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Effects of Maillard Reaction Products on hilA Expression in Salmonella Typhimurium
Author(s) -
Kundinger M.M.,
ZabalaDíaz I.B.,
Chalova V.I.,
Ricke S.C.
Publication year - 2007
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2007.00600.x
Subject(s) - salmonella , virulence , biology , lysine , histidine , microbiology and biotechnology , arginine , enterobacteriaceae , pathogenicity island , maillard reaction , bacteria , food science , biochemistry , escherichia coli , gene , enzyme , amino acid , genetics
ABSTRACT: Salmonella is a foodborne pathogen causing severe gastroenteritis. Three types of Maillard reaction products (MRP) generated by heat sterilization of D‐glucose and L‐lysine, L‐histidine, and L‐arginine were studied at 2 different levels of supplementation (0.5% and 1.0%) for their influence on growth and virulence of Salmonella . Two methods, namely, real‐time polymerase chain reaction (RT‐PCR) and a β‐galactosidase gene fusion assay, were used to determine the expression of hilA , a regulatory gene for Salmonella pathogenicity. Neither the type of MRP nor their quantities up to 1.0% affected the growth rates of S. Typhimurium EE658 ( P > 0.05). When determined by β‐galactosidase assay, lysine MRP in both levels of supplementation were not found to have any effect on the hilA expression compared to the control. The addition of histidine and arginine MRP to M9 media (0.5%) increased by 2‐fold hilA induction and up to 6‐fold at the higher level (1%) supplementation of these compounds. Although somewhat inconsistent, RT‐PCR analyses of hilA expression confirmed the greater induction effect of arginine MRP on hilA compared to lysine MRP. In contrast to β‐galactosidase assay results, however, lysine MRP were found to increase hilA expression compared to the control in both supplementation levels in all trials. The potential of MRP serving as a bacterial virulence modulator may be a factor to be considered in food thermal processing when assessing Salmonella risk for causing foodborne disease.