Effect of lactic acid treatment during processing on the sensory quality and lactic acid content of fresh broiler chickens

Abstract

Microbial decontamination by lactic acid treatment during processing of fresh broiler chickens is an effective way to produce a safer product with good keeping quality. It remained to be assessed whether such a treatment adversely affects the organoleptic quality of the product. Lactic acid treatment results in an increased acid concentration in the skin, with no increase in lactic acid concentration in the underlying muscle tissue. Differences in sensory quality were only found in appearance of the carcasses, the controls being identified as discoloured. A preference test did not show any difference in lactic acid treated and untreated grilled legs.

Decontamination of chicken skin surfaces inoculated withListeria innocua,SalmonellaenteritidisandCampylobacter jejuniby contact with a concentrated lactic acid solution

“…These results differ from those of Van der Marel et al (1989), who observed a significant difference in residual concentrations between controls and upper leg skin treated for 15 s with a 2 or 5% solution of acid (1Á98 mg/g for the sample treated with 2% lactic acid against 1Á33 mg/g for the control). These differences may be due to the use of a specific measurement method inducing lower uncertainties, or a greater irregularity of the skin (splits, cracks, follicles) in this earlier work, causing a greater absorption of lactic acid.…”

“…No measurement of the coefficient of diffusion of lactic acid in skin could be found in the literature. However, after the treatment of upper legs with 5% lactic acid for 15 s and 3 d of storage, Van der Marel et al (1989) observed a significant increase in the lactic acid in the skin but not in underlying muscle, consistent with a slow diffusion of lactic acid in the skin. It might be useful to develop a diffusion model to predict residual values according to duration of treatment and concentration of decontaminant solution.…”

“…In addition, the diffusion of lactic acid through the skin is very slow. During treatment, Van der Marel et al (1989) observed no increase in lactic acid concentration in muscle even after 3 d of storage. The measurement of the residual concentration is necessary for better understanding of the persistence of the decontamination treatments and the possible organoleptic impact on the poultry product.…”

“…Studies that describe the effect of treatments on the organoleptic properties of chicken products reported no significant differences in taste, colour or acceptability of pieces (upper legs or drumsticks) cooked after treatment. A slight whitening of raw products was observed by Van der Marel et al, 1989;Okolocha and Ellerbroek, 2005;Gonzalez-Fandos and Dominguez, 2006). None of the treatments studied used more than 5% of lactic acid.…”

“…None of the treatments studied used more than 5% of lactic acid. In addition, residual lactic acid residues after treatment have rarely been measured ( Van der Marel et al, 1989). Normally, skin lactic acid concentrations are about 1Á33 mg/g just after slaughter, and 2Á4 mg/g after 3 d of storage.…”