Opportunities and Limitations of Natural Antimicrobials

Posted on:July 9, 2014

July 9, 2014, Global Food Forums — The following is an excerpt from the Ingredion sponsored “2013 Clean Label Conference Report.”

2013 Clean Label Conference-Kathleen Glass-Antimicrobial Alternatives

Click to view PDF of chart.

The primary function of food antimicrobials is food safety; the secondary function is shelflife extension. “In order to be effective as an antimicrobial,” explained Kathleen Glass, Ph.D., Associate Director of the Food Research Institute at University of Wisconsin Madison, “several factors need consideration.”

“Concentration of active compounds, antimicrobial solubility, dissociation constant, food composition (e.g., fat, moisture, hydrophobic proteins, free iron, pH, salt, water activity),synergistic effects between antimicrobials, processing, cooling, and storage temperature and times all affect antimicrobial effectiveness,” Glass continued.

A key characteristic of antimicrobials is amphiphilcity. An amphiphilic antimicrobial is partially lipophilic, with ability to pass through cell membranes; and it is also partially hydrophilic and, thus, is soluble in the aqueous phase. Sodium chloride is a conventional antimicrobial that reduces available water. Others include organic acids and their salts, such as lactate, acetate, diacetate and antimycotics (both acid and salt forms), like sorbate, benzoate and propionate. Nitrite, phosphates and some antioxidants are also included.

To be considered a “natural antimicrobial,” it is generally understood that the compound must be naturally occurring or directly extracted using simple methods, chemical reactions or naturally occurring biological process. No petrochemicals or genetic engineering can be used, explained Glass. No processing could be used that would not be done in a home kitchen. Antimicrobials from natural sources include microbial, plant or animal sourced compounds. Microbial sources include fermentation byproducts,
like organic acids and other primary metabolites, such as bacteriocins like nisin; competitive cultures, bacteriophages and natamycin (pimaricin); and minerals
and gases, like sodium chloride and 100% CO2 or CO. Plant sources include spices, extracts, essential oils, oleoresins, natural wood-smoke components, natural nitrate or nitrite and fatty acids. Animal sources include lysozyme, chitosan, lactoferrin and milk lactoperoxidase.

Fermentates are commercially available, proprietary ingredients that are derived from culturing sugar or milk and spray-dried. Often, they are blends of organic acids like lactic, propionic and acetic. These may or may not contain bacteriocin activity, and their byproducts depend on what starter cultures are used (for example, Propionibacterium,
Lactococcus, Pediococcus, etc.). The substrate and controls, such as temperature, oxygen and nutrient availability, also help determine the fermentation byproducts.

Organic acids in their undissociated form enter the cell, lowering its internal pH, denature proteins, disrupt proton motive force, inhibit membrane transport and starve cells.

Chelating metal ions can cause sub-lethal injury to pathogens and enhance efficacy of other antimicrobials. Organic acids and salts have optimized efficacy with
lower pH values (<5.5, near pKa) and lower temperatures (4 vs. 7 or 10°C)—except when the pH is <4.6; then, combined stress with higher temperatures increases inactivation rate. Combining with other antimicrobials also optimizes efficacy.

Bacteriocins are polypeptides that inhibit other closely related species. They are the byproducts of lactic acid bacteria fermentation, such as nisin, pediocin and reuterin.
Active against Gram-positive bacteria, they bind to receptors, which affects pore formation, causing leakage of molecules and cell death of pathogens. Bacteriocins
are bacteriocidal but have some disadvantages. Bacteriocins may be inactivated by proteolytic enzymes in raw foods, and some microbes have developed resistance.

Additionally, they are less effective in high-fat foods, and they also may inhibit beneficial competitive microflora. Bacteriocins work best in low-fat foods, with pH <6, and in combination with other antimicrobials.

Plant extracts, spices and glycerides used as antimicrobials are native compounds that protect the plant. They can be extracted with water or ethanol and concentrated. Common plant extracts used in foods that provide flavor and antimicrobial activity include
cinnamon, thyme, mustard, cloves and oregano. Antioxidants commonly used in foods that also provide antimicrobial activity include dried plum, rosemary, tocopherol, (vitamin E) and ascorbate (vitamin C).

Disadvantages of plant extracts include variability due to variety, extraction methods and agricultural practices. They can also partition into the fat phase, which tends to make them less effective and also may impart strong odor, flavor or color. There may be unknown toxicological effects at higher concentrations. Activity may also decrease after heating
some extracts.

Clean label antimicrobials can be applied to a wide variety of foods. Typically, they are ingredients familiar to consumers, yet they can enhance the safety of foods. Optimization
of ingredients can reduce usage levels, improve sensory attributes and be cost-effective.

CLC-Glass chart-online-pdf

Kathleen Glass, Ph.D., Associate Director, Food Research
Institute, University of Wisconsin-Madison.,

Natural Antioxidants: Maximizing Effectiveness for Shelflife Extension

Posted on:May 12, 2014

May 12, 2014, Global Food Forums — The following is an excerpt from the Ingredion sponsored “2013 Clean Label Conference Report.”

2013 Clean Label Conference-Shahidi-Chart

Click to view PDF of chart.

Antioxidants, when present in food or in the body at low levels, can delay, control or prevent oxidative processes leading to food quality deterioration or initiation and propagation of degenerative diseases. Antioxidants are generally phenolic and polyphenolic in nature and can be either synthetic or natural.

Effective at low concentrations, antioxidants are nontoxic; have good carry-through properties; and often are of reasonable cost, said Fereidoon Shahidi, University
Research Professor in the Department of Biochemistry at Memorial University of Newfoundland in St.John’s, Canada. Primary antioxidants act as free radical scavengers and reducing agents. Synthetic antioxidants in foods include BHA, BHT, TBHQ and PG. Ascorbic acid and tocopherol can either be synthetic or naturally sourced, while mixed tocopherols, rosemary, sage and green tea are natural. Secondary antioxidants include EDTA and citric acid, which deactivate pro-oxidants.

Consumers now demand clean labels with no artificial ingredients, while longer shelflives and stability in foods are also expected. “Food processors can meet the needs of both groups by using plant-derived natural extracts,” offered Shahidi.

Over 5,000 polyphenolics have been identified in different plants. These compounds are present to protect plants against herbivores; attack by microorganisms; and from stress due to sunlight. Antioxidants also participate in wound-healing in plants, and they attract pollinators.

Important components of functional foods, antioxidants occur as phenolic acids (hydroxybenzoic acid derivatives), phenylpropanoids (cinnamic acid derivatives), tocols (tocopherols and tocotrienols), flavonoids, isoflavones, coumarins, tannins, carotenoids, phospholipids, amino acids, protein hydrolysates, ascorbic acid (vitamin C) and many more.

Lipid oxidation, causing flavor, odor and shortened shelflives in food, happens with time, light, heat or enzymes. Metals, like iron and copper, which all foods have, are initiators. With iron, Fe2+ is more soluble than Fe3+ and is more than 100 times more reactive than ferric.

“Photooxidation requires singlet oxygen, produced by interaction of light and a sensitizer like chlorophyll. This reaction is unaffected by most antioxidants but is inhibited by quenchers of singlet oxygen, such as beta-carotene,” Shahidi stated.

Natural antioxidants are available commercially. Rosemary extract, green tea extract and mixed tocopherols are commonly used in clean label products. Rosemary has
FDA GRAS status (21CFR 182.10); it contains carnosic acid and carnosol, extending shelflife in meats, poultry, seafood, edible oils, snacks, sauces and dairy products. Green tea contains catechins and can be used in the same products as rosemary. Natural tocopherols are usually a mixture from deodorizer distillate. The most abundant
and commonly used is from soybean oil processing, containing mainly gamma, delta and alpha tocopherol.

Applications for rosemary and green tea extracts include meat, poultry and seafood, which are highly susceptible to oxidation, resulting in a warmed-over flavor, discoloration and protein degeneration. Baked products are susceptible to oxidation because of long shelflife requirements. Mayonnaise, dressings, soups and sauces have a large oil-water interface and complex food matrix that increases their susceptibility to lipid oxidation.

Oxidation risk also is high in margarines, which have a biphasic food matrix. Meanwhile, shortenings are more saturated, but one needs to be aware of their trans fatty acid content and governing regulations. Nutrient content claims can also be made for antioxidants,
if they have an established RDI according to 21CFR 101.54(g) and are present in amounts qualifying for the claims. Vitamins A, C and E, riboflavin and selenium are examples.

Antioxidants without RDIs do not qualify, and many warning letters have been issued by FDA for misuse of the term, advised Shahidi. Many plant extracts provide naturally derived antioxidants that offer both clean labels and health benefits in foods, he concluded.

For a link to the chart accompanying this seminar write-up, please click: Shahidi chart–pdf–2013 CLC.

Fereidoon Shahidi, Ph.D., Department of Biochemistry,Memorial University of Newfoundland, St. John’s, NL,Canada A1B 3X9


When Natural Isn’t Good for You: Managing Food Safety, Litigation & Regulatory Risk

Posted on:May 1, 2014

What is clean labeling? There is no uniform definition, but in part, clean labeling is a response to consumers’ lack of knowledge regarding food science and safety. “Clean labels” tend to involve: 1) reducing the number of ingredients generally; 2) eliminating “chemical sounding” ingredients; and 3) implying “natural” without necessarily using that term.

Xanthan Gum - Bob's Red Mill

Xanthan gum was used as an example of the subjective nature of the term “natural.”

Clearly, there is pressure on industry from consumers and advocacy groups for labels with pronounceable words. “The exception is if the ingredient is ‘hip’ and sounds natural; for example, ‘açai’ where the pronunciation gets a pass,” explained Anthony Pavel of Morgan, Lewis & Bockius LLP. Clean label is a subjective term influenced by consumers’ lack of knowledge or misunderstanding of ingredients, said Pavel. Take, for example, xanthan gum. Xanthan gum is the product of fermentation of sugars and, depending on the production technique, can be considered a “natural” ingredient. Nonetheless, there has been some level of reformulation to remove xanthan gum, because it sounds artificial. However, xanthan gum ironically assists in the formulation of gluten-free baked goods, another consumer trend based at least somewhat upon misunderstanding.

Consumers are also interested in good prices; however, many are willing to pay a premium for organic and “natural” products. Taste, texture, healthfulness, good shelflife—yet minimal processing and safety—are all desirable properties. Labels also must comply with FDA and FSIS requirements.

For example, ingredients are still required to be listed by the common and usual name, unless a regulation provides for a different term. Sugar is still sugar; highfructose corn syrup is not simply “corn syrup.” Exemptions to listing are limited in number and include incidental additives and processing aids that are present at insignificant levels with no function in the finished product. An insignificant level is not clearly defined, except with sulfites; they are considered to be incidental only if present at less than 10ppm.

Ingredients many consider to be “natural” and organic have some overlap, but not always. For example, the USDA’s National List of organic ingredients currently allows ammonium bicarbonate, calcium hydroxide, potassium carbonate, tetrasodium pyrophosphate and xanthan gum in certain organic products, even though they likely wouldn’t be considered “clean label” ingredients.

Pavel stressed that when reformulating to create a clean label product, safety should be the number one concern. Formulation changes that affect shelflife and stability need to be validated and reviewed in the context of final labeling. For preservatives, there are not always effective clean label alternatives.

“Labels must be truthful and accurate, not misleading or false in any way. Omission of material facts can be misleading. FDA places a big emphasis on front-ofpackage claims, and FTC has increased scrutiny of foods. Health-related claims are becoming more prevalent in food advertising, and so are being given increased scrutiny,” advised Pavel. Statements that claim to treat or prevent disease are a big target, he added.

Specific food additives are also under attack by consumer pressure groups. For example, CSPI has a Food Additives mobile app which warns consumers about ingredients. The app warns that caramel coloring may sound innocent, but may made with ammonia, sulfites or both. All issues discussed here are potential targets. FDA is picking its labeling battles as a result of strained resources.

At this point, natural claims are a lower priority than safety issues. A gap has been created by FDA’s inaction on developing a definition of “natural,” but lawyers in the plaintiffs’ bar are filling that gap and suing companies directly over their labeling and marketing claims.

In conclusion, there is a need to respond to consumer demand for clean labels, but reformulation requires a holistic review of safety, shelflife, product attributes and related label claims. Regulatory requirements must still be met, and consumers need to be educated.

This is an excerpt from the 2013 Clean Label Conference Report.

Cooking to Save Your Life – More than a Cookbook

Posted on:

cooking to save your life book cover(June 1, 2014—Global Food Forums, Inc.) In the opening page of  “Cooking to Save Your Life,” by Chef Kurt Stiles, John Morey, Executive Chef of DNC Sport Service, Bank of America Stadium, Carolina Panthers writes “Five short years later [after Chef Stiles’ stroke], Kurt has taken all his experiences, knowledge and love, and put it to work. I believe his research in this book comes from his life experience, passion, and knowledge of good cooking. I know using this cookbook will help families and friends eat healthier to live life fully!”

This is more than a cookbook. It is a story of the experiences endured by a successful father of a young family upon having a stroke and how he dealt with it. Most of the first section has been written by his friends and family and touches on topics ranging from his therapy and natural medicine to the challenges faced by caregivers. From there it segues into fitness and his new lifestyle, meal planning and lastly some 180 pages dedicated to healthful food recipes.

“Extras” include a system of allergen icons to indicate the presence or absence of allergenic ingredients in the basic recipes, ideas for substitution of certain ingredients to better customize for health concerns and personal interests, the nutritional content of recipes and personal notes.

I am posting a blog on this book, not only because Chef Stiles is a friend and his book is an unusual spirited effort that will benefit many, but also because of his creative usage of new tools now in the business world. They include use of the San Francisco-based crowd funding organization Indiegogo and a “must watch” short professional YouTube video on his story, see He raised $8,310 toward his modest goal of $7,500. He has a productive relationship with academia; three students at Southwest Minnesota State University’s (SMSU’s) Culinology & Professional Writing and Communication programs helped him with the book and he now donates $1 per book sold to SMSU’s Culinology Foundation for scholarships and another $1 is donated to help stroke survivors.

Finally, the recipes themselves are heartfelt suggestions from Chef Stiles that provide information for individual customization to one’s own needs and desires and, most importantly, made me want to run to the kitchen to try them out.

For more information, Chef Kurt Stiles can be reached at For more information on purchasing the book “Cooking to Save Your Life,” click on the link.

— Claudia Dziuk O’Donnell, Co-owner, Global Food Forums, Inc.

New Natural Sweetener D-psicose Marches toward Commercialization

Posted on:April 21, 2014
D-psicose natural sweetener

D-psicose is considered a “rare sugar” due to its scarcity in nature. Efforts are underway to extract it in a cost-efficient manner.
Illustration source: Wikipedia

(April 21, 2015—Global Food Forums) The preference for sweetness is innate in humans. Even newborns turn their heads toward a sweet solution versus one with plain water. Many animals also show a preference for foods with some sweetness. This preference is hard-wired; in nature, sweet foods correlate with those foods being a source of energy. See the Global Food Forums’ blog “Why is There So Much Sugar in our Foods?

With health concerns from obesity to diabetes, however, over-consumption of high-caloric sweeteners can be problematic. Consumer interests, and thus the food industry’s interest have turned to ingredients that provide sweetness with few to no calories. Additionally, some consumers segments strongly prefer “natural sweeteners” (regardless of their calorie or fructose content as in the case of agave syrup or honey).

Stevia and monk fruit extract are two high intensity (thus low calorie) sweeteners generally considered to be naturally-derived from plants. They have gained much popularity with the US food industry and their use is expanding globally.
However, a new, natural, almost zero-calorie sweetener may be not too far off. An article entitled “Formulating for a Sweet Perception with Natural Sweeteners” (Food Processing, April, 2014, page WF-15 and also online) examines D-psicose, a “rare sugar” found in nature and which has garnered FDA-notified GRAS status by at least one supplier.

Key physciochemical properties that may prove it very beneficial in future food formulations are that it is about 70% as sweet as sucrose but provides only 0.2kcal per gram (versus 4.0 for sucrose). In some applications it may also function as a bulking agent to help replace the volume needed in a formula when sucrose is reduced or removed.

—Claudia Dziuk O’Donnell, co-owner, editorial content, Global Food Forums, Inc.

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