The sales market and the production of foods containing probiotics has increased over the years. Americans’ spent nearly three times more on probiotic foods or products from 1994 to 2003 (NCCAM Oct. 2009).

How yogurt is made

  • Lactose is able to be broken down into glucose and galactose through the enzymatic activity of beta-galactosidase (Ustok et al. 2010). Lactic acid bacteria is a large catetory of different enzymatic products. Included in the category of lactic acid bacteria are the highest beta-galactosidase producers; Lactobacillus bulgaricus and Streptococcus thermophilus (Ustok et al. 2010). These two elements are commonly included in yogurt to ensure that the lactose is able to be broken down. According to NCCAM (2009), most of the bacterial cultures in yogurt or other products most often come from either the Lactobacillus or the Bifidobacterium strain.
  • In some studies including the work done by Da Cruz et al. (2009), the texture and taste of the yogurts were determined by which components they contained. A greater hardness value accompanied probiotic yogurts. Fermented milks have the ability to produce exopolysaccharides, contributing to an improved yogurt texture. The addition of stabilizers added into yogurt is not allowed in some countries, which leaves exopolysaccharide producing bacteria as the alternative (Da Cruz et al. 2009).
  • In order to increase shelf-life, some yogurts are heat-treated, which ends up killing some of the bacteria. In order to keep the helpful bacteria alive, it is important to keep yogurt refrigerated (Newman 2009). As well as heat-treatment, thickeners and stabilizers such as gelatin are added to increase shelf life (Newman 2009). In order to increase calcium absorption, milk powders could be used for enrichment (Angel de la Fuente et al. 2003). As well, the magnesium bioavailability is enhanced with the addition of dairy additives (Angel de la Fuente et al. 2003). Milk powder can also increase shelf life and work to thicken yogurt. Milk powder is rarely chosen to be added because of increased cost.
  • Abe et al. (2009), examined the production conditions which influenced the survival of bifidobacterium longum. Lower fermentation temperature as well as the additon of lactococcus lactis to the starter were two factors which significantly improved the survival of the bifidobacterium longus over 35 days (Abe et al. 2009). During the acidification process, yogurts can experience a drop in pH of about 3. When this change occurs, the amount of calcium and phosphorus associated with micellular proteins decreases (Angel de la Fuente et al. 2003).
  • For a dairy product to be called yogurt, it must have two specific types of bacteria: Streptococcus thermophilus (ST) and Lactobacillus bulgaricus (LB). ST produces acid and carbon dioxide, which both work to stimulate the growth of LB. In addition, the proteolytic activity of LB produces certain peptides and amino acids which are used by ST (http://www.foodsci.uoguelph.ca/dairyedu/yogurt.html). This yogurt is made with milk, sugars, stabilizers and various fruits and flavours along with the bacterial culture. Yogurt is made in four different steps: modifying the composition of the milk, pasteurization and homogenization, fermentation, adding other ingredients.
  • A) Modifying the composition of the milk: When the milk first arrives, the fat content is reduced by using a clarifier and a separator. This acts like a centrifuge that separates the fat from milk. The milk is then tested for its fat and solids content where the solids content increases. This increase in solids content improves the nutritional value of the yogurt and also makes it firmer.
  • B) Pasteurization and Homogenization: After the composition of the milk has been adjusted, stabilizers are added. Stabilizers include gelatins, gums, pectins and starch. They are used in the yogurt to increase its firmness by denaturing the whey protein, they also destroy any microorganisms that are present in the milk that could interfere with fermentation, they do not cause a big change in the flavour of the milk and lastly they cause the release of certain compounds in milk which work to stimulate a starter culture. After this, pasteurization takes place in either a continuous or batch process. The milk is then heated at a high temperature for a particular amount of time. The high temperature denatures the whey proteins which prevent the water from separation during storage. During the pasteurization, the milk is also homogenized. When this occurs, the fat in the milk is broken up into smaller particles. This creates a smoother product.
  • C) Fermentation: during this process, the milk is cooled to approximately 42°C, which acts as an optimal temperature for the growth of the starter culture. The milk is held at this temperature until a pH of 4.5 is reached. An important outcome of this process is lactic acid. It is the level of lactic acid that is used to determine if the yogurt is ready. A sample is titrated with sodium hydroxide and a value of 0.9% acidity and a minimum pH of 4.4 are the minimum standards in the United States.

Why do we eat yogurt?

The Consumer

  • There are three dimensions related to a proper understanding of what consumers look for in a product. Product-related factors including; physical and chemical properties, sensory quality (aroma, taste, texture) and product packaging make up the first group of factors. The second group focuses on consumer-related factors; age, gender, education and psychological factors. The third division for understanding consumer choices is related to the environment. This environmental category includes economic, cultural and social factors (Pohjanheimo & Sandell 2009).
  • Ares et al. (2010) performed a study to try and determine the most important factors which influence consumer purchase of yogurt. Brand and price were found to be the two most important non-sensory factors which impact consumer perception of functional foods (Ares et al. 2010). The brand of the functional food product is very important to consumers. Consumers link the brand with a promise and a guarantee from a particular manufacturer which the consumer links to quality.
  • If the consumers were found to have a higher interest in health issues, health claims of the food products also enters into the top factors for yogurt choice, including brand and price (Ares et al. 2010). Activia incorporates all three of these factors for consumer choice and purchase. Activia is from the Danone company, which is very well known. There are many health claims related to Activia yogurt, which grab the attention of consumer's who are health conscious. The increased price of Activia yogurt compared to other products is a result of both reputation and health claims. An increased price can be associated with a better quality product. These points demonstrate that the aspects of a consumer's food choice need to be throughly examined and incorporated into the product design and production (Pohjanheimo & Sandell 2009).
  • The overall liking of yogurt increased as the sugar content increased. Activia has a large amount of sugar per serving compared to some other brands of yogurt. However, due to the fact that many companies now want to focus on optimal health, new ideas to improve the taste and liking of the yogurt will need to be determined.

Restore the Good Bacteria

  • There are a number of factors which disrupt the natural microflora bacterial population in the human intestinal tract including; antibiotics and disease-causing bacteria (NCCAM Oct. 2009). Although antibiotics are used to remove harmful bacteria from the body, they are able to remove beneficial bacteria as well. This removal of numerous types and amounts of bacteria will lead to an unbalanced population of bacterial microflora (NCCAM Oct. 2009).

Relieve Symptoms

  • Scientific investigations have been proceeding further to identify specific symptoms which are most influenced by probiotics. The most evidence lies with the treatment of diarrhea. There is also some evidence to support that yogurt and probiotics may have a role in the prevention and treatment of urinary and female genital tract infections, treatment of irritable bowel syndrome and the reduction or reoccurrence of bladder cancer. Protiotics have also been shown to prevent and manage atopic dermatitis (eczema) in children (NCCAM Oct. 2009).
  • Yogurt has become widely recognized as a fermented milk product with various health benefits. It is a nutrient-dense food containing various vitamins and minerals, which can all aid one’s health.

Maintain or get the Beneficial Bacteria

  • Evidence suggests that the microbial flora that is present in the gastrointestinal tract of warm-blooded animals provides resistance to various diseases. Through one’s diet and environmental influences, this protective flora can be disrupted and this can lead to a reduction in its efficiency. By ingesting probiotics, one can attempt to re-establish the natural condition of the gastrointestinal tract and thereby decrease one’s susceptibility to disease (http://www.ncbi.nlm.nih.gov/pubmed/2666378). Various other factors can lead to the disruption of the natural microflora population within the human gastrointestinal tract. Antibiotics, which are used to eliminate harmful disease-causing bacteria, have also been found to remove the beneficial bacterium leading to an unbalanced bacterial population, which causes individuals to become more susceptible to disease (NCCAM). In order to be beneficial, these probiotics must be ingested daily. This is because only small amounts of bacteria can withstand the acidity in the body and also because bacteria will pass through the digestive system in a day or two and so they must be replenished (monography). The dominant population found in the intestinal tract of an adult human being contains anaerobic bacteria: Bacteroides, Bifidobacterium, Eubacterium, and Peptostreptoccocus while the sub-dominant population is made up of bacteria which belong to the Streptococcus and Lactobacillus families and also Enterococcus, Clostridium and yeasts. The presence of intestinal flora is able to facilitate carbohydrate, protein, lipid, vitamin and mineral metabolism (http://www.activia.ca/en/documents/Monographie_En.pdf). Most of the probiotics present in yogurts are similar to those found in the human gut and majority of the bacteria come from Lactobacillus or Bifidobacterium. This type of beneficial bacteria helps to protect against various other microorganisms that can cause disease.


  • Calcium has been widely recognized for its various potential health benefits. It is required for various tasks such as muscle contraction, secretion of enzymes and hormones, transmitting impulses throughout the nervous system as well as blood vessel expansion. This makes up <1% of the total body calcium and the other 99% of calcium found in the body is used for supporting the structure of bones and teeth (http://dietary-supplements.info.nih.gov/factsheets/calcium.asp).
  • Known for its preventative roles in osteoporosis, calcium is required from the diet in order to maintain proper concentrations within the body. If this does not occur, the calcium in the bloodstream will decrease. To balance this, the body moves calcium from the bones into the bloodstream which causes brittle bones and eventually leads to osteoporosis. For individuals that are lactose intolerant, yogurts are a beneficial source of calcium. This is because yogurt contains lactase which is the enzyme that is responsible for breaking down lactose (http://www.canadianliving.com/health/nutrition/the_health_benefits_of_yogurt_3.php). With the presence of lactase, lactose is hydrolyzed into its monosaccharides, glucose and galactose (http://dietary-supplements.info.nih.gov/factsheets/calcium.asp). In addition to calcium, vitamin D is present in most yogurts in order to aid in the absorption of calcium (http://www.nof.org/prevention/vitaminD.htm).
  • Calcium has also been associated with a decrease in blood pressure and a decreased risk of hypertension. The Dietary Approaches to Stop Hypertension (DASH) study tested the effects of three various eating patterns on blood pressure: a control which was a “typical” American diet; a diet high in fruits and vegetables; and lastly a diet high in fruits, vegetables and low-fat dairy products. The study found that the group which ingested the low-fat dairy products had the greatest decrease in blood pressure although they were not able to attribute this effect to calcium (http://dietary-supplements.info.nih.gov/factsheets/calcium.asp).
  • In addition to the roles of calcium above, calcium has been studied to determine its role in potentially preventing colorectal cancer. When given supplements of calcium carbonate, subjects had a reduced risk of adenoma in the colon which is a precursor to cancer. In two other trials, men and women who consumed 700-800 mg per day of calcium experienced a 40% - 50% lower risk of developing left-side colon cancer. Other studies conducted have found no significant differences in the risk of colorectal cancer when compared to a placebo. Due to the long latency period for developing colon cancer, studies should be conducted on a long-term basis to further understand the effect of calcium intake.

Vitamin A

  • Vitamin A, an antioxidant, is also found in Activia yogurts. It makes up 2% of one’s recommended daily intake (RDI). When the body breaks down food or when exposed to various environmental cues, free radicals can be produced and vitamin A works to protect the cells against the effects of these free radicals. In addition to its function as an antioxidant, it can play a role in the immune system, cell function, vision, bone growth and reproduction. (http://www.nlm.nih.gov/medlineplus/vitamina.html).

Vitamin B2 (riboflavin) and B12

  • Riboflavin (10% of RDI) is important for carbohydrate and amino acid metabolism. In addition, it aids in keeping the mucous membrane healthy (http://www.merck.com/mmhe/print/sec12/ch154/ch154d.html). Vitamin B12 is essential for red blood cell formation, DNA synthesis and neurological function. Vitamin B12 (15% of RDI) also functions as a cofactor for L-methylmalonyl-CoA mutase and methionine synthase. Methionine synthase acts as a catalyst for the conversion from homocysteine to methionine where methionine is required in order to produce S-adenosylmethionine. S-adenosylmethionine functions as a universal methyl donor for approximately 100 various substrates which include proteins, lipids, DNA, RNA, and hormones (http://ods.od.nih.gov/factsheets/vitaminb12.asp).


  • The mineral magnesium (4% of RDI) is needed for moer than 300 biochemical reactions that take place in the body. In addition it maintains normal function of muscles and nerves, steadies heart rhythm, strengthens bones and also supports a healthy immune system. It can also regulate blood sugar as well as maintain blood pressure, and plays a role in energy metabolism and protein synthesis (http://ods.od.nih.gov/factsheets/magnesium.asp).

Brief History

  • In the early 1930’s and beginning as a cottage cheese industry, Jude Delisle began selling fresh dairy products. Born in Quebec and during a trip to France, he discovered yogurt. He set up his business in Montreal where he first began selling to doctors who prescribed yogurt to patients as a medication. In 1963, businessman Leslie Jonas acquired Delisle and by 1967 it had become one of the leading producers of yogurt in Canada. By 1997, Delisle became Danone Canada. Now, with various brands such as Activia, Danone has become the top yogurt producer within Canada. (http://www.danone.ca/en/products/activia.aspx
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