Investigation of food safety parameters for fermented semi-dry and dry sausage products
Open Access
- Author:
- Mckinney, Samantha Rene
- Graduate Program:
- Animal Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 23, 2017
- Committee Members:
- Jonathan Campbell, Thesis Advisor/Co-Advisor
Catherine Cutter, Committee Member
Nancy Ostiguy, Committee Member - Keywords:
- E. coli O157:H7
Salmonella
L. monocytogenes
fermented sausages - Abstract:
- Fermentation and drying are two methods utilized by humans for thousands of years to preserve food. Fermented semi-dry and dry sausages are safe, ready-to-eat (RTE) meat items produced using strict government regulations. One of these regulations requires meat processing establishments to create and have a scientifically-validated Hazard Analysis Critical Control Point (HACCP) plan. HACCP plans are validated utilizing a combination of data collected in the plant and scientific literature to ensure that process controls exist for identified food safety hazards. When little or incomplete data exists for very specific products or processes, challenge studies may be conducted to investigate the safety of the processes used to produce the food item. Three experiments were conducted to determine the effects of varying fermented semi-dry and dry sausage production parameters on the reduction of three pathogenic bacteria: E. coli O157:H7 (EC), Salmonella spp. (S; S. Typhimurium, S. Montevideo, and S. Panama), and L. monocytogenes (LM). These experiments will serve as challenge studies for semi-dry and dry sausages under various conditions. The first experiment evaluated the effects of fat content and grind size on the attachment and survival of pathogenic bacteria in fully-cooked, semi-dry sausages. Lean and fat trim consisting of beef and pork were analyzed for fat content and mixed to create meat blocks consisting of 10%, 20%, and 30% fat. Meat blocks were ground a second time to create meat particles that were 3.00 mm, 4.75 mm, or 12.50 mm in size. Neither fat content nor grind size significantly impacted pathogen populations for any of the bacteria examined (p>0.05). A second experiment demonstrated the efficacy of a low-heat treatment for an extended time to reduce pathogenic bacteria in a fermented, dry sausage. Ground pork (20% fat) was stuffed into 38-mm, 64-mm, and 120-mm diameter casings, fermented, heat treated, dried, and vacuum-packaged up to 28 d. A 5 log10 reduction was achieved by day 9 (D9) of drying for S and LM regardless of diameter; by D16 of drying, EC was reduced by 5 log10 CFU/g for all diameters. Significant differences were observed among casing diameters for S. The third experiment demonstrated no difference among casing type or pork trim sprayed with tap water or an antimicrobial prior to grinding in a non-heat treated, dry salami (p>0.05). Pork trim was treated with either tap water or a 2.5% Beefxide spray prior to grinding. The ground pork was stuffed into three casings (natural, collagen, and fibrous), fermented and dried. There was no significant difference between the control and treated sausages for the reduction of EC (p=0.1645), S (p=0.3746), or LM (p=0.1762). There was also no significant difference between casing types within each sausage treatment. A 5 log10 reduction was achieved for S and LM by the end of vacuum packaging (up to 28 d), but EC was not reduced by a 5 log10 reduction by the end of vacuum packaging. EC was reduced by a maximum 4.02 log10 CFU/g in the collagen sausage when treated with the antimicrobial. These experiments may be utilized by processors as supporting documentation in HACCP plans, as well as be accepted by the United States Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) personnel as validation and scientific evidence for use in HACCP plans.