A Natural Solution for California's Herds: African Catfish Peptides
California's cattle producers and agricultural communities are all too familiar with the rising challenge of antibiotic resistance, making common bacterial infections harder to treat in livestock. But imagine a future where we could tackle these infections with a natural, powerful alternative. Our research points to just that: antimicrobial peptides (AMPs) found in African catfish.
We're really excited about these peptides because African catfish thrive in pathogen-rich freshwater, naturally producing these robust immune compounds in their skin mucus as a defense. This natural origin makes them highly appealing alternatives to synthetic drugs.
Predicted Safety and Potent Action
One of the most compelling aspects of these AMPs is their predicted safety for mammals. Our initial computer analyses suggest that various catfish AMPs are generally recognized as safe (GRAS). We predict they'll be absorbed in the human intestine without causing liver, brain, or heart toxicity. Furthermore, lab tests on a promising peptide, NACAP-II, confirmed it was non-hemolytic, meaning it didn't damage rabbit red blood cells—a strong indicator of its potential safety for mammalian cells.
Beyond safety, these peptides demonstrate effectiveness against problematic bacteria. One study revealed NACAP-II's strong activity against Extended-Spectrum Beta-Lactamase (ESBL)-producing Escherichia coli—a critical concern for both animal and human health due to its resistance to many common antibiotics. Another peptide, ACAP-IV, also showed antibacterial activity against E. coli and Staphylococcus aureus. We believe these AMPs work by directly disrupting bacterial cell membranes, a mechanism that makes it harder for bacteria to develop resistance compared to how they resist traditional antibiotics.
The Path Forward
While these findings are very promising, we want to emphasize that this research is still in its early, laboratory stages. A key challenge we've identified is that some of these peptides have a high molecular weight, which might hinder their absorption if given orally. This means our future work will need to explore advanced delivery methods, potentially involving nanotechnology, or modify the peptides for better absorption and accumulation where they're needed most. Ultimately, more studies are essential to confirm their effectiveness and safety in living animals, such as cattle, and to develop strategies for large-scale production.
From Our Lab to Your Farm: Smarter Strategies for Antimicrobial Resistance
As fellow researchers who have been studying antimicrobial resistance (AMR) in California dairy cattle, we want to share some important insights from our recent work. Our studies highlight that while we don't focus on new types of drugs to replace antibiotics, the most critical "alternative" is actually smarter, more targeted management and a deep understanding of pathogen behavior on your farm. This approach aims to reduce the need for antibiotics or minimize the development and spread of resistance when antibiotics are necessary.
Identification, Synthesis, and In Vitro Activities of Antimicrobial Peptide from African Catfish against the Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli
Tackling Resistant Salmonella in Cull Cows
First, we've found that Salmonella in cull dairy cows, which contribute to the ground beef supply, often carries resistance to important antimicrobials like tetracyclines, ampicillin, and even ceftriaxone—a drug critical for human medicine. This is definitely a concern for public health. Our research shows that certain cow-level factors, such as prior antimicrobial treatment or culling due to lameness, are associated with higher odds of isolating resistant Salmonella. Conversely, culling a cow due to low milk production was associated with lower odds of resistance.
At the herd level, factors like the number of milking cows and monthly culling rates can also influence the presence of resistant Salmonella. This suggests that improving timely culling decisions—removing cows with mild disease problems before they escalate and require extensive antimicrobial therapy—could be an economical way to reduce the selection pressure for AMR. We also need to investigate specific reasons for culling, especially lameness, to understand its link to resistance.
Unpacking Mastitis: The Importance of Specificity
Second, regarding mastitis, we've extensively characterized Coagulase-negative Staphylococcus (CNS) species, which are the most common cause of intra-mammary infections (IMI). Historically, these have often been grouped into one class for convenience, or sometimes left untreated. However, our findings reveal a diverse range of different CNS species circulating on US dairies, with Staphylococcus chromogenes and Staphylococcus haemolyticus being the most prevalent. We've seen evidence of persistent subclinical infections, especially with S. chromogenes and S. simulans, where identical strains were isolated from the same udder quarter over consecutive sampling stages.
Our message here is that a better understanding of these specific CNS species and their genetic diversity is crucial for improved management and treatment outcomes. Instead of blanket approaches, identifying the predominant species on your farm can guide species-specific control strategies, including targeted treatment decisions to eliminate persistent infections and improvements in milking practices like teat dipping. This precise identification, perhaps through rapid and low-cost diagnostic tests, is a key step to managing mastitis effectively while minimizing broad-spectrum antibiotic use. The low number of clinical mastitis cases from CNS suggests they mainly cause subclinical chronic infections, reinforcing the need for targeted strategies.
Calves and Antibiotic Use: A Clear Connection
Finally, our work with pre-weaned dairy calves shows a direct link between antibiotic use and the rise of resistance. We observed that administering ceftiofur as a systemic injection or feeding neomycin-supplemented milk replacer to calves leads to an increased concentration of resistant Enterobacteriaceae in their feces. The peak of ceftiofur resistance occurred around three to four days after treatment, with levels decreasing to below pre-treatment levels by seven to eight days post-treatment. Similarly, neomycin resistance increased during administration and then decreased once the antibiotic was discontinued.
This clearly illustrates that AMR is acquired during treatment and can be lost when antimicrobial pressure is removed. This finding strongly supports the importance of prudent antimicrobial stewardship. While antibiotics are sometimes necessary, minimizing their use, especially extra-label use or prophylactic feeding where not strictly justified, can help preserve their effectiveness for when they are truly needed. Initial resistance observed in calves might also be linked to residual antibiotics in colostrum or environmental bacteria ingested by the calves.
The Real "Alternatives" are Smart Choices
In summary, the "alternatives" we emphasize aren't necessarily new medications, but rather strategic management decisions. This includes timely culling, species-specific diagnostics for mastitis, and responsible, prudent use of antibiotics in calves, all aimed at reducing the overall selection pressure for antimicrobial resistance on your dairy.
What specific management practices are you currently implementing to address antibiotic resistance on your farm?
Based on
- Molecular epidemiology of coagulase-negative Staphylococcus species isolated at different lactation stages from dairy cattle in the United States
- Association between herd management practices and antimicrobial resistance in Salmonella spp. from cull dairy cattle in Central California
- Estimating the Rates of Acquisition and loss of Resistance of Enterobacteriaceae to Antimicrobial Drugs in Pre-Weaned Dairy Calves
Our Research: Guiding California Dairies in the Fight Against Antimicrobial Resistance
As California dairy owners and farmers, our research provides crucial insights into managing antimicrobial resistance (AMR) on our operations. We want to emphasize the importance of judicious antibiotic use and strong stewardship practices to maintain herd health and preserve the effectiveness of these vital medicines.
Understanding Resistance Patterns in Your Herd
Our findings reveal important patterns of antimicrobial resistance in common bacteria (Escherichia coli and Enterococcus/Streptococcus spp.) found in the fecal samples of adult dairy cows across California. We observed very low resistance to several drugs commonly given to adult dairy cows, such as cephalosporins and penicillins. This tells us that these particular drugs remain effective when used appropriately.
However, we detected higher rates of AMR to drugs that aren't approved for use in lactating dairy cattle over months of age, including florfenicol, tildipirosin, tilmicosin, and tiamulin. The high resistance to florfenicol, for instance—a drug typically used in beef cattle or non-lactating dairy cattle and calves—might be linked to co-selection with other resistance genes or how resistance spreads between bacteria. These results truly underscore the importance of sticking to labeled drug uses and understanding how resistance can develop even to drugs not directly used in adult lactating cows.
Regional Differences and Management Impacts
We also identified significant differences in AMR across California's dairy regions and seasons. For instance, E. coli isolates from Northern California showed lower resistance to certain antibiotics like ceftiofur compared to the Northern San Joaquin Valley and Greater Southern California. We believe this difference is related to regional variations in management practices and how antibiotics are used, especially for mastitis prevention and treatment. It's noteworthy that some dairies in Northern California didn't use antibiotics for mastitis treatment or prevention, which contributed to lower AMR in those areas. This really suggests that management practices that reduce the overall need for antibiotic treatments can play a significant role in bringing down AMR. The seasonal variations we observed, with higher resistance often seen in winter for E. coli isolates, could be attributed to weather conditions that favor bacterial growth and increase disease, potentially leading to more antibiotic use.
The Dynamics of Antibiotic Treatment and Resistance
Our in-depth study on the dynamics of ceftiofur resistance further highlights the impact of antibiotic treatments. We found that while systemic ceftiofur treatment leads to a rapid increase in resistant Enterobacteriaceae, these levels typically return to pre-treatment baselines within a few days. However, populations of sensitive bacteria can remain suppressed for a longer period. We even observed a cyclical re-emergence of resistance, though at diminishing levels, possibly due to complex interactions within the gut bacteria. These dynamics are critical for us to consider for future AMR surveillance and when designing treatment strategies.
The Path Forward: Stewardship and Smart Choices
In summary, our research emphasizes that while we weren't focused on entirely new non-antibiotic products, the most important "alternative" approach to combating AMR on our dairies is through robust antibiotic stewardship and judicious use. This means making informed decisions in consultation with your veterinarians, selecting antibiotics based on known resistance patterns, adhering strictly to approved drug labels and treatment protocols, and, crucially, implementing best management practices that reduce the incidence of diseases requiring antibiotic intervention in the first place. By doing so, we can help ensure that the antibiotics we rely on for animal health remain effective for generations to come.
A Delicious Barbeque Sauce from Tomato Powder (September 2025)
Monica Gross, UC Master Food Preserver Online Program Volunteer
Image Credit: Monica Gross, 2025.
Can you imagine an activity that allows you to experience all of your five senses? Cooking and preparing food are just such activities! Allow me to walk you through an experience that involved seeing, hearing, touching, smelling, and tasting.
Using tomato powder to make a delicious barbeque sauce delighted all of my senses. The process involved reconstituting dehydrated tomato powder and adding a variety of ingredients to transform it into a tasty sauce that can be used for any barbeque entrée or side dish. I added all of the ingredients, except the cornstarch, to a saucepan and mixed them together with a whisk. Initially I saw that that sauce was thin and orangish colored (Fig. 1). Upon completion, the color changed to a darker, deeper reddish color (Fig. 2). The consistency also changed as it cooked. I used my sense of touch to feel that it was thickening. I could “feel” it changing as I stirred with the whisk (Fig. 3). I brought the sauce to a boil, then simmered about 20 minutes. I listened carefully and could hear the gentle “pop-pop” of the simmer alongside the louder drone of the range hood. When the sauce was almost complete, a pleasing aroma filled the air as I smelled its delightful scent. Of course, the ultimate test of the recipe was the tasting of the final product. Licking the spoon after the sauce was placed in its storage container was the highlight of the cooking experience. The satisfying conclusion was that the sauce is delicious and will make my family happy during dinner tomorrow night!
BBQ Sauce Made with Tomato Powder
Ingredients:
½ cup tomato powder
1 ½ cups water
1 cup brown sugar
1/3 cup apple cider vinegar
1 Tablespoon Worcestershire sauce
3 Tablespoons lemon juice
1 Tablespoon ground mustard
½ Tablespoon onion powder
1 Tablespoon smoked paprika
½ Tablespoon salt
1 teaspoon pepper
½ teaspoon garlic powder
1 Tablespoon cornstarch “slurried” in 1-2 Tablespoons cold water
Instructions:
- Mix all ingredients except the cornstarch in a saucepan and stir/whisk together.
- Bring to a boil and simmer for approximately 20 minutes until desired thickness is reached.
- For a thicker sauce, remove the pan from the heat and whisk in the cornstarch slurry. Return the pan to the heat, bring back to a boil, and simmer until the sauce thickens.
- Store sauce in clean container(s) in the refrigerator for up to a week or freeze in freezer-safe containers, leaving appropriate headspace, for up to six months.
For more information see:
- Last month’s Save the Season Newsletter explains how to make tomato powder - Making and Using Dehydrated Tomato Skins (August 2025) | UC Agriculture and Natural Resources
- Reconstituting Tomato Powder 334013.pdf
What’s the buzz? -- Infants and Honey (September 2025)
Kirsten Hansen, UC Master Food Preserver Online Program Volunteer
Image Credit: Kirsten Hansen, 2025.
I recently gave birth to my first child, which means that I left behind the many recommendations about what pregnant people should and should not eat and have entered the world of what infants should and should not eat. One very common recommendation is that infants under a year old should not eat honey, due to the risk of infant botulism. However, I was curious about what this meant: no spoonfuls of honey, of course, but what about baked goods with honey, or preserves that use honey as an alternative sweetener? I decided to do more research.
What is botulism?
Botulism is a serious disease caused by a neurotoxin created by the bacterium Clostridium botulinum. C. botulinum occurs naturally as inactive spores that are ubiquitous in the environment, including soil, water, freshwater and marine sediments, the surfaces of fruits and vegetables, and in seafood. The spores themselves do not make people sick. Under certain conditions, however, the spores can germinate into vegetative bacterial cells and produce botulinum toxins, neurotoxins that attack the body’s nerves, causing muscle paralysis, difficulty breathing, and in severe cases, death (University of California Agriculture and Natural Resources, 2018, p. 5-3). Botulinum toxins (there are several variants) are among the most poisonous biological substances known.
Home food preservers worry most about foodborne botulism, in which the neurotoxin is produced by C. botulinum under the following conditions:
- Anaerobic (low or no-oxygen) environment
- Low acid (above 4.6 pH)
- High moisture
- Temperature between 40° - 120°F
- Low salt (Centers for Disease Control, 2024)
These are exactly the conditions inside a low-acid (i.e., pH < 4.6) food product in storage in a canning jar. If C. botulinum spores are present in a low-acid food product (given their prevalence, we must assume they are) and are not completely destroyed by high-temperature processing (i.e., pressure canning), the spores can germinate into active vegetative cells and generate botulinum toxins. The risk of foodborne botulism is eliminated when safe food preservation techniques are used, which is why the Master Food Preservers program puts so much emphasis on using safe, tested recipes and adhering to the specified processing times for preserving food.
Infant botulism
In the U.S., 200 - 250 cases of botulism are reported annually, of which 60 - 70% involve infant botulism (CDC National Botulism Surveillance System). Infant botulism is completely different from the foodborne botulism that affects adults and older children. Infant botulism typically affects infants under 12 months of age but is most common in those under 2 months of age. It occurs when infants ingest C. botulinum spores that then germinate, colonize, and produce neurotoxin within the infant's intestinal tract. (Clostridium Botulinum & Botulism | Food Safety and Inspection Service, n.d.). It is not definitely known why infants are more susceptible to the germination of C. botulinum spores and subsequent proliferation of the bacterium in the gut than are healthy adults. In the past, the increased susceptibility of infants was thought to be due to the higher pH of infant gastrointestinal (GI) tracts than in adults, but it’s not clear that’s true. The current leading hypothesis is that infants lack the robust microbial community present in the GI tracts of healthy adults. C. botulinum is not a strong competitor for food resources in the presence of an established microbial community, which infants lack. This lack of competitors is thought to allow C. botulinum to proliferate. In short, infants’ gastrointestinal (GI) tracts are not mature enough to fight off the inactive C. botulinum spores and bacteria that adults and older children can handle, and the neurotoxin can develop from the bacteria that emerge as the spores break dormancy. The U.S. Food and Drug Administration, the Centers for Disease Control and Prevention, and the American Academy of Pediatrics all recommend that honey not be fed to infants under one year of age, and that fruits and vegetables should be washed before consumption (which, frankly, is good advice for everyone!) (Clostridium Botulinum & Botulism | Food Safety and Inspection Service, n.d.)
Unfortunately, most cases of infant botulism do not have a clear origin. Recent research has found that most cases of infant botulism occur when infants swallow microscopic dust particles that carry C. botulinum spores. (Harris & Dabritz, 2024, 305). Honey is a known but secondary cause. (California Department of Public Health, 2022). Although, we can’t stop infants from swallowing tiny bits of dust, we can refrain from feeding them honey, so the recommendation to avoid honey under a year old stands.
What about pasteurization?
Raw honey is not safe for infants, but I wondered about pasteurization. Unfortunately, the process used by the honey industry to pasteurize honey is not enough to deactivate the spores that can ultimately result in the production of botulinum neurotoxins. Per Romeo Toledo, a food scientist with the University of Georgia College of Agricultural and Environmental Sciences, honey must be heated to 250°F for a minimum of three minutes to destroy C. botulinum spores. Because this temperature burns honey and changes the flavor, industrial honey is heated to a lower temperature for longer. This destroys molds and common yeasts, but not C. botulinum spores. (Omahen, 2002). I found an article from 2002 that described a new sterilization technique developed by the University of Georgia that destroys C. botulinum spores (Omahen, 2002) but I could not find any information about the degree to which the honey industry has adopted the new procedure. Without further evidence, pasteurized honey must be considered unsafe for infants.
What about home preserved foods and baked goods?
Home preserved foods rely on several methods to make them safe. High-acid foods (below pH 4.6), such as pickles and jams, can be processed in a hot water canner because the acidity, heat, and processing time combine to destroy food spoilage organisms. However, hot water canners only reach temperatures of 212°F (the boiling point of water at sea level, boiling temperatures decrease with increasing elevation), but C. botulinum spores survive to temperatures of 240°F. Although C. botulinum spores can survive the hot water canning process, their growth is inhibited by the acidity and/or low water activity of foods that can be safely processed in a water-bath or atmospheric steam canner (University of California Agriculture and Natural Resources, 2018, p. 4-2). This means they are safe for adults, but not for infants! Items such as jams that use honey as an alternative sweetener should not be fed to infants.
Low-acid foods (above 4.6 pH), such as vegetables, soups, and meats, must be processed in a pressure canner, which uses pressure to heat food above 212°F. In this case, heat and time (but not necessarily acid) combine to make foods safe. At sea level, foods that are processed in a pressure canner at 10 psig reach 240°F, the temperature at which C. botulinum spores are destroyed. (University of California Agriculture and Natural Resources, 2018, 5-2). (Because water boils at a lower temperature at higher elevations, higher pressures are needed to reach spore-inactivating temperatures if one is canning in a location more than 1000’ above sea level.) Nevertheless, as discussed above, such high temperatures burn honey and ruin the flavor, so pressure canning is not a suitable method for honey preservation.
I could not find specific information about honey in baked goods, but most baked goods never reach temperatures above 212°F, so C. botulinum spores can survive. Recommendations from the American Academy of Pediatrics and the Center for Disease Control advise avoiding all forms of honey, including in baked goods and industrial products such as cereals for infants under a year old (Stanford et al., 2013).
In conclusion
Honey is safe (and delicious!) for adults and children over a year old. However, due to the risk of infant botulism it should be avoided in all forms for infants under a year old. All fruits and vegetables should be thoroughly washed before consumption.
References
Abdulla, C., Ayubi, A., Zulfiquer, F., Santhanam, G., Ahmed, M. A. S., & Deeb, J. (2012, July). Infant botulism following honey ingestion. BMJ Case Rep ., 2012(bcr1120115153). PubMed. 10.1136/bcr.11.2011.5153
California Department of Public Health. (2022, March). Frequently Asked Questions (FAQs) About Infant Botulism. California Department of Public Health. Retrieved July 20, 2025, from https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/FAQs_English_Updated_March2022_ADA.pdf
Centers for Disease Control. (2024, April 18). About Botulism | Botulism. CDC. Retrieved July 20, 2025, from https://www.cdc.gov/botulism/about/index.html
Centers for Disease Control, National Botulism Surveillance System. Case Reporting data for 2017 - 2021. https://www.cdc.gov/botulism/php/national-botulism-surveillance/index.html. Retrieved July 27, 2025.
Food Safety and Inspection Service, U.S. Department of Agriculture. (n.d.). Clostridium botulinum & Botulism | Food Safety and Inspection Service. Food Safety and Inspection Service. Retrieved July 20, 2025, from https://www.fsis.usda.gov/food-safety/foodborne-illness-and-disease/illnesses-and-pathogens/botulism
Harris, R. A., & Dabritz, H. A. (2024). Infant Botulism: In Search of Clostridium botulinum Spores. Current Microbiology, 81(10), 306. PubMed. https://doi.org/10.1007/s00284-024-03828-0
Omahen, S. (2002, September 05). New Process Makes Honey Safe For Infants. CAES Newswire. Retrieved July 20, 2024, from https://newswire.caes.uga.edu/story/1460/safer-honey.html
Sanford, M. T, et al. (2013), “Infant Botulism and Honey: ENY-128 AA142, 6 2013. EDIS 2013(6). Gainesville, FL. https://doi.org/10.32473/edis-aa142-2013. Retrieved July 27, 2025.
University of California Agriculture and Natural Resources. (2018). Fundamentals of Consumer Food Safety and Preservation: Master Handbook. UC Master Food Preserver Program. 9781627110211
Spotlight: Jadrian Johnson, Class of 2025 MFP Volunteer (September 2025)
Jadrian Johnson UC Master Food Preserver Online Program Volunteer
County of residence: Los Angeles
Image credit: Jadrian Johnson, 2025.
There is a unique alchemy in food preservation, a practice that feels just as much a form of time travel as it does domestic science. Within a simple jar, we can seal not just the fleeting sweetness of a summer peach, but the echoes of the hands that harvested it, the stories shared over a bubbling pot, and the enduring spirit of a family. For me, this craft is a conversation with my history, and its language was taught to me by two formidable women: my mother-in-law, Patti, and my Grandma Ruth.
My connection to my family’s Nebraska roots is a flavor that collapses time, reaffirmed with every spoonful of the grape jelly Patti sends at Christmastime. It’s a preserve made from an heirloom grapevine her own mother planted generations ago. It’s a taste of heritage, a direct throughline to the matriarchs who kept this tradition thriving. My other North Star was my Grandma Ruth, whose basement was a veritable family museum. Amidst the ghosts of my stylish grandparents’ vintage clothing and a guest room corner that was a perfect time capsule of seventies decor, I found my real treasures. There, in the coolest part of the cellar, stood two floor-to-ceiling cabinets, a library of captured seasons. Jars of home-canned green beans, tomatoes, pears, applesauce, and more stood like jewels on the shelves, a testament to her skill and a vibrant promise of bounty against the monochrome of a Nebraska winter.
With such profound inspiration, it seems inevitable I would find my way to becoming a canner. My own kickstart, however, was fired up in the summer of 2020. As the world rose up to protest profound social injustice, I felt a desperate, visceral pull to join the chorus on the streets. But being immunocompromised, I was warned by my doctors to stay home and not risk COVID-19 infection. Faced with the choice of safety over solidarity, I felt sidelined. Instead of succumbing to helplessness, I resolved to redirect that fire. I traded the pavement for the pantry and brought the protest into my kitchen.
My small Los Angeles backyard, bursting with the striking colors of nectarines, kumquats, and apricots, became my staging ground. I cranked up my kitchen and taught myself to safely harness the wild alchemy of fruit, sugar, and pectin, offering these jars as gifts to folks who made donations to social justice organizations—groups fighting for food security and nutritional education in underserved communities. That summer, this quiet act of creation, fueled by the legacies of Patti and Ruth, helped raise nearly $10,000 for charities.
From a bountiful basement and a legacy grapevine to my own California kitchen, the thread continues. It is a profound reminder that preservation is always an act of love, a way to honor the past while actively building a more just, more equitable, and infinitely more delicious future. I’m proud to be part of the UC Master Food Preserver class of 2025 to help empower others to continue these traditions in safe and sustainable ways!
*Article revised 10/15/2025
