Reduction or Inhibition of Bacterial Foodborne Pathogens on Fresh and/or Processed Muscle Foods

NON-TECHNICAL SUMMARY: A. Antimicrobials, antimicrobial packaging, or novel interventions may improve the safety and quality of meat. B. Understanding bacterial attachment is important to prevent attachment or detach bacteria from meat. 1. This project examines the development and validation of packages containing antimicrobials to reduce bacteria on meat. 2&4. These projects identify and validate novel antimicrobials or interventions to improve the safety of meat. 3. This project examines bacterial attachment and develops better ways to detach bacteria.<P>

APPROACH: 1. The incorporation of antimicrobial compounds into heat-extruded plastics and edible films has been found to retain activity and reduce spoilage and pathogenic bacteria on fresh meat and poultry surfaces. The incorporation of antimicrobials, in combination with other food grade compounds, into edible or plastic films may provide a means of controlling the growth of pathogenic and/or spoilage organisms, thereby enhancing the microbial quality and safety of a variety of fresh or processed muscle foods. Non edible and edible films will be developed that incorporate the antimicrobial of interest (nisin, colicin, lysozyme, etc.) to effect the greatest activity. Films will be evaluated alone and/or in combination with other food grade compounds (organic acids, EDTA, phosphates, etc.) to inhibit foodborne bacteria in plate overlay assays as well as in meat experiments. 2. While there are several USDA-approved antimicrobials capable of inhibiting pathogens on or in fresh or processed meat, poultry, seafood, or fish, there is sufficient interest in identifying new or novel antimicrobial compounds, alone or in combination with other existing technologies. There is also interest in utilizing compounds that do not adversely affect the environment, have GRAS or "natural" status, and are inexpensive. Such technologies could offer meat processors improvements to the microbiological safety of their products while also minimizing costs. Plate overlay assays will be used to screen these selected compounds against the target pathogens as well as determine concentration(s) to use for subsequent meat experiments. 3. Very little information has addressed the use of Confocal Scanning Laser Microscopy (CSLM) for determining depth of penetration, detection, enumeration, or mechanisms of bacterial attachment to the surfaces of muscle foods or processed meats in real time. The high resolution, virtually artifact-free, 3-D images of CSLM taken from unaltered samples could provide researchers with a better understanding of the mechanisms of bacterial attachment of pathogenic or spoilage bacteria to meat components. A better understanding of the mechanisms affecting bacterial attachment will be useful in devising techniques to prevent attachment or detach pathogenic and spoilage bacteria from fresh and processed muscle foods. 4. Thorough literature searches will be conducted to identify novel or potential interventions for pathogen reduction or inhibition in vitro and in situ (meat or poultry), applied alone or in combination with existing technologies. Interventions will be selected that can be transferred to pilot plant conditions for validation under controlled experimental conditions. Such technologies will be evaluated for practicality, effectiveness, and transferability to current meat industry practices. Technologies may include, but are not limited to, blast or rapid chilling, pulsed electric fields, pulsed light, hydrostatic pressure, electrolyzed oxidizing water, etc.

<P>

PROGRESS: 2000/08 TO 2005/06<BR>
The control of microbial contamination of meat and poultry products should begin during slaughter operations and continue through fabrication and further processing. If overall microbial contamination can be reduced or eliminated at any step in the process, the incidence of pathogenic bacteria moving into the food supply will be reduced. Using this approach, studies have demonstrated that the safety and quality of fresh and further processed muscle food products (meat, poultry) can be improved significantly by a number of methods. Because bacon is not a thoroughly cooked product, Listeria monocytogenes may survive the curing and smoking process and cross contaminate ready-to-eat (RTE) meats that are packaged in the same area. Studies demonstrated that the individual and combined effects of bacon processing reduced levels of Listeria spp. and L. monocytogenes significantly. Under laboratory and commercial processing conditions, snap/blast or commercial chilling significantly reduced foodborne pathogens associated with pork carcasses. In another study, swab samples taken from pork refrigeration units indicated that rails, overhead structures, and condensate droplets may be sources of pathogens in pork processing, but the incidence is low. Additional experiments demonstrated the stability of electrolyzed oxidizing water under different laboratory conditions and the ability of the compound to reduce foodborne pathogens in cell suspensions, on pork surfaces, poultry carcasses, and to a lesser degree, RTE meat and poultry products. Another study demonstrated that an acid phosphatase assay (ACP) assay verified adequate thermal processing of several precooked seafood products (crab, shrimp, lobster), but implicated undercooked clams in a foodborne illness outbreak. Other experimental results also demonstrated that the addition of sodium lactate/acetate enhanced destruction of foodborne pathogens in a variety of cooked meat products, such that the final internal product temperature of meat products could be reduced to save cooking time, thermal energy, and minimize product weight loss. Several studies also were conducted to evaluate the sensory and microbial changes of RTE products subjected to a post-packaging heat treatment, as well as the implementation and acceptance of the technology by very small meat and poultry processors. Results indicated that L. monocytogenes was reduced significantly on most products immediately following a post- packaging heat treatment and during refrigerated storage. While consumers found the taste and texture of RTE products to be acceptable, the ring bologna or snack sticks were not visually acceptable. Three of four RTE processors who implemented the technology and evaluated their products did not find the products to be acceptable. This comprehensive study demonstrated the importance of investigating quality attributes and acceptance criteria in addition to implementation of food safety measures.
<BR> <BR>
IMPACT: 2000/08 TO 2005/06<BR>
The goal of these projects was to provide meat and poultry processors with the necessary methodologies to improve the microbiological safety and quality of their products. It is hypothesized that these technologies, if implemented by meat and poultry processors, would result in an overall decrease in foodborne illness and product recalls.