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.
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.
Lingeng
L
Lu
Michael E
ME
Hume
Suresh D
SD
Pillai
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