-propionate (2.0 or 2.5%), and iii) levulinate (2.0 or 2.5%). Regardless of whether or not citrate-diacetate was included in the formulation, without the subsequent addition of the targeted antimicrobials, pathogen levels increased ca. 6.4 log CFU/g within 50 d of storage. In the absence of citrate-diacetate, but with the inclusion of the targeted antimicrobials in the formulation, pathogen numbers increased by ca. 1.3 to 5.2 log CFU/g, whereas with citrate-diacetate in combination with these antimicrobials pathogen numbers increased by ca. 0.7 to 2.3 log CFU/g. In phase II, in the absence of citrate-diacetate, when the pH of the lactate-diacetate-propionate blend was adjusted to pH 5.0 or 5.5, pathogen numbers increased by ca. < 0.5 log CFU/g, whereas with inclusion of citrate-diacetate in combination with the blend adjusted to pH 5.0 or 5.5, pathogen numbers decreased by > 0.3 log CFU/g. In phase III, inclusion of lower concentrations of this blend (1.5%, 1.94%, or 2.5%) with its pH adjusted to pH 5.5, pathogen numbers increased by ca. 0.6 and 4.7, and 0.56 log CFU/g, respectively, whereas when pH of the blend was adjusted to pH 5.0, pathogen numbers increased by < 0.62 log CFU/g. Inclusion of a lactate-diacetate-propionate blend ingredient in the scrapple formulation provides a less favorable environment for outgrowth of L. monocytogenes over the 50 d shelf life in an event of post processing contamination.