Evaluation of frankfurters formulated with potassium lactate and sodium diacetate and innocualted with Listeria monocytogenes before and after irradiation treatment
Microbial safety and quality attributes were evaluated for frankfurters formulated
with potassium lactate/sodium diacetate (0 or 3%) and inoculated with a four-strain
Listeria monocytogenes cocktail before and after treatment with pasteurizing doses of
irradiation (0, 1.8, or 2.6 kGy). Frankfurters were inoculated after irradiation and stored
aerobically for 4 wk at 4 Â°C to simulate the product becoming contaminated after
opening, or they were inoculated prior to vacuum packaging and stored for 8 wk at 4 Â°C.
Incorporation of lactate/diacetate into frankfurter formulations with or without
irradiation had a strong listeriostatic effect throughout 4 wk of aerobic storage. Total
microbial counts for frankfurters formulated with lactate/diacetate remained constant
throughout storage while those without increased steadily (5.4 to 9.3 log cfu). Over 4 wk
of storage, the outgrowth of L. monocytogenes on frankfurters formulated with
lactate/diacetate was effectively suppressed and counts were not significantly different
from initial counts (5.2 vs. 5.0 log cfu, respectively). Irradiation treatments alone had
significantly higher L. monocytogenes counts after 3 wk of storage. Both treatments together or alone were not detrimental to sensory aroma or flavor attributes.
Meaty/brothy complex, smoke, spice aroma, springiness, and cohesiveness attributes
were judged slightly lower for frankfurters formulated without lactate/diacetate than
those with lactate/diacetate at the end of aerobic storage. Sensory color was not
dramatically influenced by either treatment, however, L*a*b* values of all treatments
decreased slightly during storage.
Both the addition of lactate/diacetate to a frankfurter formulation and irradiation
were effective towards controlling microbial growth of L. monocytogenes in an
unopened vacuum package after 8 wk of storage. Large and incremental reductions in
total microbial counts were seen with irradiation treatment, which were maintained
throughout storage with lactate/diacetate treated frankfurters. There were fewer
influences on sensory characteristics for vacuum packaged frankfurters compared to
those aerobically packaged.
Overall, lactate/diacetate addition and irradiation to a lesser extent were effective
towards retarding the outgrowth L. monocytogenes on frankfurters while maintaining
quality attributes throughout aerobic storage. The combination of irradiation and
lactate/diacetate were effective for reducing and retarding growth of L. monocytogenes
and especially during the last two weeks of vacuum packaged storage.
Advisor:Keeton, Jimmy; Castillo, Alejandro; Cisneros, Luis; Miller, Rhonda
School:Texas A&M University
School Location:USA - Texas
Source Type:Master's Thesis
Date of Publication:05/01/2003