Effects of combined organic acid treatments during the cutting process on the natural microflora and quality of chicken drumsticks

Improved microbial and sensory quality of chicken meat by treatment with lactic acid, organic acid salts and modified atmosphere packaging

Microbial contamination and growth play important roles in spoilage and quality loss of raw poultry products. We evaluated the suitability of three commercially available organic acid based antimicrobial compounds, Purac FCC80 (l-lactic acid), Verdad N6 (buffered vinegar fermentate) and Provian K (blend of potassium acetate and diacetate) to prevent growth of the innate microbiota, reduce spoilage and enhance the sensory quality of raw chicken under vacuum, high CO₂ (60/40% CO₂/N₂), and high O₂ (75/25% O₂/CO₂) modified atmosphere (MA) storage conditions. Solutions were applied warm (50 °C) or cold (4 °C) to reflect treatments prior to (Prechill) or after (Postchill) cooling of chicken carcasses, respectively. Single postchill treatments of raw chicken wings with 5% Verdad N6 or Provian K solutions and MA storage enabled complete growth inhibition during the first seven days of storage before growth resumed. Enhanced bacterial control was obtained by combining Prechill lactic acid and Postchill Verdad N6 or Provian K treatments which indicated initial reductions up to 1.1 log and where total bacterial increase after 20 days storage was limited to 1.8-2.1 log. Antibacterial effects were dependent on the concentration of the inhibiting salts used, pH and the storage conditions. Bacterial community analyses showed increased relative levels of Gram-positive bacteria and with reductions of potential spoilage organisms in samples treated with the organic acid salts Verdad N6 and Provian K. Sensory analyses of raw, treated wings showed prominent lower scores in several spoilage associated odour attributes when compared with untreated chicken wings after 13 days storage. For heat-treated chicken, only minor differences for 22 tested attributes were detected between seven antimicrobial treatments and untreated control chicken. Immersion in commercially available organic acid/salt solutions combined with MA storage can reduce bacterial levels, improve microbial and sensory quality, and potentially improve shelf life and reduce food waste of chicken products.

Effects of lactic, malic and fumaric acids on Salmonella spp. counts and on chicken meat quality and sensory characteristics

The aim of this work was to assess the effectiveness of dipping chicken breast in lactic, malic and fumaric acid 3% solutions for 15 s on Salmonella counts, as well as on chicken meat quality and sensory characteristics. All three treatments effectively reduced Salmonella counts. The values of Salmonella log reduction were 2.22, 1.55 and 1.30 log CFU/g for fumaric, malic and lactic treatments, respectively. Although fumaric acid was the most effective for reducing Salmonella counts, chicken meat quality and sensory characteristics were significantly affected, even in cooked samples. Conversely, malic and lactic acids treatments caused minimal changes in chicken meat quality and sensory characteristics compared to control samples. This study shows effective alternatives to reduce Salmonella contamination on chicken breast fillets, although further studies should be considered to improve the effects on quality and sensory attributes.

Efficacy of combinations of lactic acid and potassium sorbate against Listeria monocytogenes in chicken stored under modified atmospheres

The combined effect of lactic acid and potassium sorbate on the growth of L. monocytogenes on chicken legs packaged under modified atmospheres (MAP) and stored at 4 °C was evaluated. An extended lag phase and a lower maximum growth rate for psychrotrophs and mesophiles was found in those samples packaged in 20%CO₂/80%N₂ and washed with different combinations of lactic acid and potassium sorbate compared to those non-treated with organic acids. Legs packaged in 20%CO₂/80%N₂ and washed with 3.75% lactic acid- 3.75% potassium sorbate showed a significant (p < 0.05) reduction in L. monocytogenes compared to untreated chicken legs packaged in MAP, which were approximately 2.63 log units lower in the first ones after 8 days of storage. Moreover, this treatment was the most effective in decreasing the maximum growth rate of L. monocytogenes. The chicken legs packaged in atmospheres containing 20%CO₂/80%N₂, had an extended shelf life, but these atmospheres were not able to reduce L. monocytogenes, thus underlining the need for preventive measures so as to control this pathogen. The immersion of chicken legs in a solution containing 3.75% lactic acid- 3.75% potassium sorbate can reduce L monocytogenes populations on fresh chicken packaged in a modified atmosphere.

In vitro and in situ inhibition of some food-borne pathogens by essential oils from date palm (Phoenix dactylifera L.) spathe

Essential oils extracted by hydro-distillation form date palm spathe (byproduct from date palm plants) were tested for their antibacterial activity against some food-borne pathogens. Listeria monocytogenes ATCC 7644, Staphylococcus aureus ATCC 29243, Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076 and E. coli ATCC 25922 were inhibited (11-13 mm inhibition zones) by spathe essential oils (SEOs) using the agar well assay (in vitro test). Staphylococcus aureus ATCC 29243 and E. coli ATCC 25922 were not detected in chicken meat treated with 1% (v/w) SEOs and subjected to abusive storage conditions (20 °C for 18 h). When treated with 0.5% SEO, counts of S. aureus and E. coli increased by only 0.2 and 0.7 log₁₀ cfu/g, respectively, compared to the initial inoculated level in meat samples stored at 20 °C for 18 h. SEOs possessed DPPH radical scavenging activity with IC₅₀ of 0.61 μg/ml. Forty one compounds were major constituents detected by GC-MS analysis of SEOs. 3,4-Dimethoxytoluene (38.12%) and 5,9-Undecadien-2-one (12.45%) were major compounds in extracted oils. Density and refractive index of SEOs were 0.987 and 1.5905, respectively. SOEs are added-value products from date palm, which could be employed in food industry and pharmaceuticals. The study is the first report on antibacterial activity of SEOs against L. monocytogenes ATCC 7644 and other standard food-borne pathogens in agar diffusion assay and food model (chicken meat). DPPH radical scavenging activity of SEOs has not previously been documented.

The Use of Malic and Acetic Acids in Washing Solution to Control Salmonella spp. on Chicken Breast

Salmonella is a persisting contaminant in poultry products that may pose a potential risk to consumers. Thus, developing decontamination strategies to eliminate or reduce this pathogen in chicken is crucial. The objective of the current study was to investigate the antimicrobial activity of malic acid (MA) and acetic acid (AA) or their combination against Salmonella on chicken breast at 4 °C for 10 days. The effect of storage temperature (4 and 21 °C) on Salmonella inactivation was also investigated for up to 21 days. Five serovars of Salmonella were inoculated in a model Mueller-Hinton (MH) broth system to a level of about 7 log₁₀ CFU/mL and the broth was treated with 5 mg/mL of each of MA, AA or their combination. AA was more effective than MA in the model system at 21 °C, where it resulted in total elimination of Salmonella, but MA was more effective in eliminating Salmonella at 4 °C. However, the combined MA and AA solutions were more effective than either MA or AA alone. When applying washing solutions containing 5 mg/mL of either of MA, AA, or their combination to chicken breast inoculated with about 5 log₁₀ CFU/g, the MA+AA washing solution was the most effective. It resulted in complete elimination of Salmonella from chicken breast and rendered a significant reduction in mesophilic aerobic bacteria and lactic acid bacteria numbers.

PRACTICAL APPLICATION

This study indicates that the use of a washing solution containing MA and AA could improve the safety and extend the shelf life of raw chicken by substantially reducing Salmonella and contaminating microflora on the product.