Background:Microorganisms can grow over a wide range of salt or sugar concentrations. Only a few species can grow at the high osmotic pressures characteristic of environments having supersaturated brine and sugar concentrations (i.e., reduced water activity). Microorganisms that can grow in those high concentrations of organic solute, particularly sugars, are called osmophiles.
Yeasts are the most common osmophilic microorganisms encountered in environments of high osmolarity, such as foods containing high concentrations of sugar. Osmophilic yeasts are usually the cause of spoilage of high-sugar foods, such as jams, molasses, corn syrup, flavored syrups and toppings, honey, concentrated fruit juices, chocolate candy with soft centers, etc. Many of the common spoilage yeasts in the group belong to the genus Zygosaccharomyces. Osmophilic yeasts are of no public health significance but are of economic importance to the food industry.
This method allows for the enumeration of many common yeast and molds and is used as an indicator of food quality and spoilage (shelf-life) and the quality of hygienic conditions during food processing. It is often labelled as a general purpose method and is not specific to any species yeast and molds.
Method: Health Canada (MFHPB-22)
Turn Around time: 10 Business Days
Sample Required: 250g or swab
Reported Results: number of yeast and molds colonies per g (mL) of product.
SPECIMEN REQUIREMENTS
Container/Kit: Submit 250 grams of food in a sterile plastic sample bag with round wire closure.
Collection information: See Section Sampling under Food Sampling.
Requisition: Complete all fields of the form. See section Forms under Microbiology Sample Sheet.
Sterile bag: See section Form under Requisition for Containers and Supplies.
Preparation prior to transport: Keep refrigerated or frozen.
Shipping Instructions:
- Ship all foods in containers with hard walls and lids secured in the closed position.
- Shipping containers must be labelled with the submitting organization, unique identifier and contents e.g. FOOD SAMPLES on the outside of the container.
- Shipping containers used for food samples should be dedicated to food samples and not be used for other types of environmental samples.
- Ship dry foods and other shelf stable foods in a closed container at ambient temperature.
- Ship frozen foods in an insulated container with sufficient dry packs to maintain the frozen state.
- Ship perishable foods in an insulated container with sufficient cold packs to maintain a temperature as close to 4°C as possible. If ice is used, contain the ice in a manner that does not allow water contact with the samples.
- Submit all food samples to the laboratory as soon as possible
TEST INFORMATION
Yeast
& Molds should be absent from foods.