Moisture Enhanced Pork - Development of a Quantitative Risk Assessment

NON-TECHNICAL SUMMARY: The process of injecting water, salt and other flavoring agents into meats has been well developed in both poultry and pork. Currently, approximately 45% of the pork available to the consumer at retail has been "moisture enhanced" to various degrees. Relatively little data exists in the public domain on the microbiological safety of the product and the quality of the process with pork. While the process is similar in some respects to mechanical tenderization of beef, there are sufficient differences to warrant further investigation. We propose to study the microbiology of the process of moisture enhancement of pork from a quantitative standpoint, and use this data to develop a quantitative risk assessment.

<P>
APPROACH: We propose to study the microbiology of the process of moisture enhancement of pork from a quantitative standpoint, and use this data to develop a quantitative risk assessment. For the purposes of this proposal, we will define the process as beginning with the moisture enhancement of the raw pork through the final cooking prior to consumption. The output (risk) will be the probability of a consumer receiving a serving of pork contaminated with either salmonellae or Campylobacter spp. A sensitivity analysis of each process within the risk assessment will allow us to determine critical control points and to establish critical limits for the process. Once these have been established, a presentation will be developed for both in class and distance education which identifies all of the steps in the process and illustrates both the CCP and monitoring for the critical limits. In addition, a full presentation of the experimental data, development of the risk assessment model, and the technical papers will be published as a CD to be made available to trade associations and processors.

<P>

PROGRESS: 2007/09 TO 2008/08<BR>
OUTPUTS: The specific objectives of the project were 1. Evaluate the potential microbiological concerns with moisture enhanced pork. (a) transfer of bacteria from the surface into the interior of the meat. (b) potential cross contamination by the injector needles. (c) effect of pump volume on bacterial contamination. (d) potential survival of bacteria in re-circulating brine. (e) effects of moisture enhancement on survival of bacteria in meat during storage. (f) impact of moisture enhancement on survival of food borne pathogens during cooking <BR> 2. Develop a quantitative risk assessment of moisture enhanced pork. <BR> 3. Identify Critical Control Points in the moisture enhancement process, based on a sensitivity analysis of the quantitative risk assessment. <BR> 4. Develop educational materials to convey the results to both the industry and regulatory bodies. <BR> <BR> Objectives 1a to 1e have been completed, while objective 1f should be completed by the end of calendar year 2008. The results indicate that bacterial pathogens may be transferred from the surface into the center of the meat. The level of transfer is affected by the population and distribution on the surface of the meat. If a contaminated piece of meat is processed through the injector, subsequent pieces may become contaminated. While somewhat inconclusive, the volume of liquid pumped into the meat does not seem to affect the rate of contamination. Pathogenic bacteria which contaminate the brine may survive for up to 48 hours, depending on the initial population of contamination. Although the study is incomplete at this time, the preliminary results have been informally conveyed to the meat industry in various ways, including summary reports and informal discussions. <BR> <BR>

IMPACT: 2007/09 TO 2008/08<BR>
The major outcome of the project, the risk assessment and identification of critical control points, has yet to be completed. When completed, these will provide significant information to the industry to help them better understand the process and the areas which are necessary for control. This will benefit the industry by allowing them to specifically focus their efforts on the areas which have the greatest impact on the safety of the product. Risk assessment is a synthesis project, where multiple data sets are combined to evaluate the interactions and potential outcomes. The results to date reflect current knowledge of the moisture enhanced process, although the survival of salmonella and Campylobacter in the brine solutions is novel information. The degree of transfer from the surface to the interior was larger than expected, as was the potential for cross contamination of the re-circulating brine.
<BR> <BR>
PROGRESS: 2006/09/01 TO 2007/08/31<BR>
A single pork loin was inoculated with a five strain mixture of non-pathogenic E. coli bacteria. The loin was moisture enhanced with an injection level of 10%. After the inoculated loin was moisture enhanced, four more non-inoculated loins were moisture enhanced. Microbiological analysis of both the exterior and interior indicated that the non-inoculated loins were readily contaminated by both the brine and injection equipment, after the inoculated loin was injected. Further analysis indicated that both the brine and needles were contaminated, and that this contamination was likely the source of the subsequent cross contamination. After injecting the first pork loin, 1 - 2 log cycles of E. coli were recovered per needle, while the population in the re-circulating brine was approximately 4.6 log cfu/50 ml. A 5 strain mixture of Salmonella enterica was inoculated into a re-circulating brine system at 4C, and the population monitored over 48 hours. The bacterial population declined approximately 1.5 log cycles within 8 hours, and a total of 2 log cycles over 48 hours.
<BR> <BR>
IMPACT: 2006/09/01 TO 2007/08/31<BR>
The process of injecting water, salt and other flavoring agents into meats has been well developed in both poultry and pork. Currently, approximately 45% of the pork available to the consumer at retail has been "moisture enhanced" to various degrees. The results of this research will lead directly to the development of a risk assessment to predict the probability of a consumer receiving a contaminated serving of pork under various conditions. A sensitivity analysis of the risk assessment nodes will determine which steps in the process are essential for reducing the risk to the consumer. Based on this information, specific guidelines will be developed for the food industry to recommend mechanisms for controlling the critical processing steps, from both an operational and monitoring standpoint. The end result will be a better understanding of the microbiology of this process, along with practical industry guidelines for assuring the safety of the product.