Lactic acid bacteria as a biocontrol agent for the reduction of polycyclic aromatic hydrocarbons in smoked cheese

Abstract

Background, Context or Rationale

Polycyclic aromatic hydrocarbons (PAHs) are hazardous compounds of conventional food smoking, and their consumption can cause serious health effects. Although the EU controls some PAHs, maximum limits have not been set for smoked cheese. The use of lactic acid bacteria (LAB) is proposed as a biological detoxification of PAHs in traditional bacterial fermentation.

Aim(s)

This study investigated the biocontrol efficacy of a consortium (strains of Lactobacillus acidophilus, Lactiplantibacillus plantarum, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) in reducing PAH levels in Caucasian Shepherd Cheese using naturally smoked and direct-spiking models.

Methods

Cheeses were produced under two conditions: semi-industrial traditional smoking (n = 6) and laboratory-scale direct PAH spiking (n = 3). PAH concentrations were monitored via Gas Chromatography–Mass Spectrometry (GC–MS) over a 90-day maturation period. Microbiological viability and physicochemical properties were assessed using General Linear Models to evaluate reduction kinetics.

Major Findings

LAB treatment decreased total PAH4 levels (from 14.76 to 8.59 μg/kg) in the samples naturally smoked. Reductions of 41.2% for spiked samples were achieved, with concentration effects being the only limiting factor. The major detoxification pathway was physical adsorption on the bacterial biomass due to pH-induced Zeta potential (surface charge) alterations. The consortium also remained viable under the smoking condition and showed potent antifungal activity.

Scientific or Industrial Implications

The results demonstrate that defined LAB starter cultures are an effective biocontrol method for reducing carcinogenic PAHs in smoked cheeses. This biological approach allows traditional dairy producers to ensure regulatory compliance and enhance consumer safety while maintaining product authenticity.