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Elimination and Control of Pathogenic and Spoilage Microorganisms by Emerging Processes

Knabel, Stephen; Demirci, Ali
Pennsylvania State University
Start date
End date
The overarching goal of this reserach is to develop novel economical processes in order to elimination and control of pathogenic and spoilage microorganisms. The specific objectives leading to this goal are to further:
  1. Application and optimization of emerging non-thermal and thermal processes for inactivation and control of pathogenic bacteria in foods;
  2. Low-cost production of antimicrobials and other value added products via microbial fermentation;
  3. Mathematical modeling for scale-up purposes.
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NON-TECHNICAL SUMMARY: Foodborne pathogenic and spoilage microorganisms cause serious healt and economical problems. The purpose of this project is elimination and control of pathogenic and spoilage microorganisms by emerging processes.

Objective 1-- Irradiation process will be optimized for meat with application of antimicrobials. Supercritical carbon dioxide will be used to decontaminate sprouting seeds. Ozonation and electrolyzed oxidizing water will be used to decontaminate fruits, vegetables, and processing equipments. Novel thermal processes will be evaluated for the effectiveness of inactivation of food microorganims.

Objective 2-- Production costs of antibiotics and organic acids as antimicrobials will be lowered by (1) increasing biomass concentration in the fermentation medium by means of biofilm/immobilized cells which yield high product concentrations in batch, fed-batch, or continuous fermentation, (2) novel separation/purification methods, and (3) utilization of low cost by-products or wastes from food processing as fermentation media.

Objective 3-- Based on data collected in Objectives 1 and 2, an attempt will be made to develop a mathematical modeling for each process which provide a useful tool for quick and reliable prediction for the process, and scale up for industrial applications.

PROGRESS: 2000/08 TO 2005/06
The following projects have been undertaken between 2000 and 2005:
1) Ozonation for decontamination of alfalfa seeds and sprouts.
2) Pulsed UV-light treatment for decontamination of pathogenic microorganisms on alfalfa seeds;
3) Electrolyzed oxidizing (EO) water treatment for decontamination of alfalfa seeds and sprouts;
4) EO water for decontamination of fresh poultry carcasses, and ready-to-eat foods and compared with common sanitizing agents;
5) Supercritical carbon dioxide treatment for decontamination of alfalfa seeds;
6) Ozone and EO water for inactivation of yeast in fermentation broth;
7) Laboratory-scale physical and chemical treatment systems for vacuum pretreatment followed by treatment with aqueous or gaseous anti-microbial solutions;
8) Pilot-scale unit operation for treating contaminated produce by submerging in an elevated temperature aqueous antimicrobial solution;
9) A pathogen containment, which allowed pilot-scale unit operations to be tested with human pathogen-inoculated produce;
10) Effect of polylactic acid plastic on inactivation of pathogenic microorganisms on meat during irradiation and compared with common plastic materials;
11) Evaluation of Cleaning-In-Place (CIP) of farm milking systems with acidic and basic EO water;
12) Optimization of food waste composting for inactivation of pathogenic microorganisms during in-vessel and windrow composting;
13) Nisin fermentation was optimized for biofilm reactors;
14) Evaluation of EO water for egg washing to decontaminate Salmonella Enteritidis and E. coli;
15) Evaluation of EO water to control microorganisms on mushroom by using EO water during irrigation;
16) Pulsed-UV light technology for inactivation of Clostridium sporogenes in honey;
17) Pulsed UV-light treatment of corn meal for inactivation of Aspergillus niger;
18) Inactivation of Staphylococcus aureus in buffer and milk by using pulsed UV-light and infrared heating;
19) Development of dynamic computational model for Listeria monocytogenes growth in cheese was conducted;
20) Development of segmented-flow system which allows foods with or without particles to be aseptically processed;
21) EO water, pulsed UV, and ozone for decontamination of raw fish;
22) Control of patulin in apples and apple products by inactivating Penicillium species with EO water, pulsed UV, and ozone;
23) Evaluation of pulsed UV light for decontamination of apple cider and orange juice as a static system;
24) Recovery of Listeria monocytogenes following high pressure processing of milk;
25) Nisin fermentation by using immobilized cell fermentation;
26) Decontamination of small fruits by gaseous ozone;
27) Development of continuous steam sterilization unit capable of producing shelf-stable aseptically processed particulate foods of high quality;
28) Determination of the kinetics of injury and inactivation of Listeria monocytogenes during high pressure processing and the mechanisms by which this pathogen recovers from injury following high pressure processing.

IMPACT: 2000/08 TO 2005/06
It has been estimated by The Centers for Disease Control and Prevention (CDC) that food-borne outbreaks may cause 76 million illnesses and 5,000 deaths in the United States every year. Also, the CDC reported that the number of known cases of food-borne illnesses has increased more than five-fold since 1942. Treatment cost is about $8.4 billion annually in medical expenses. Therefore, efforts for decreasing food-borne diseases have been tremendously increased in the last decade. This project is investigating emerging technologies to eliminate and control of pathogenic and spoilage microorganisms during food processing and storage to prevent possible outbreaks and improve the quality of the foods. Utilization of antimicrobials for prevention purposes is getting attention, but their high cost is a limiting factor. Therefore, this project is attempting to enhance production of some antimicrobials via microbial fermentation in order to reduce production cost. The outcome of this project will benefits farmers, food processors, trade associations and most importantly public as the end users.

Funding Source
Nat'l. Inst. of Food and Agriculture
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Bacterial Pathogens
Natural Toxins