Food Science & Human Nutrition
Non Technical Summary
Ready-to-eat food in U.S. retail settings raises numerous food-safety concerns, involving both the presence of foodborne disease organisms, and those organisms' tendency to cross-contaminate, e.g., pass from one food to another. Caused mostly by Listeria monocytogenes bacteria, listeriosis is the foodborne illness with the highest rates of hospitalization and mortality. Deli meats, deli salads, smoked seafood, and cheeses are the U.S.'s highest-risk foods per serving for this potentially fatal disease. In addition, Salmonella strains are commonly found in retail settings. This project will therefore investigate how well a microplasma-based far-UVC system - i.e., a lamp emitting ultraviolet (UV) light with a wavelength of 222 nanometers (nm) - inactivates the above-mentioned bacteria in liquid, on food-contact surfaces, and on deli meats. If it is effective, we will also look at the impact of this treatment on the products' quality, as measured by their color and lipid oxidation. Conventional UVC light, generally at 254 nm, is often used for decontamination, but can potentially lead to eye or skin damage, and is produced by lamps containing toxic mercury. Far-UVC light, on the other hand, does not damage mammalian cells (at the same dosages that do cause damage in the 254 nm case) and requires no mercury. These advantages could enable decontamination while workers and/or consumers are present. As such, the success of this project would provide affordable access to an easy-to-use engineered approach for minimizing cross-contamination and improving overall food safety.
Animal Health Component
Research Effort Categories
Goals / Objectives
The long-term goal of this project is to develop an inexpensive and easy-to-use decontamination technique with which stakeholders can minimize cross-contamination, and thus improve food safety. Its success will ultimately benefit the American people by increasing the availability and accessibility of safe and nutritious food. Our objectives on the way to achieving this goal are as follows:Objective 1: Evaluate the efficacy of microplasma-based far-UVC light for inactivating bacteria in buffer and on food-contact surfaces; Objective 2: Evaluate the efficacy of such far-UVC light for decontaminating real foods; and Objective 3: Evaluate the quality of foods with and without far-UVC light treatment.
Objective 1: Evaluate the efficacy of far-UVC light for inactivating bacteria in buffer and on food-contact surfaces. First, we will use a self-built far-UVC illumination system to investigate the bacterial-inactivation efficacy of far-UVC light when the target bacteria are in liquid buffer, and also measure microbial reactivation following treatment. We will evaluate the bacterial-inactivation efficacy of the far-UVC light system on both gram-positive bacteria such as Listeria monocytogenes and gram-negative ones such as Salmonella strains. Second, various food-contact surfaces (e.g., stainless steel) and common packaging materials (e.g., polyvinyl-chloride film) will be used to evaluate the efficacy of microplasma-based far-UVC light for decontaminating surfaces. An atomic-force spectroscopy and a goniometer will be used to characterize the surface roughness and hydrophobicity of each surface.Objective 2: Evaluate the efficacy of microplasma-based far-UVC light for decontaminating real foods. As compared to buffer and food-contact surfaces, most food is complex and varies in terms of moisture, composition, and texture; and packaging materials differ in terms of how much UV light will pass through them. All these factors may affect the bacterial-inactivation efficacy of far-UVC light. Thus, the primary tasks associated with this objective will include evaluating how well such light can decontaminate packaged and unpackaged real food products, using two of the most popular ready-to-eat deli products, i.e., ham and chicken breast.Objective 3: Evaluate the quality of foods with and without far-UVC light treatment. Color is one of the most important factors affecting consumers' pre-purchase perceptions of meat products. As well as causing color changes, lipid oxidation can negatively affect the quality of deli meats via the formation of rancid flavors and secondary oxidized compounds. Therefore, it is critical to ascertain whether bacteriologically effective dosages of far-UVC light will affect deli meats' color characteristics and lipid oxidation. The several top fluence values from Objective 2, in terms of their log-reduction performance, will be selected for treating the two target deli meats. Then, instrumental colors and lipid oxidation of the treated and untreated meats during storage will be ascertained using a colorimeter and a thiobarbituric acid-reactive substances assay, respectively.