Validation of Levulinic Acid for Topical Decontamination of Meat Surfaces

This project assessed if levulinic acid, as a topical treatment, was effective against pathogenic bacteria. It evaluated whether topical application imparts residual protection against pathogen growth. This research was a follow up to previous research on the anti-listerial action of levulinate.

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Objectives

1.  Investigate the reduction of pathogenic bacteria inoculated onto meat surfaces that results from washing with water and organic acids (2% lactic, acetic, or levulinic).

2.  Look at the reduction of E. coli O157:H7 inoculated on beef plate that results from washing with levulinic acid at various concentrations and temperatures.

3.  Study the residual protection against growth of pathogenic bacteria inoculated on meat surfaces previously washed with water and organic acids.

4.  Evaluate the organoleptic implications from spraying slices of turkey roll or beef trim with water and organic acids.

Conclusions

1.  Acid washes did not reduce numbers of E. coli O157:H7 or L. monocytogenes on beef plate and turkey roll slices, respectively   Acid washes reduced numbers of Salmonella on pork belly and chicken skin by about 1 log/sq cm, but the effect was no more than attained using only a water wash.

2. Washing with 2% levulinic acid did not reduce numbers of E. coli O157:H7 on beef plate even when applied at elevated temperatures.

3. Washing with the organic acids did not provide residual protection against growth of E. coli O157:H7 and L. monocytogenes.  Only acetic acid protected against growth of Salmonella, and only on chicken skin.       

4. Spraying slices of turkey roll and beef trim with 2% lactic, acetic, or levulinic acid did not impact consumers’ overall liking of the turkey roll or cooked patties, respectively.  There were some small effects on instrumental measures of color, but these appeared to be of little practical significance.

Deliverable

Washing with organic acids was no more effective than water at reducing numbers of pathogenic bacteria on meat surfaces regardless of organic acid, bacterial species, or meat tissue type.  Thus, it was not possible to establish the potential for levulinic acid as a substitute for lactic and acetic acids employed for surface decontamination of meat.  This may be related to the 2% concentration of acids used in this research that was chosen based on industry practice at the time our proposal was submitted.  It is interesting to note that the meat industry has since gone to using lactic and acetic acids at higher concentrations.  However, we cannot find a sound validation for their use at concentrations greater than 2%.