MILK-BORNE PATHOGENS & PASTEURIZATION

What is is an important source of nutrition worldwide?

milk

What is the composition of milk? (general idk man )

◦ 87.7% water

◦ 4.9% carbohydrate (lactose)

◦ 3.4% fat (65% saturated, 29% monounsaturated)

◦ 3.3% protein (82% casein, 18% whey)

◦ 0.7% minerals (Ca, Mg, P, K, Se, Zn)

◦ Vitamins: important source of vitamin A,

riboflavin (B2), pantothenic acid (B5), cobalamin

(B12), vitamin D (fortified)

T/F •Early milk production was local (often near cities) but frequently unsanitary

True

Milk was a major vehicle for what THREE diseases?

tuberculosis (M. bovis),

brucellosis, and diarrheal diseases

T/F Milk went from a major source of infectious disease to one of the safest foods due to pasteurization and public health regulation

True

What was The 1850s scandal was a deadly public health crisis in New York City where cows, kept in filthy sheds next to distilleries, were fed toxic "swill" (industrial alcohol waste)?

Swill Milk Scandal

What did the swill milk scandal produce?

It created a yellowish, watery milk that dealers thickened with flour, eggs, and chalk, leading to an estimated 8,000 infant deaths annually, sparking the first major US food safety regulations.

Milk is ___ as it is synthesized in healthy

mammary gland

sterile

What are some ways that microbial contamination occurs during or after milking?

◦ Mastitis (localized) or systemic infection

spread into mammary gland

◦ Feces on udder from environment

◦ Contaminated by humans or

milking/processing equipment

Why is milk an excellent "propagative vehicle"?

◦ Due to nutritional content, is an ideal medium for bacterial growth

◦ High fat content protects pathogens from stomach acid

What is using heat to kill pathogens in raw milk?

Pasteurization

Who developed Pasteurization?

Louis Pasteur

T/F There is a risk of pathogen contamination in milk produced from healthy cows under sanitary milk conditions, therefore pasteurization is necessary

True

Pasteurization also destroys ___ ____ and enzymes that cause deterioration of milk and reduced shelf life

spoilage microbes

T/F Pasteurization does not meaningfully impact nutritional content ;

minor reductions in some vitamins like vitamin C occur

True

What FDA and USPHS agency sanitary regulation with provisions governing the production, processing, packaging, transportation, examination, labeling,

and sale of Grade "A" milk and milk products?

Pasteurized Milk Ordinance (PMO)

What is the purpose of the PMO?

to facilitate shipment and acceptance of milk and milk

products of high sanitary quality in interstate and intrastate

commerce

T/F PMO is a required adoption by states and localities

Fasle, recommended for voluntary adoption by states and localities

PMO requires that all milk should be from herds under what TWO USDA programs?

Tuberculosis eradication program, Brucellosis eradication program

Diagnosis of TB or Brucillosis must be done how?

Diagnosis of other diseases must be based on findings of licensed and accredited veterinarian

Grade A PMO Defines Dairy Hygiene Standards and Inspection Procedures, what are some of them?

◦ Construction and cleanliness requirement

◦ Protection of cows and milk from contamination

◦ Animal drugs & administration equipment—labels,

storage, records, directions for use, withdrawal periods

◦ Cleanliness of personnel; hand-washing requirements

How must raw milk be stored based on the Bulk Tank Cleaning and Refrigeration?

◦ Raw milk must be cooled to 45˚F w/in 2 hours of milking

What is the most common Pasteurization temperature/time used in the U.S.?

HTST (high-temperature, short-time)

What is the temperature and time for HTST (high-temperature, short-time)?

161ºF 15 seconds

What is the the most heat resistant pathogen in milk?

Coxiella burnetii

All pasteurized milk must be ____ after pasteurization except for UHT/aseptic milk which is sterile

refrigerated

What is the # bacteria that can grow and form

countable colonies on Standard

Methods Agar after being held at 32°C

(90°F) for 48 hours?

Bacteria Count

What is the # of colonies in a sample that grow and form distinctive countable colonies

on Violet Red Bile Agar after being held

at 32°C (90°F) for 24 hours?

Coliform Count

What is Determined by direct microscopic exam or by specific instruments?

Somatic Cell Count

Mastitis will increase ____ count in milk.

WBC

WBCs contain lipolytic and proteolytic

enzymes which do what to the milks content?

degrade fats and proteins and causes deterioration of milk.

What is the most common cause of milkborne disease, particularly associated with raw milk?

Campylobacter

In 1987, what agency banned interstate

sale/distribution of raw milk?

FDA

T/F State laws regarding raw milk sales intrastate vary; illegal in some states including Alabama

True

Study on raw milk (1993-2006 data) showed that raw milk caused a much (lesser/greater) number of outbreaks than pasteurized milk

greater

In the conclusions of these studies, what age had nearly half of the illnesses?

children

Stale laws resulting in increased avalibility of raw milk are associated with (more/less) outbreaks

more

What are the recommendations for raw milk?

- it is important to educate parents of the health risk that raw milk consumptions presents to children

- we need to give evidence based recommendations to public and policy makers in order to prevent illness

What are FIVE common pathogens in raw milk?

- Campylobacter

- Salmonella

- E coli O157:H7 (EHEC/STEC)

- Cryptosporidium

- Listeria monocytogenes

In 2024: The Los Angeles County Department of

Public Health said Thursday that it is investigating two cases of H5N1 bird flu in

____ that consumed recalled raw milk from

Raw Farm LLC.

cats

If you are on a dairy farm, what can be a signs that your cattle may have H1N1?

if there are cats on the farm and they suddenly die

What is the consistency of H1N1 milk?

thick and creamy yellow

The FDA is confident that pasteurization is effective at inactivating ____, and that the

commercial, pasteurized milk supply is safe.

H5N1

What agency recommends that dairy producers segregate clinically ill cows from the rest of the

milking herd.

USDA

What agency recommends dairy processors not use milk from infected cows in the

production of raw milk products, such as raw milk cheese, and reminds manufacturers that

heat treating or pasteurization are both effective measures that inactivate H5N1.

FDA

What is used to vaccinate heifers for Brucellosis and can rarely be shed in milk

Strain RB51

What disease do you use Strain RB51 in?

Brucella

If you come into contact with Brucella, what is the protocol that follows?

21 days of post-exposure prophylaxis (PEP) + 6 months of

symptom watch

T/F Globally, there is no PMO, and there are few disease elimination programs that are followed

internationally.

True

Dairy products (are/are not) pasteurized in most places

are not

What is the greatest public health measure to reduce brucellosis in people?

pasteurization of dairy

Most of the Brucellosis cases in the US are caused how?

illegally imported unpasteurized

dairy products from Mexico

In 1900, what was the leading cause of death in the US?

TB

____ of milk broke the cycle of

transmission and eliminated spread of bovine TB in people in US

Pasteurization

Campaign to eliminate _ ____ was a major

incentive for the establishment of veterinary

services in many countries worldwide

M. bovis

What are some sources of contaminants in milk?

◦ Environmental: water, soil, air

◦ Feed contamination

◦ Direct application to animal or barn

◦ Contamination of milking equipment

What pesticide can affect milk?

Organochlorines

What replaced Organochlorines as a pesticide?

Organophosphates

How does milk become infected with Organochlorines?

◦ Via feed feed or direct application

What does Organochloride cause in humans and lab animals?

acute neurologic issues; lab animals show liver

cancer, neonatal mortality

What pesticide is now banned in the US?

Organochlorines

What does the label of Organophospahtes say?

do not use products labeled

for beef cattle or non-lactating dairy cattle in lactating cows

What is the tolerance level in milk of OP?

0

In early 1973, what TWO things were produced at the same manufacturing plant 10-20 fifty-pound bags of PBB were sent to Michigan Farm Bureau Services by accident & were used in feed mills to manufacture feed?

PBB (fire retardant) and magnesium oxide

Due to the mix up at the Michigan plant, what happened?

Mix-up discovered in April 1974, and PBB had already entered food chain

through dairy products, beef products, and contaminated swine, sheep,

chickens, and eggs

What THREE things resulted from this mix up?

30,000 cattle, 4500 swine, 1500 sheep, 1.5 million chickens were

destroyed

◦ 800 tons of animal feed, 18,000 lbs of cheese, 2500 lbs of butter, 5 million eggs, 34,000 lbs of dried milk products destroyed

◦ 9 million people exposed; low PBB levels in humans tested

What are the clinical signs of PBB?

nausea, abd pain, joint pain, fatigue, derm conditions (

What fungus produces Aflatoxins?

Aspergillus spp.

Where does aflatoxins infect?

contaminants of feeds and foods

including corn, rice, sorghum, and peanuts

What is the carcinogenic form of Aflatoxins?

B1

T/F Aflatoxins are activated by cytochrome P450s in the liver and are hepatotoxic (chronic or acute illness)

True

T/F Dairy cattle given feed with aflatoxin excrete aflatoxin metabolites in milk

True

What are some common recalls due to aflatoxins?

Pet food recalls, some human food recalls (peanut butter)

How do you prevent Aflatoxins?

- purchase feed from reputable persons and companies experienced in aflatoxin prevention

- Store feed at proper moisture levels.

- Minimize dust accumulation in milling and mixing areas

- Check feed storage bins for leaks.

- Implement effective rodent and insect control programs in grain storage areas.

What should you do to milk collected from cows on antibiotics?

discarded or collected separately

What do you need to make sure that you do with regards to Ab and milk?

Adhere to withdrawal times and follow labels

What does the FDA say about antibiotics and milk?

FDA requires that milk contain NO detectable antibiotics

Why does the FDA requires that milk contain NO detectable antibiotics? (3)

◦ Potential severe allergic reactions (penicillin)

◦ Development of antibiotic-resistant pathogens

◦ Inhibit fermentation for cheese or yogurt

What are some things you can do to test for antibiotic residue?

◦ Driver takes sample before accepting milk onto truck

◦ Each truck load is tested before unloaded at processing plant

◦ If antibiotic residues found, milk is discarded and individual farm

samples are tested to find source

◦ Regulatory action is taken against farm with positive antibiotic test

What was a a synthetic chemical, was added to milk and baby formula and is used as a flame retardant and a polymer in manufacture of cooking utensils/plates?

Melamine

Melamine has high ____ content which gives a false high reading of protein content

nitrogen

What was the result of Melamine, a synthetic chemical, was added to milk and baby formula?

◦ Resulted in 294,000 infant/child illnesses with renal

issues

◦ 52,000 hospitalized, 6 died

◦ Led to passage of regulations and laws