High pressure is an alternative to thermal processing and is used to preser
ve food. Listeria monocytogenes is a bacterium which grows at low temperatu
re, is able to multiply under vacuum, and is responsible for food poisoning
. Pressures of 100, 200, 300 and 400 MPa were used for 5, 10 and 15 min at
20 degrees C on pure culture, and on apple and plum jam baby food artificia
lly contaminated with Listeria. Pure culture was also to test pressures of
200, 300, 350 and 400 MPa at 5 degrees C for 30 min. The results were analy
sed statistically and showed that there were no significant differences bet
ween pressures of 100 and 200 MPa at 5, 10 and 15 min. However, at 300 MPa,
there were significant differences at 15 min. When the pressure treatment
was 400 MPa, significant differences were observed at pressure times of 5,
10 and 15 min. The results were fitted to a linear curve. In pure culture,
no viable cells were detected after high pressure treatment of 350 MPa for
30 min at 5 degrees C. The use of low temperature helps to maintain the sen
sory properties of the product.