Lentilactobacillus parabuchneri—the main producer of histamine in cheese—survives the vat pasteurisation of milk

Background

Histamine is one of the most toxic dietary biogenic amines, and it can accumulate at high concentrations in certain types of cheese. Therefore, it is important to take measures to prevent its accumulation in this food. One of the main producers of histamine in cheese is Lentilactobacillus parabuchneri, which decarboxylates the histidine released during the proteolysis of milk casein. It is common for this bacterium to be present in milk and thus enter the cheese manufacturing process. Therefore, to avoid histamine accumulation, it is critical that L. parabuchneri be eliminated from raw milk.

Aim

The present work assesses the efficiency of vat pasteurisation to eliminate histamine-producing dairy L. parabuchneri strains.

Methods

Milk samples inoculated with dairy histamine-producing L. parabuchneri strains were subjected to vat pasteurisation (63°C for 30 min), and the viability of the strains was determined. Further, those L. parabuchneri strains found resistant to vat pasteurisation were assessed for their thermoresistance at higher temperatures (68°C, 73°C or 78°C) for 30 min.

Major Findings

The results obtained in this work showed that milk remained contaminated with heat-resistant, histamine-producing L. parabuchneri strains after vat pasteurisation (63°C for 30 min). However, increasing the temperature to 68°C drastically reduced the viability of these strains.

Industrial Implications

The slight increase of the vat pasteurisation temperature provides a simple way to drastically reduced the viability or even potentially eliminate histamine-producing L. parabuchneri from milk, which would prevent the accumulation of histamine in cheese.