Genetic screening of biogenic amines production capacity from some lactic acid bacteria strains

There is an increasing interest for using lactic acid bacteria (LAB) as a starter and adjunct cultures for producing novel foods with particular functional traits. The ability of the starter to produce biogenic amines (BA) should be taken into account wherein protective starters should be selected to avoid hygienic and toxicological risks. This work aimed to study the possibilities of forming BA (histamine, putrescine, agmatine and tyramine) from thirty two LAB strains belonging to species of the genera Lactobacillus and Streptococcus that used in food products as well as strains isolated from healthy breast-fed infants. The analytical protocol involved using polymerase chain reaction (PCR) and thin layer chromatography (TLC) techniques to determine the ability of LAB strains to form BA. The presence of key genes involved in the biosynthetic pathways of the BA was also assessed by PCR. Six LAB strains gave positive results for putrescine production wherein the maximum level was 14.6 mg/kg. Six strains gave positive results for histamine production (maximum level was 31.7 mg/kg) and were positive for the presence of histidine decarboxylase (HDC) gene. Seven strains exhibited positive results for tyramines production (maximum level was 2.85 mg/kg) and were positive for the presence of tyrosine decarboxylase (TDC) gene. Eight strains gave positive results for agmatine production (maximum level was 174.5 mg/kg) and were positive for the presence of dihydrolase (deiminase) gene that responsible for agmatine formation. It could be concluded that the microorganisms used in food and dairy production should be screened carefully by PCR for their ability to produce BA.