High-pressure homogenization versus heat treatment: effect on survival, growth and metabolism of dairy Leuconostoc strains

GUGLIELMOTTI, D.; PATRIGNANI, F.; LANCIOTTI, R.; GUERZONI, M. E.; REINHEIMER, J.; QUIBERONI, A.

JOURNAL OF FOOD PROTECTION

INT ASSOC FOOD PROTECTION

Lugar: New York; Año: 2012 vol. 75 p. 1634 - 1641

0362-028X

The effect of high pressure homogenization (HPH) with respect to a traditional heat treatment on the inactivation, growth at 8ºC after treatments and volatile profile of adventitious Leuconostoc strains isolated from Cremoso Argentino spoiled cheeses and ingredients used for their manufacture was evaluated. Most of Leuconostoc strains revealed elevated resistance to HPH (8 passes, 100 MPa), especially when resuspended in skim milk. Heat treatment resulted more efficient in comparison to HPH to inactivate Leuconostoc cells at the three initial levels tested. Levels of alcohols and sulfur compounds increased during incubation at 8ºC in HPH-treated samples, while highest amounts of aldehydes and ketons characterized heated samples. Leuconostoc cells resuspended in skim milk and subjected to one-single pass HPH treatments using the industrial-scale machine showed remarkable falls on viable cell counts only when 300 and 400 MPa were applied. However, cell counts of treated sample rapidly rose after only 5 days of storage at 8ºC. Leuconostoc strains tested in this work were highly resistant to inactivation treatments applied. Nor high-pressure homogenization nor heat treatment assured their total destruction, even if they were more sensitive to the thermal treatment. To enhance the inhibitory effect on Leuconostoc cells, HPH should be combined with a mild heat treatment, which besides efficient microbial inactivation, could allow maximal retention of physicochemical properties of the product.