ORCID

0000-0002-3693-6375

Department

Biological Sciences

Full-time or Part-time Study

Full-time

Level

Postgraduate

Presentation Type

Poster

Supervisor

Michael Callanan

Abstract

An increase in vegan diet preference, lactose intolerance, calorie concern and environmental awareness has led to a rise in the popularity of plant-based alternatives to bovine milk. However, there are still gaps in understanding how known bacterial food contaminants behave in plant-based beverages. The present study is the first to compare the growth of food-pathogens Listeria monocytogenes and Salmonella enterica, food spoilage Bacillus subtilis and an industrial milk product isolate, spore-forming Paenibacillus in commercially available ultrahigh temperature processed bovine milk and plant-based milk alternatives (coconut, almond, cashew). Beverage samples were inoculated with a strain cocktail or individual strains of either Listeria, Salmonella, Bacillus or Paenibacillus, respectively (approximately 1 x 103 CFU/mL) and stored at chilled and ambient temperatures (4 °C, 8 °C or 20 °C). Bacterial strains used in the study were capable of proliferating in plant-based beverages at higher rates than in bovine milk at 8 °C and 20 °C for Listeria and 20 °C for Salmonella and Paenibacillus, respectively. Bacillus subtilis grew equally fast in bovine milk and plant-based milk at 20 °C. No statistically significant difference (p > 0.05) in growth rates between different types of tested beverages was observed at 4 °C and 8 °C for Listeria and Salmonella cocktails, respectively. These data suggest that plant-based beverages may present a significant risk for listeriosis and salmonellosis, and post-opening recommendations should be carefully considered.

Keywords:

Listeria, Salmonella, Paenibacillus, Bacillus, Plant-based beverage, Milk, listeriosis, salmonellosis

Start Date

2-11-2023 11:15 AM

End Date

2-11-2023 12:00 PM

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Nov 2nd, 11:15 AM Nov 2nd, 12:00 PM

Growth of food-borne pathogens Listeria and Salmonella and spore-forming Paenibacillus and Bacillus in commercial plant-based milk alternatives

An increase in vegan diet preference, lactose intolerance, calorie concern and environmental awareness has led to a rise in the popularity of plant-based alternatives to bovine milk. However, there are still gaps in understanding how known bacterial food contaminants behave in plant-based beverages. The present study is the first to compare the growth of food-pathogens Listeria monocytogenes and Salmonella enterica, food spoilage Bacillus subtilis and an industrial milk product isolate, spore-forming Paenibacillus in commercially available ultrahigh temperature processed bovine milk and plant-based milk alternatives (coconut, almond, cashew). Beverage samples were inoculated with a strain cocktail or individual strains of either Listeria, Salmonella, Bacillus or Paenibacillus, respectively (approximately 1 x 103 CFU/mL) and stored at chilled and ambient temperatures (4 °C, 8 °C or 20 °C). Bacterial strains used in the study were capable of proliferating in plant-based beverages at higher rates than in bovine milk at 8 °C and 20 °C for Listeria and 20 °C for Salmonella and Paenibacillus, respectively. Bacillus subtilis grew equally fast in bovine milk and plant-based milk at 20 °C. No statistically significant difference (p > 0.05) in growth rates between different types of tested beverages was observed at 4 °C and 8 °C for Listeria and Salmonella cocktails, respectively. These data suggest that plant-based beverages may present a significant risk for listeriosis and salmonellosis, and post-opening recommendations should be carefully considered.