Activité antifongique de la réutérine produite par Lactobacillus reuteri ATCC53608 dans les yogourts brassés

Authors: Pilote Fortin, Hélène
Advisor: Fliss, IsmaïlSt-Gelais, Daniel
Abstract: Food industry is now a worldwide economic sector. Market expansion and the increase of import and export have forced food industries to develop methods to increase shelf life of food products. Freezing, refrigeration, drying, concentration, modified atmosphere packaging and the used of preservatives are examples of technologies used in food industries. However, food is still prone to microbial contamination that can cause foodborne illness and food losses and waste. Food losses and waste represent a huge economic and environmental challenge for the global agri-food market. In 2010, FAO produced a global report reporting the main causes of food losses and the sector most affected by the crisis. In industrialized countries such as Canada, more than 40% of food losses occur during processing. In addition, in North America, dairies are the second most affected sector for losses after fruits and vegetables. One of the main causes of dairy contamination is the presence of yeasts and molds in products. This contamination causes waste directly at the plant, but it can also causes food recalls. For an industry, one recall can cost between $10 M US and $30 M US each time. In addition, the loss of consumer trust in products is significant in the balance of negative impacts. To limit the occurrence of microbiological contamination, processors used diversified control methods including the use of traditional preservatives such as salts and antifungal compounds as natamycin. But tendency showed that customers are more reluctant to buy products containing preservatives. They ask for natural products that are safe for health, reduced in salt and good for the environment. In addition, preservatives are very limited in dairy products, particularly in yogurt. The yogurts are more prone to mold and yeast contamination than other dairy products because of their composition and the presence of potential contaminants in flavoring ingredients and in production environments. The use of bioprotective lactic cultures and their antimicrobial metabolites in food preservation is a very promising natural solution in the context of reducing the use of traditional preservatives and maintaining the quality of food products. This study investigated the use of an antifungal bacterial metabolite, reuterin, in a stirred yogurt to meet the needs of dairy processors for an effective and natural antifungal solution. Results showed that reuterin have a great spectrum of action against both yeasts and molds. The used of reuterin in stirred yogurt was more efficient than natamycin for mold control when used as an antifungal ingredient. However, reuterin have reduced the population of lactic culture used in yogurt processing. Future studies have to be achieved to limit the action of reuterin on lactic culture starters to use it as an antifungal in yogurt. The used of reuterin as an antifungal is promising to reduce potential mold contamination in dairies.
Document Type: Mémoire de maîtrise
Issue Date: 2019
Open Access Date: 26 September 2019
Grantor: Université Laval
Collection:Thèses et mémoires

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