Progress 09/01/06 to 08/31/11
Outputs
OUTPUTS: It is common commercial process to inject fresh pork subprimal cuts with brine solutions to obtain a product with more consistent eating quality for consumer and an increasing profits and sale of branded product for the processor. However, enhancement can have negative effects on the microbiological quality of meat, for example, the numbers of spoilage and pathogenic bacteria counts increase during re-circulation of brine solutions. Perhaps more importantly, from a food safety perspective, the surface contaminated pathogens can be translocated into the center of the muscle, which was initially sterile. Concerns about the microbiological safety of such nonintact meats have been raised because consumers preparing dishes with these meats may regard them as intact product, for example, grilling without raising all deep tissues to temperatures that will certainly destroy pathogenic bacteria that may be present. Recently there has been a developing interest in the moisture enhancement by USDA-FSIS, in part due to the relative of information on the subject. Published data on the microbiological condition of the deep tissues of moisture enhanced pork products during production, distribution, consumption are few. There is also uncertainty about both the health risks that may be posed by pathogenic bacteria in the centre of meat and the temperature of cooking required to assure safety. Hence, the overall objective of this study was to evaluate the potential microbiological concern presented by moisture enhanced pork (1) translocation of bacteria from the surface into the interior of the meat (2) effects of moisture enhancement on survival of bacteria in meat during storage (3) impact of moisture enhancement on survival of food borne pathogens during cooking. Moisture enhanced pork may require assured control or additional protections, the second objective of this study was to evaluate the effectiveness of current interventions in reducing the occurrence and extent of food borne pathogens contamination on moisture enhanced pork. Methods and results were disseminated through publication of peer-reviewed papers, abstracts and on-line industry reports, and presentations at scientific meetings and to individual stakeholders. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: The target audiences of this project are food safety professionals in academic, industrial and governmental positions. In addition, the audiences include food producers and processors, distributors and food service opertaions. Perhaps most importantly, the target audience includes the consumer. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The translocation of bacteria from the surface into the interior muscle through moisture enhancement was studied in the first part of this research. The recovery of large numbers of E.coli biotype I from the deep tissues confirmed that bacteria were translocated from the surface into the depth of approximately 1 cm in the boneless pork following moisture enhancement.The number of inoculated E.coli biotype I recovered from the deep tissues after injection was not significantly affected (P>0.05) by the number on the surface of enhanced meat, moisture enhancement level and different locations in pork loins (approximately 6 cm from the leading edge, 6 cm from the trailing edge and in the approximate geometric center of the loin). In a second part of this research, the survival of Campylobacter jejuni and Salmonella enteric in moisture enhanced pork during vacuum storage was studied. There were no significant effect of moisture enhancement on the populations of Campylobacter jejuni and Salmonella enteric in samples (p>0.05).After 28 days, the populations of Campylobacter jejuni and Salmonella enteric in samples were significantly lower (p<0.05) than those of days 0. Mean populations of Campylobacter jejuni and Salmonella enteric in samples at 28th day were 4.24, 4.78 log10CFU/ml, respectively. No significant differences in Campylobacter jejuni counts were observed between samples at abuse temperature (10C) and those at refrigerated temperature (4C). In contrast, the population size of Salmonella enteric in samples at abuse temperature (10C) was significantly (p<0.05) higher than those at refrigerated temperature (4C). This study indicates that, vacuum packing under chilled conditions alone is not a substitute for safe handling and proper cooking. The event of temperature abuse during handling should be avoided. Finally, in a third part of this research, the survival of Campylobacter jejuni and Salmonella enteric in moisture enhanced pork, subjected to a heat treatment, conform to consumer-based grilling, was studied. Overall, Campylobacter jejuni cells were significantly less resistant than cells of Salmonella enterica. Higher internal temperature for cooking is more effective for completely bacterial inactivation. Significant interactions between storage temperatures and moisture were observed. The numbers of Campylobacter jejuni and Salmonella enteric in most of samples dropped below detectable with internal temperature of 160F, the USDA recommended 160F as the safe minimum internal temperature for intact pork maybe also adequate for assuring the microbiological safety of moisture enhanced pork that is prepared without excessive contamination of interior tissues. Compared to intact pork, moisture enhanced pork meat does not present a greater risk to consumers than otherwise similar meat that is intact, provided that the meat is properly cooked.
Publications
- No publications reported this period
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: The laboratory research has been completed, and all of the data necessary to develop the risk assessment has been collected (Objective 1, a through f). The risk assessment is currently being developed. Once completed, Objectives 3 and 4 will be readily completed. A mathematical model is being developed which will allow the researchers to run multiple simulations of the process, which will allow for the further evaluation of the process. This model is an essential piece in completing the final objectives. Methods and results were disseminated through publication of peer-reviewed papers, abstracts and on-line industry reports, and presentations at scientific meetings and to individual stakeholders. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In 2005, the United State is estimated to produce 20.5 billion pounds of pork (USDA-ERS, 2005). According to a 2004 nationwide retail survey (Anonymous, 2004), 45% of the retail fresh pork in the United States was labeled as "enhanced", with enhanced products defined as "moisture added and could also be value added (flavored and/or contained additional ingredients". Enhanced products are produced by passing meat through an injection machine, which forces needles into the product while simultaneously pumping a solution commonly containing salt, phosphates and other flavoring ingredients into the meat. This process has been extensively used for years with frozen turkeys and boneless chicken, but is now gaining popularity for red meat as well. In spite of the wide use of the process, relatively little information is available in the public domain regarding the microbiological safety of the process. Moisture enhanced products were identified as one of the four priority areas in the Post Harvest Food Safety program area in the National Pork Board's 2006 Research Solicitation. The results of the present research will result in the development of a model for the microbial safety of moisture enhanced pork products. This model will be used to identify which steps in the moisture enhanced process have the greatest impact on the overall safety of the product. Based on this output, additional process controls can be developed to minimize the risk associated with specific processing steps. Each step in the process of manufacturing moisture enhanced pork can contribute to the potential food safety risk. The computer model derived from the research date will allow the researchers to study the interactions between each step in the process, from initial contamination of the unprocessed pork through preparation by the consumer. A preliminary evaluation of the data indicates that the brine recirculation step and the final cooking by the consumer will have the greatest impact on the overall food safety risk.
Publications
- No publications reported this period
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Progress 09/01/07 to 08/31/08
Outputs
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 2. Develop a quantitative risk assessment of moisture enhanced pork. 3. Identify Critical Control Points in the moisture enhancement process, based on a sensitivity analysis of the quantitative risk assessment. 4. Develop educational materials to convey the results to both the industry and regulatory bodies. 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. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
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.
Publications
- No publications reported this period
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Progress 09/01/06 to 08/31/07
Outputs
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.
Impacts
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.
Publications
- No publications reported this period
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