Autoinducer-2-like activity associated with foods and its interaction with food additives.
The autoinducer-2 (AI-2) molecule produced by bacteria as part of quorum sensing is considered to be a universal inducer signal in bacteria because it reportedly influences gene expression in a variety of both gram-negative and gram-positive bacteria. The objective of this study was to determine whether selected fresh produce and processed foods have AI-2-like activity and whether specific food additives can act as AI-2 mimics and result in AI-2-like activity. The luminescence-based response of the reporter strain Vibrio harveyi BB170 was used as the basis for determining AI-2 activity in the selected foods and food ingredients. Maximum AI-2 activity was seen on the frozen fish sample (203-fold, compared with the negative control) followed by tomato, cantaloupe, carrots, tofu, and milk samples. Interestingly, some samples were capable of inhibiting AI-2 activity. Turkey patties showed the highest inhibition (99.8% compared with the positive control) followed by chicken breast (97.5%), homemade cheeses (93.7%), beef steak (90.6%), and beef patties (84.4%). AI-2 activity was almost totally inhibited by sodium propionate, whereas sodium benzoate caused 93.3% inhibition, compared with 75% inhibition by sodium acetate. Sodium nitrate did not have any appreciable effect, even at 200 ppm. Understanding the relationships that exist between AI-2 activity on foods and the ecology of pathogens and food spoilage bacteria on foods could yield clues about factors controlling food spoilage and pathogen virulence.
Lu
Lingeng
L
Poultry Science Department and Institute of Food Science and Engineering, Food Safety and Environmental Microbiology Program, Texas A&M University, College Station, Texas 77843, USA.
Hume
Michael E
ME
Pillai
Suresh D
SD
D005503:Food Additives; D005516:Food Microbiology; D005519:Food Preservation; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000235:genetics* / Q000378:metabolism; D007783:Lactones / Q000378:metabolism; D015398:Signal Transduction; D014733:Vibrio / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
D005503:Food Additives; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine