Table Of ContentABSTRACT
MICROBIOLOGICAL QUALITY OF RETAIL “RAW” ALMONDS
IN THE UNITED STATES
Almonds are an important crop to California’s economy and make
up 83% of the world’s almond supply. Due to outbreaks of Salmonella in
retail almond products in the early 2000s, a new rule established under
the California almond marketing order was issued in 2007 requiring
almonds be pasteurized before they are packaged and sold to consumers.
These almonds are labeled “raw” or “natural” as it is thought that the
changes in nutritional and sensory characteristics are negligible. Since
the 2007 rule, no reported study has tested retail almonds for the
presence of Salmonella, nor has any reported study established a
microbiological profile of retail almonds. A total of 116 raw retail almond
samples were collected and tested for the presence of Salmonella spp.,
total mesophilic aerobic plate count, coliform count, and generic
Escherichia coli count. The presence of Salmonella was not detected in
any of the samples. The total aerobic mesophilic plate count was 5.14
log CFU/g, yeast count was 3.32 log CFU/g, mold count was 3.44 log
CFU/g, and coliform count was 2.83 log CFU/g. No generic E. coli was
detected. These results corroborate prior laboratory findings that the
required pasteurization of almonds is effective in protecting consumers
from foodborne illness. Pasteurization is a valid food safety intervention
method for nut processors, especially in the wake of several recent
recalls for Salmonella in other nuts (walnuts, macadamia nuts, pecans,
cashews, pistachios, hazelnuts, and pine nuts).
Brittany Blanco
August 2015
MICROBIOLOGICAL QUALITY OF RETAIL “RAW” ALMONDS
IN THE UNITED STATES
by
Brittany Blanco
A thesis
submitted in partial
fulfillment of the requirements for the degree of
Master of Science in Food and Nutritional Sciences
in the Jordan College of Agricultural Sciences and Technology
California State University, Fresno
August 2015
APPROVED
For the Department of Food Science and Nutrition:
We, the undersigned, certify that the thesis of the following
student meets the required standards of scholarship, format,
and style of the university and the student's graduate degree
program for the awarding of the master's degree.
Brittany Blanco
Thesis Author
Erin Dormedy (Chair) Food Science and Nutrition
Steven Pao Food Science and Nutrition
Dennis Ferris Food Science and Nutrition
For the University Graduate Committee:
Dean, Division of Graduate Studies
AUTHORIZATION FOR REPRODUCTION
OF MASTER’S THESIS
I grant permission for the reproduction of this thesis in
part or in its entirety without further authorization from
me, on the condition that the person or agency requesting
reproduction absorbs the cost and provides proper
acknowledgment of authorship.
X Permission to reproduce this thesis in part or in its
entirety must be obtained from me.
Signature of thesis author:
ACKNOWLEDGMENTS
I would like to thank Dr. Erin Dormedy for making it possible for
me to attend graduate school at Fresno State and introducing me to the
local IFT section. If it were not for her teaching, belief in me, and
support, I would not have fallen in love with the food industry as I have.
I would also like to thank my husband who has always believed in
me and supported me through everything. If it were not for his support
and willingness to do whatever it took to help me while I was going to
school I would not have been able to be as successful as I have. I would
not be the person I am today and would not have accomplished the
things I have without him.
TABLE OF CONTENTS
Page
LIST OF TABLES .................................................................................. vi
CHAPTER 1: INTRODUCTION ................................................................ 1
Research Statement......................................................................... 2
CHAPTER 2: LITERATURE REVIEW ....................................................... 3
Food Safety ..................................................................................... 3
Almonds .......................................................................................... 5
Microbiological Testing .................................................................. 11
CHAPTER 3: METHODOLOGY ............................................................. 14
Sampling Plan ............................................................................... 14
Microbiological Testing .................................................................. 14
Statistical Analysis ........................................................................ 19
CHAPTER 4: RESULTS AND DISCUSSION ........................................... 20
CHAPTER 5: CONCLUSION ................................................................. 24
REFERENCES ..................................................................................... 27
APPENDICES ....................................................................................... 33
APPENDIX A: DILUTION SCHEME ....................................................... 34
APPENDIX B: ALMOND SAMPLE CLASSIFICATION .............................. 36
LIST OF TABLES
Page
Table 1. Summary of studies conducted on the incidence of
Salmonella in almonds. ............................................................. 9
Table 2. E. coli, Coliform, Yeast, Mold, and APC Test Results (n=115) .. 21
1
CHAPTER 1: INTRODUCTION
Almonds are the top valued crop grown in California and have had
the largest export value for the past 3 years (California Department of
Food and Agriculture 2014). California almonds make up 83% of the
world’s supply, and 100% of the United States’ supply (Almond Board of
California 2015a). Raw retail almond products were recalled in 2001 and
2004 in Canada and the US due to the presence of Salmonella. After
these 2 outbreaks the Almond Board of California worked with the USDA
to put in place a pasteurization rule under the California almond
marketing order for almond products to prevent future recalls due to the
presence of Salmonella. Salmonella is the second leading cause of
foodborne illness with about 1.2 million cases every year (Scallan and
others 2011). The pasteurization rule requires a 4 log reduction of
Salmonella and multiple methods have been validated for use
(Agricultural Marketing Service 2007). To date only studies conducted in
the United Kingdom have tested retail almond products for the presence
of Salmonella (Little and others 2009, 2010). The only reported study
performed in the United States, after the pasteurization rule, tested for
the risk of Salmonella contamination in almond samples from processors
in California (Lambertini and others 2012). The detection and
enumeration of other microorganisms is also important to the food
industry. It is important to have an understanding of the microbial
profile of a food item as an indication of process control and sanitation.
A processor can target areas of improvement for quality as well as food
safety standards during processing. The total mesophilic aerobic plate
2 2
count of a food product provides an overview of the amount of
microorganisms in the product. Generic Escherichia coli and coliform
bacteria are important to test for as they are an indication of fecal
contamination. Yeast and mold are also of importance as they can cause
quality defects in food products and may produce metabolites that are
hazardous to human health. No reported study, after the pasteurization
mandate, has established the microbiological profile of retail almonds.
Research Statement
The purpose of this study is to provide data regarding the presence
of Salmonella in retail “raw” almonds and aid in the confirmation of the
effectiveness of the required pasteurization of almonds. This study will
also provide data establishing the general microbiological profile of retail
almonds.
Description:log CFU/g, yeast count was 3.32 log CFU/g, mold count was 3.44 log. CFU/g recalls for Salmonella in other nuts (walnuts, macadamia nuts, pecans,.
