Milk … it’s the only food readily converted to many varied foods, including butter, cheese, ice cream, yogurt, etc., through the use of minimal processing and the addition of a few simple ingredients. In the case of cheese and fermented dairy foods, such as kefir, sour cream and yogurt, the ingredients include cultures and enzymes.
There are three primary categories of cultures used in the production of cheese and fermented dairy foods. These are lactic acid bacteria (L.A.B.), which are often referred to as starter cultures, adjunct cultures and probiotic cultures.
Lactic acid bacteria ferment milk’s inherent lactose to lactic acid, providing desirable sour notes. By lowering the product’s pH, shelf life is also extended, as the acidic environment controls the growth of spoilage microorganisms.
Milk inherently contains L.A.B., and over time, sours naturally. However, in commercial manufacturing, end-product
specific bacterial strains are added as starter cultures. Because cultures are living microorganisms, suppliers are always trying to fine-tune the strains to improve efficiency. This enables a predictable fermentation time and yield, as well as a consistent finished product that meets flavor, texture and shelf life specifications. It is also necessary for suppliers to control for bacteriophage, which are viruses that infect bacteria and contribute to fermentation failure.
Chr. Hansen A/S, Denmark, addresses these considerations in its Fresco series of cultures for cottage cheese manufacturing.
“The two primary drivers for the Fresco program are an increase in product consistency and yield,” said Roy Riley, marketing director-cultures and enzymes for Chr. Hansen North America, Milwaukee. “The Fresco cultures improve the cheese’s consistency and dependability, which allows the manufacturer to process the cheese on time. This minimizes labor overrun costs due to slow vats and keeps the production schedule on time throughout the day. Moreover, the Fresco program has been proven to increase curd yield an average of 3.3% per vat, thus, increasing plant throughput using the same labor and equipment costs.”
Theis Bacher, vice-president of sales and commercial development-cultures and enzymes, added, “The opportunity to reduce production costs together with improved cheese quality and more robustness against phage attacks gives us reason to believe that we can increase the market potential for cultures in the cottage cheese market. Specifically, the phage robustness that comes with the new blending concepts behind the Fresco 3000 series provides greater dependability than ever before.”
This cottage cheese culture series provides for a smooth texture and mild taste, attributes the company believes will turn more consumers onto cottage cheese.
“The cottage cheese category has long been characterized by low growth and low innovation, but recent packaging and fruit flavor innovations have brought cottage cheese closer to the yogurt segment,” Mr. Bacher said. “We have been able to leverage our competences in yogurt culture technology. For example, we include texturizing water-binding strains that help retain moisture during the cook-out procedure.”
Getting into Greek yogurt
To make it easier for dairy processors to enter the burgeoning Greek yogurt category, DuPont Nutrition & Health, New Century, Kas., now offers YO-MIX Greek, a five-species yogurt culture blend that helps ensure consistency of culture delivery and eliminates plant mixing and measuring of starters. It is a one-step culture solution, thus, it reduces formulation errors during production.
“American consumers quickly embraced Greek-style yogurt because of its thick, creamy texture, high protein and nonfat content,” said Sonia Huppert, global product director, thermophilic cultures at DuPont Nutrition & Health. “For dairy manufacturers, the challenge has been not only to keep up with market demand, but to deliver a consistent product with every batch.”
The balanced blend is designed to deliver a mild dairy flavor over the shelf life of the yogurt.
“U.S. consumers prefer a mild-tasting yogurt with less tang,” said Jeff Lambeseder, cultures product manager at DuPont Nutrition & Health. “So we designed our culture blend to create a mild, less acidic flavor, and our sensory research demonstrates that it consistently delivers a mild taste throughout its shelf life.”
Because starter cultures influence the sensory profile of the fermented dairy food, selection is critical. It’s the difference between milk being fermented into buttermilk or sour cream.
Starter cultures also influence cheese variety. For example, not only do cheddar and mozzarella, the two most largely consumed types of cheese in America, differ in starter cultures, they also vary in manufacturing process. The former goes through a pressed curd process, while the latter is manufactured by cooking-and-stretching the curd, a technique referred to as pasta filata.
“A fast and consistent acidification process is essential to pasta filata plants,” said Ulf Mortensen, application manager-cheese-innovation with Chr. Hansen. “Traditional cultures for this segment are composed of only one or two thermophilic strains that drive most of the acidification process.
“Some of these cultures do a great job in an environment with low-phage pressure, but are vulnerable, because the impact of a phage attack on one of these strains will have a great impact on the acidification process, leaving no time to react on slow-downs or simply causing dead vats.”
The company’s new generation of cultures for pasta filata cheeses are composed of multiple strains that have each been carefully selected to provide fast and consistent acidification with the highest phage robustness and an attractive flavor profile.
“We have applied the newest culture design principles and compounding technology to further increase culture resistance against harmful bacteriophages and to reduce culture variation,” Mr. Mortensen said. “The series will support the cheese manufacturers’ effort to reduce downgrades and gain better process control, allowing our customers to optimize on milk solids and moisture content, or to steer towards target pH levels throughout the cheese making process.”
Anders Groen Noerager, global marketing manager of cheese cultures for Chr. Hansen, added, “When cultures are vulnerable to attacks from bacteriophages there is a risk of many downgrades or high scrap levels. This is a big loss for our customers considering the value of cheese, and there is also a considerable risk associated with the brand equity of large dairies today. The new cultures are specifically designed to deliver high productivity to pasta filata manufacturers, while minimizing the risks and costs associated with process variation and downgrades.”
Adjuncts for flavor and visual appeal
Adjunct cultures, also referred to as non-starter lactic acid bacteria (N.S.L.A.B.), are used in the manufacture of many cheeses to influence the flavor as well as visual appearance. They are purpose-made cultures added deliberately by the cheese-maker for a specific sensory effect. For example, adjuncts give blue cheese its pungent flavor, crumbly texture and characteristic blue veins.
Exopolysaccharide-producing N.S.L.A.B. create a ropy, often slimy solution, which may assist with increasing the viscosity of kefir or drinkable yogurt. They may also assist with improving the texture of low-fat cheese.
Adjunct cultures are responsible for eye development in certain cheeses. DuPont Nutrition & Health has created the Choozit Eyes range of propionic acid bacteria to help cheese makers achieve optimal eyes development easily and efficiently.
Specifically, new Choozit Eyes 2, which comes in a freeze-dried format for easy logistics, and in small packs to enable use in all size cheese manufacturing facilities, has been formulated to help semi-hard and hard cheese makers differentiate their product with intense and rich cheese flavor, along with fast eyes formation and a shortened ripening time.
Probiotics for health and wellness
The third category of dairy cultures — probiotics — is considered by some to be an adjunct; however, probiotics typically have little or no impact on taste or texture. Probiotics are live microorganisms, which when administered in adequate amounts confer a health benefit on the host.
Suppliers typically market individual probiotic strains that have been shown to exert specific health benefits in clinical trials. But because numerous meta-analyses conclude, with some cautions, that probiotic cultures, as a class, are beneficial to humans, some suppliers offer probiotic blends that provide a spectrum of functions, some of which involve capabilities unique to only one or a few strains but others that are more general to larger groups of microbes.
Probiotics are currently added to all types of dairy foods. Marketers tend to avoid making any claims to their benefits, as the term “probiotics” on package labels appears to be a strong enough marketing tool. According to the 2012 Food & Health Survey: Consumer Attitudes toward Food Safety, Nutrition & Health, commissioned by the International Food Information Council Foundation, Washington, 20% of consumers surveyed consider the inclusion of probiotics when making decisions about buying packaged food or beverages and 14% are trying to get a certain amount or as much as possible in their diet.
Enzymes reduce carbon footprint
Starter cultures typically produce enzymes, which are biological catalysts that speed chemical reactions in a natural way, thus improving fermentation efficiencies. In cheese making, enzymes are responsible for coagulation, the conversion of milk to curd. They are inert materials made of proteins and remain unchanged until deactivated by either heat or a drop in pH.
Scientists at Novozymes A/S, Denmark, have produced the first review of existing studies into the use of enzymatic solutions in various industries, confirming that enzymes provide significant savings on water, energy and raw materials, as compared to conventional processes. The review shows that small amounts of enzymes may be used in industrial processes, such as cheese making, to speed reactions and reduce the temperature at which processes take place, thereby reducing a company’s carbon footprint. This review was published in the March 2013 issue of Journal of Cleaner
The food sector contributes more than 20% of global greenhouse gas emissions, according to the Food and Agriculture Organization of the United Nations. Cheese ranks among the top-10 foods in terms of value chain carbon footprint. This is mostly due to milk intake, which has a footprint of 1.1 tons of carbon dioxide per ton of milk.
Recently, Chr. Hansen showed that cheese producers may reduce carbon dioxide emissions when using the Chy-Max M coagulant. The reduced carbon footprint is a production benefit that comes directly from the fact that using Chy-Max M means increased cheese yield. Exactly how big a yield increase and carbon dioxide reduction depends on the type of cheese.
To be specific, switching from a first-generation fermentation-produced chymosin to Chy-Max M will give a 22 kg to 54 kg of carbon dioxide-per-ton-of-cheese reduction of the carbon footprint due to the proven yield increase. The shift from a microbial coagulant will save 39 kg to 146 kg, while moving from animal rennet will save 38 kg to 70 kg.
For instance, an average producer of mozzarella cheese making 20,000 tons of cheese per year who switches to Chy-Max M could save 1,200 tons to 1,500 tons of carbon dioxide each year (depending on the type of coagulant the producer uses today).
“More and more customers are working with determination to reduce the carbon footprint of their production process,” said Rolando Saltini, coagulants marketing manager at Chr. Hansen. “We have a carbon dioxide calculator available for dairy customers who wish to get an overview of carbon dioxide emissions associated with producing cheese with the different types of coagulants.”
Henriette Oellgaard, senior manager in Chr. Hansen’s Corporate Social Responsibility department, added, “Assisting our customers in reaching their sustainability targets merely by choosing more sophisticated ingredients in their food production makes really good sense for us.”
Numerous ingredient and technology solutions are available to create business value while improving sustainability. The right cultures and enzymes may assist.