| Shredded mozzarella cheese is popular and consumption is growing at a rate of 4% every year. By the year 2009, mozzarella cheese is expected to be the most popular variety of cheese in North America. Listeriosis, a food-borne disease caused by Listeria monocytogenes has been linked with the consumption of soft varieties of cheese. As markets change with consumers demanding more natural foods free from chemical preservatives, researchers are investigating the use of naturally occurring antimicrobials instead. The present work examined the effectiveness of rosemary and thyme oil as volatile antimicrobial agents in cheese against L. monocytogenes . The experiments involved inoculation of low and full fat cheese with a cocktail of different strains of L. monocytogenes at 3 log10 cfu/g. The inoculated cheese was treated with rosemary and thyme oil either separately or together and stored at 4 and 10°C for 20 or 15 days, respectively. Preliminary experiments showed that one of the five strains of L. monocytogenes used was resistant to rosemary and thyme oil. Therefore, further experiments were done with a cocktail of four strains. (Abstract shortened by UMI.)... |
