484 JOURNAL OF COSMETIC SCIENCE
finished products days or weeks after product release testing indicated that the products
were within microbiology release specifications often is referred to as bacterial “rebound,”
or the Phoenix Phenomenon.1
A third goal of cosmetic microbiology has been to work with formulators to develop
preservative-free (e.g., self-preserving) products to meet consumer desires for products
that are more consumer friendly, environmentally friendly, and sustainable. Marketing
departments are asking cosmetic scientists and microbiologists to meet consumer demands
for safety and sustainability with products that do not contain preservatives, fragrances,
dyes, toxic chemicals, or packaging that are not biodegradable.
A more recent goal of cosmetic microbiology has been to conduct tests to better understand
the role of skin microflora (e.g., the skin microbiome), to include identification of beneficial
microorganisms, the interactions of these microorganisms with skin and mucous
membranes, and the effects of topical products on the skin microbiome. We are learning
from studies using probiotics and prebiotics to modulate the intestinal microflora, and it
is possible that selected microorganisms and ingredients will benefit desirable commensal
microorganisms in the skin microbiome.
The objective of this review is to discuss the evolution of cosmetic preservation. The
history of microbiology describes scientific advancements that provided the foundation for
the development of cosmetic microbiology. The changing use of preservatives involves a
transition from products with traditional preservatives to products that are preservative-
free. Studies of the skin microbiome are an active area of research in which we are learning
what microorganisms are on the skin and how they interact with each other and with the
skin to maintain homeostasis. It is anticipated that future studies will reveal the effect of
preservatives and products on the skin microbiome. Gaps in our knowledge need to be
identified and addressed in future products to ensure that products are sustainable because
they are adequately preserved, and that they have no adverse effects on the environment
or the skin/skin microbiome ecosystem. In this review, “cosmetic” refers to both color
cosmetics and toiletries.
HISTORY OF MICROBIOLOGY
Long before people knew about microorganisms, there must have been a belief that
something was happening when products spoiled by turning green or black and by
developing off-odors. People learned that some chemical agents were able to help preserve
water, foods, and other products. Hugo described the practice around 450 B.C. of keeping
water potable by storing it in copper or silver containers.2 Salts, oils, and natural balsams
were used for mummification. Over centuries, people learned that foods and other materials
could be preserved by means of salting, drying, fermenting, acidifying, and adding herbs,
honey, and natural spices. These methods of preservation were learned by experience and
were used even though people did not know about the existence of bacteria or other types
of microorganisms.
Microbiology today has evolved from the discoveries of physicians and scientists in Europe
and Asia up through the 19th century. These workers included Leeuwenhoek (used single-
lensed microscopes to observe microbes commonly known as “the Father of Microbiology”),
Pringle (used different salt solutions to prevent meat spoilage—considered to be a
forerunner of tests for the minimum inhibitory concentration of preservatives and other

485 Evolution and Challenges of Sustainability
antimicrobial compounds), Jenner (created the smallpox vaccine—the world’s first vaccine),
Koch (developed Koch’s postulates—the four criteria used to establish a causal relationship
between a microbe and a disease), Pasteur (introduced pasteurization and disproved the
doctrine of spontaneous generation—the idea that living organisms could arise from
nonliving materials), Lister (promoted sterilization during surgery using carbolic acid, or
phenol, as an antiseptic), Bierjinek (founded virology and environmental microbiology), and
Winogradsky (initiated and developed microbial ecology).3
The contributions by these scientists and others resulted in the rapid growth of microbiology
in the latter half of the 19th century, and the time between 1980–1900 has been referred to
as the Golden Age of Microbiology because it was a time when the role of microorganisms
in fermentation was becoming known, and the microorganisms that caused many diseases
were isolated and identified.3 The Society of American Bacteriologists was founded in 1899.
This organization was the forerunner of the American Society for Microbiology, which
currently has nearly 40,000 members.
The deplorable conditions of the meat-packing industry in Chicago at the beginning of the
20th century were brought to light in The Jungle by Upton Sinclair. This book raised a public
outcry that resulted in passage of The Pure Food &Drug Act of 1906. This Act helped
ensure the sanitary manufacture of foods and drugs, required drug ingredient labeling,
and prohibited the sale of adulterated (e.g., contaminated) and misbranded products in
interstate commerce. The Food and Drug Administration (FDA) was established in 1931
however, it was not given regulatory authority for the safety of foods and cosmetics or for
the safety and efficacy of drugs. Visible mold growth was the primary microbiological
problem of products reported around this time.4 However, it is likely that many products
were contaminated with significant numbers of bacteria that were not detected because
products may not have had preservatives, and microbiological testing probably was not
done on a regular basis.
The time from 1900–1930 was a time of consolidation in which many investigators worked
to better understand the wealth of information generated during the Golden Age of
Microbiology. In the early 1900s, The American Public Health Association published the
first edition of Standard Methods for Examination of Water and Wastewater and forerunners of
Standard Methods for Examination of Dairy Products were published. The Digestive Ferments
Company (DifcoTM) was established in 1914. DifcoTM introduced dehydrated culture media,
which provided considerable time savings for media preparation as well as uniformity of
culture media used for growing bacteria, yeasts, and molds. Research on preservatives
began, and parabens became the preservative of choice because of their antibacterial and
antifungal activity.4
In 1937, the “Elixir of Sulfonamide” incident resulted in more than 100 deaths in the
United States due to consumption of an antibiotic, sulfonamide, in diethylene glycol that
was not safety tested. This and other tragedies resulted in enactment of the Food, Drug,
and Cosmetic Act of 1938, which gave the FDA responsibility for requiring manufacturers
to ensure safety—including the microbiological safety—of their products.3
EVOLUTION OF COSMETIC MICROBIOLOGY
In 1941, Maison deNavarre published The Chemistry and Manufacture of Cosmetics to provide
scientific information about cosmetic raw materials, formulations, and product preservation.5