For this reason, peanut butter usually undergoes pasteurization
at temperatures of 70e75 C before packaging, although raw
peanuts have been subjected to a validated pasteurization process.
However, Li et al. (2009) reported thermal treatments of peanut
butter at 90 C for less than 30 min are insufficient to kill large
populations (5 log CFU/g) of Salmonella in highly contaminated
peanut butter. Shachar and Yaron (2006) found that thermal treatments
(usually less than 20 min) currently used to pasteurize
peanut butter are not sufficient for the destruction of salmonellae.
Several researchers have suggested that salmonellae have increased heat resistance in low-aw foods or in foods with high lipid content
(Juneja and Eblen, 2000, 2001; Mattick et al., 2000). Accordingly,
there is a need for the development of alternative technologies as
a secondary intervention to reduce pathogens, including Salmonella,
in peanut butter products by at least 4e5 log in the event that
hygienic conditions in the manufacturing facility are inadequate.