1. Toward food-poisoning proof meat with phage packaging
Devon Radford a, Brandon Guild b, Philip Strange a, Rafath Ahmed a, Sampathkumar Balamurugan a, Long-Tak Lim b
INTRODUCTION
MATERIALS & METHODS
RESULTS IN FOOD SYSTEM
Listeria monocytogenes and Salmonella sp. two of the top 3 causes of food-borne illness in Canada (Woolston et al. 2013)
14 CFIA recalls for L. monocytogenes since Jan 2016
4 CFIA recalls for Salmonella sp. since Jan 2016
L. monocytogenes grow under refrigeration and vacuum packaging conditions
Salmonella sp. survive refrigeration and vacuum packaging
Bacteriophage original, most common, successful and influential cause of bacterial death in biohistory (Hendrix 2002)
Phage documented with adaptions to overcome every known mechanism of bacterial resistance (Labrie et al. 2010)
Phage relatively stable at high and low temperature, salt, and water activity (Mora et al. 1962)
Phage can selectively kill specific pathogens while leaving beneficial bacteria unharmed (Brovko et al. 2012)
Most illness causing contamination occurs during processing after preliminary sterilization methods have lost effect
90% of food-product lifespan spent in close contact with packaging
Thus phage impregnated packaging a promising tool to control food-borne pathogens such as L. monocytogenes and Salmonella sp.
Aerobic
Anaerobic
PLA support film [30um thick]
Xanthan polymer containing pathogen specific phage (109 phage/cm2) [2um thick]
Pre-cooked sliced turkey or other food product
Samples of sliced turkey vacuum packed with phage coated PLA against Listeria monocytogenes
4oC
Coated packaging was evaluated on:
Inhibition of bacterial growth in culture under optimal growth conditions [rich media, 37oC, 20 h] (measured by OD600)
Control of L. monocytogenes growth or Salmonella sp. survival on surface inoculated, precooked sliced turkey stored at 4oC or 10oC, aerobically or anaerobically packaged
10oC
RESULTS IN CULTURE SYSTEM
Fig 3: Relative growth at 4oC or 10oC of diverse cocktail of L. monocytogenes on sliced turkey in aerobic or anaerobic Phage A511 coated packaging
DISCUSSION
L. monocytogenes cocktail growth significantly inhibited under A511 coatings on sliced turkey (P<0.05, Fig. 3) [over 14 days, at 4oC or 10oC, aerobically or anaerobically packaged]
Felix coatings caused smaller reductions in 6 strain Salmonella sp. cocktail survival vs. controls on sliced turkey at 10oC (P<0.05) but not at 4oC (P>0.05, figure not shown) [aerobic and anaerobic]
Listeria phages more effective than Salmonella phages for controlling contamination at low temperature
Phage embedded coatings proven effective for inhibiting pathogens in food systems(Fig 3)
OBJECTIVES
Develop packaging coated with thin layers of xanthan polymer embedded with phages targeting diverse strains of L. monocytogenes and Salmonella sp.
Characterize the anti-microbial effects of these phage coated packagings both in culture and in a food system
Evaluate effects of low temperature storage and aerobic vs anaerobic packaging conditions on phage dependent inhibition of L. monocytogenes and Salmonella sp. on meat
ACKNOWLEDGMENTS
Salmonella sp. and L. monocytogenes growth significantly inhibited on phage coated packagings in culture (P<0.01)
This work was supported by an NSERC VF-CGL postgraduate fellowship, and grants from NSERC and the Government of Canada.
Presenter: Dr. Devon Radford,
a Agriculture and Agri-Food Canada, Guelph Research and Development Center, 93 Stone Road West, Guelph, Ontario N1G 5C9
b University of Guelph, Department of Food Science, 50 Stone Road West, Guelph, Ontario N1G 2W1