A Novel Strategy for Reducing Salmonella Enteritidis Cross-Contamination in Ground Chicken Meat Using Thymol Nanoemulsion Incorporated in Chitosan Coatings

This study evaluated the capability of a thymol nanoemulsion (nTHY) to reduce cross-contamination with Salmonella Enteritidis in ground chicken meat. First, an nTHY ( 54 nm) was prepared in a high-shear speed system (rotor–stator) and proved stable, remaining below 100 nm for 30 days in storage at 4 °C. Then, a minimum inhibitory concentration assay was performed by combining S. Enteritidis with viable native bacteria from chicken meat. nTHY presented half the MIC that was observed for its non-nanoemulsified versions for Salmonella Enteritidis (MIC = 0.31 mg/mL) and combined with native chicken bacteria (MIC = 0.625 mg/mL). A chitosan (CH) coating containing nTHY (6 mg/mL), equivalent to 10 × MIC (S. Enteritidis + native chicken bacteria), was prepared for in situ evaluation. Two groups of distinct chicken fillets were prepared for cross-contamination during grinding: chicken fillets experimentally contaminated with S. Enteritidis ( 6.5 log CFU/g) and chicken fillets without S. Enteritidis but with the applied treatments (control, coated with CH, nTHY, and CH + nTHY). nTHY showed a bacteriostatic effect throughout the 7 days of storage. The CH + nTHY coating was the best treatment applied, reducing cross-contamination by up to 1.91 log CFU/g compared to uncoated samples. Thymol nanoemulsions can be natural alternatives to guarantee the microbiological safety of meat and meat products.