Food Microbiology- Meat and Poultry

FDA has approved the use of

0.4% CO for meat packaging Package with 0.4% CO, 20% CO2 and the rest N2 you will get a bright red product with low microbial counts, good flavor and tenderness Problem: acceptability of CO in product by consume

Non-intact

1) visually intact but processed by mechanical tenderizing, injection with marinades, vacuum applied marinades, addition of proteolytic enzymes Protolytic enzymes are a way to tenderize and make the meat a non-intact food 2) reformed: ground, chopped, flaked, minced and they do not look like intact product Need to cook these to higher temps: 71.1 C (160 F) to kill Salmonella or E. coli O157:H7

E. coli O157:H7 and S. aureus:

1200 degree-hours when temp is lower than 90 F 1000 degree-hours when temp is 90-100 F 900 degree-hours when temp is > 100 F

beef processors

18% of beef products are tenderized mechanically or injected with solutions Beef steaks and roasts are blade tenderized Beating on meat relaxes the proteins Becomes non-intact Non-intact beef: numerous recalls for outbreaks of E. coli O157:H7 (mechanical tenderizing) If meat is not cooked well enough in the middle something like E. coli survives. Cook steaks to rare (internal temp 60C or 140F) or medium rare (65C or 149F) internal foodborne pathogens may survive Mechanically tenderize a steak: 3-4% of surface microbes can be translocated to the center (E. coli O157:H7) and then can be cut into smaller steaks

Thermal processing of sous vide products:

70 C for 100 mins or 90 C for 10 mins Main concern is C. botulinum, don't want spores to germinate and make toxin

Microbial load of hide of beef cattle:

8-10 log CFU/cm2 for APC 6-8 log CFU/cm2 for TCC 5-7.5 log CFU/cm2 for E. coli

Food safety and inspection service (FSIS) looks at

APC (aerobic plate counts) and TCC (total coliform counts) and then E. coli after evisceration and chilling With pig carcasses see a reduction in microbial load from 5.81 log cfu/cm2 to 0.67 log cfu/cm2 Salmonella at evisceration is 69.6% but at chilling is down to 2.7%

most identified mesophiles

Acinetobacter baumannii, Buttauxella, Serratia:

Feedlot air

Bacillus, Corynebacterium, Paenibacillum, Micrococcus and the molds such as Alternaria, Cladosporium and Penicillium upwind: 1-2 log cfu/ml from feedlot soil Downwind: 1-4 log cfu/ml from feedlot soil

GI tract:

Bacteriodes, Prevotella, Faecalbacterium, Bacteriodeles, Ruminococcus, Clostridium, and Succinovibrio Dairy and beef cattle have different microbial diversity Higher numbers of Arthrobacter, Asteroleplasma, Bifidiobacterium, Collinsella, Lactobacillus, Olsenella, and Propionobacterium are found in beef cattle GI

hides removed subsequent to exsanquination hide removal after exsanguination and hide is pulled while being rolled down the carcass, this can create aerosols if hide is wet so microbes can be deposited on equipment or the carcass itself

Beef

Numerous clostridium found:

C. braunii, C. beijerinckii, C. lithuseburense, C. algidicarnis, C. algidixylandolyticum, C. estertheticum, C. frigidicarnis, C. gasigenes All are non-pathogens and are simply spoilage organisms Germinate and grow causing spoilage at 2 C or lower in meat near neutral pH Meat undergoes proteolysis: muscle softening, H2S production, offensive odors meat goes from pink/red to green organisms are not pathogenic but food is organoleptically unacceptable Organoleptic→ looking at taste, smell, visual, and touch found in US, Europe, South Africa, New Zealand

Where these pathogens are found

Campylobacter: poultry E. coli O157:H7: ground beef, leafy greens, raw milk Listeria monocytogenes: deli meats, unpasteurized soft cheese, produce Salmonella: eggs, poultry, meat, produce Some salmonella can be found in the yolks of eggs Outbreaks seen in rich ice-cream Raw cookie dough Vibrio: raw oysters and clams, crabs, shrimp Norovirus: sandwiches, salads Toxoplasma: meats Viral pathogens: worried because they often come from contaminated food handlers E. coli O157:H7, STEC, Salmonella, Campylobacter are already on the meat during processing Listeria: ready-to-eat (RTE) processed meats and poultry (deli)

naturally found in Oregano and is antimicrobial

Carvacarol

DFD and PSE meats:

DFD- DFD has a pH > 6.0 while PSE has pH < 5.3 (normal muscle pH is 5.5) rate of spoiling due to microbial growth is different Lack of glucose, high pH: rapid degradation of amino acids by Pseudomonas and you get spoilage at lower cell densities DFD: vacuum packaging or MAP: spoilage, developing green discoloration due to Serratia liquifaciens and Shewanella putrefaciens with an outgrowth of LAB at high pH green is hydrogen sulfide formation by Shewanella and hydrogen sulfide reacts with myoglobin in meat PSE- spoilage dictated by storage temp and packaging Pseudomonas from aerobic packaging and LAB from MAP/anaerobic Ground beef (comminuted product): spoils faster than intact meats contamination and cross contamination of surfaces, microbial spreading during grinding, release of fluids and nutrients during grinding

Antibiotic resistance of foodborne pathogens (being seen much more often)

E. coli O157:H7 and STEC: early isolates were 97% sensitive to most antibiotics Used E. coli O157:H7 and E. coli O157:NM: 24% resistant to at least 1 antibiotic and 19% resistant to 3 or more Two E. coli O157:NM: resistant to 6 antibiotics: ampicillin, kanamycin, ticracillin, tetracycline, sulfasoxazole, streptomycin E coli O103 (152 isolates): 37% resistant to sulfamethoxazole Does not produce shiga toxins Sulfamethoxazole is the most common sulfa drug. E coli O26: 2.4% resistance to sulfamethoxazole Salmonella (non-typhoidal): 1.2 million illnesses/yr, medical cost $365 million 3% resistant to ceftriaxone 5% resistant to 5 or more antibiotics Seeing more infections with Salmonella typhimurium DT104 (multiple drug resistance) Oct 2018: S. infantis from raw chicken: 92 sick, 21 hospitalized (multidrug res) Summer 2018: S. reading from raw turkey, 90 sick, 40 hospitalized

foodborne pathogens

E. coli O157:H7, other STEC, Salmonella, Camylobacter, Yersinia enterocolitica, Listeria monocytogenes

Fungi in meats and poultry

Fungi come from animal confinement buildings such as air or floors of slaughter houses Penicillium, Cladosporium, Aspergillus Fresh and refrigerated meats/poultry Beef/pork: Cladosporium, Geotrichium, Mucor, Rhizopus, Sporotrichium yeasts: Candida and Torulopsis poultry: Alternaria, Aspergillus, Cladosporium, Geotrichium, Mucor, Rhizopus, and Penicillium yeasts: Candida, Cryptococcus, Debaryomyces, Pichia Rhototorula, Sacchromyces, Yarrowia Debaryomyces hansenii is important in the production of dry cured Iberian ham Spoilage of meat: Yarrowia lipolytica, Rhodotorulis, Cryptococcus: they cause discoloration of meat, sliminess, and off flavors Chilled meat: black spot spoilage Cladosporium herbarum, Penicillium hirsutium, Aureobasidium pullulans Dry-cured, fermented sausages and meats black spot: Cladosporium oxysporium and Penicillium both of these can tolerate large salt concentrations

Antimicrobial interventions:

HACCP (hazard analysis and critical control point): used to deal with E.coli O157:H7, STEC, Salmonella, and Campylobacter 3-5 treatments applied at different stages of production or processing this is a multiple hurdle approach Hide: wash with acid spray, alkaline spray, or hydrobromous acid spra Pre or post evisceration: hot water, saturated steam, organic acids, acidified sodium hypochlorite, hyrobromous acid, peracetic acid NaOCl- bleach, sodium hypochlorite HBr- hydrobromic acid Chilled carcasses, subprimals, trimmings: add organic acids such as lactic acid, citric acid, acidified sodium hypochlorite, PAA, or lauric arginate PAA- peroxyacetic acid H2O2+- acetic acid LAE Lauric acid Arginine Ethanol Plasma membrane =SAL -EC -Campy Staph Clos Listeria Hot water, steam, acetic acid or lactic acid can reduce bacterial numbers by 1 to 3 logs on a carcass Decontamination agents may be approved if they meet the following: a. generally recognized as safe

Microbial Loads on Beef

Hide: 7 log cfu/cm2 while on dehided carcass 2 log cfu/cm2 or more (fig 6.3) Evisceration increases the microbial load Decrease the microbial load by treating carcass with antimicrobials carcass then hot water spray at 90 C then peroxyacetic acid spray to steam pasteurization These steps are NOT seen at all slaughter operations and these steps are based on space, capital investment and cost of operation

Food waste

In US, Canada, Australia, and New Zealand 3.5% lost during production 1.0% lost postharvest handling and storage 5.0% lost in processing and packaging 4.0% lost in distribution 11% lost in consumption Percentages are out of all beef being produced Distribution and consumption loss is due to food spoilage

Spoilage:

LAB causing sour off flavors, slimy exudates, and carbon dioxide In US: products getting more severe thermal treatment are gaining popularity mostly meat/poultry products that contain gravy or sauce 80-85 C for several hours in a vacuum pouch

Products exposed to the environment during slicing and packaging before thermal processing are at risk for

Listeria and spoilage organisms Many antimicrobial agents (salts of organic acids) are used to reduce Listeria in fully cooked RTE meats and poultry and can reduce C. perfringens outgrowth

Thermal treatments (pasteurization)

Listeria assumed to be on surface of product, increasing the surface temperature which will increase the safety of the RTE Hot water/steam: product is chilled, opened, packaged in vacuum bags and then exposed to heat Any purge (liquid expressed from the chilled product collected at the bottom of the package or between the film (package) and product surface requires longer heating times and minimizing purge helps in determining processing times and temperatures Product configuration is important in thermal processing time required to heat frankfurters that are packaged in a single layer is significantly different than double layers

Antimicrobial interventions: aimed at

Listeria monocytogenes mitigation strategies: control the organism in the environment eliminate listeria in the product (in-package treatments) prevent growth of listeria using antimicrobial agents or processes Physical methods: used to decrease Listeria in RTEs of meat/poultry heat treatments using steam, hot water spray, immersion or high pressure processing (HPP)

Other methods

Looking to evaluate the use of sorbates, benzoates, and propionates with RTEs of meat/poultry Looking at all-natural sources of antimicrobials: cane syrup (sugar) which ends up as lactic and acetic acid in foods Not to be confused with glucose syrup used for baking. This is the concentrated sap that comes from sugar cane. may also add hydoxides or carbonates concentrated lime or lemon juice as a source of citric acid cane sugar fermented to vinegar (acetic acid/diacetate) Popular trend is for the intake of lower sodium in prepared foods in foods have sodium phosphate and sodium organic acid + NaCl replace some of the sodium with potassium DO NOT replace all sodium with potassium because it will lead to bitter Taste

have greater thermal resistance and may survive treatment

Micrococcus and Enterococcus

Dried meat Products

Number of low aw foods implicated in foodborne illness outbreaks due to Salmonella and some STEC Jerky: Salmonella Montevideo and Salmonella kiambu in New Mexico process of drying led to problems Jerky production: Meat strips which are marinated Can have application of antimicrobial interventions (reduce number of microbes to safe levels) Surface application Lethality step Drying Post drying heating Handling

poultry processing operation

Online Preprocessing IOBW Pre chill Chilling Post chill dip Anti-microbial dip spray

Most used chemicals with poultry are:

PAA, cetylpyridium chloride (CPC), chlorine and to a lesser extent: chlorine dioxide, citric and lactic acid, bromium, and TSP (trisodium phosphate) Chlorine has been used for over 50 years because of the low cost and it is readily available Chlorine is added to immersion chillers and other large tanks Acceptable level of free residual chlorine is 50 ppm in bird washes and incoming potable water to chillers 5 ppm in reuse water Effectiveness of chlorine depends on: pH, organic matter in water, and contact time with bacterial cell High amounts of free residual chlorine the better but if it is too high then chlorine gas is released from immersion tanks Study using an inside-out bird washer: 50ppm of chlorine not effective against Campylobacter or Salmonella when contact time was 5 secs PAA: peracetic acid + hydrogen peroxide are added to water to produce both an oxidizer and an acid (peroxyacetic acid PAA at 85 ppm in chilling water reduced Salmonella levels on carcass by 92% and reduced Campylobacter by 43% Broiler carcass exposed to 1000ppm of PAA for 20 secs in postchilling immersion tank saw: decrease of 2.1 log cfu/ml of Salmonella and a decrease of 2.0 log cfu/ml of Campylobacter TSP: trisodium phosphate, spray of this used for brine rinses and a 12% solution is approved by FSIS problems: residual TSP on carcass can raise pH of immersion tanks to 11 which will reduce the effectiveness of other interventions such as chlorine now have wastewater with high phosphate thus needing additional treatment to prevent pollution CPC: cetylpyridinium chloride which is a quarternary ammonium compound (can be found in mouthwash) now approved to treat raw surfaces of poultry carcasses seen a 2.89 log cfu reduction of C. jejuni on chicken skin using 0.5% CPC

on cattle hides can increase following exposure to a dust cloud and during loading of cattle onto trucks

Populations of E. coli O157:H7 and Salmonella Salmonella more prevalent in wet seasons than dry Can also get microbes from soil/manure to hides

hide stays on until carcass chilled, operations such as scalding, dehairing and singeing can reduce microbial load

Pork

we see an increase in clostridal blown-pack, where temperature during shrink wrapping does not change temp of meat enough (still cool)

Post packaging heat shrink of vacuum packaged meats

Aerobic comminuted product:

Pseudomonas, Acinetobacter, Moraxella which are on the exterior and LAB on interior

Food borne pathogens: poultry

Salmonella enterica: more than 2500 serovars and can cause human disease Typhoidal : S. enterica typhi or paratyphi: enteric fever Nontyphoidal: salmonellosis: gastroenteric disease this is mostly what we see and the most important strains are S. enterica enteriditis, S. enterica typhimurium, S. enterica Newport, and S. enterica Heidelberg Broilers: S. enterica Kentucky, S. enterica enteriditis, S. enterica typhimurium and S. enterica infantis Acute gastrointestinal disease that included nausea, vomiting, abdominal cramps, diarrhea, and fever with the onset 4-72 hrs after ingestion of food or water, the illness can last up to 7 days and is noninvasive certain strains can cause a septicemia Salmonella: consumption of contaminated meat and eggs

Pathogens on poultry

Salmonella, Campylobacter, Staphylococcus aureus, Clostridium perfingens, and Listeria monocytogenes Salmonella and Campylobacter are the major players Listeria found most frequently in RTE poultry products

Abattoir

Slaughterhouse

Spoilage of processed meats: frankfurters, bologna, cooked or fermented sausage and lunch meats:

Slime: surface only and is due to yeasts, Lactobacillus, Enterococcus, Brochothrix thermosphacta Only on the surface Souring: metabolism of sugars to organic acids under casings or packaging film Greening: hydrogen sulfide production this may occur in nitrite cured meats in the presence of hydrogen peroxide which is not broken down by muscle enyme which has been inactivated Streptococcus and Leuconotoc Putrid spoilage: cured meats, Gram - psychrotrophs are inhibited by the low aw under refrigeration at low aw lactobacillus (MAP/anaerobic) and micrococci (aerobic) If glucose included in cured meats: slimy dextran layer from Leuconostoc dextran→ glucose polymer Dry cured meats: spoiled mostly by yeasts and mold due to the low aw , presence of nitrite or if smoked

Poultry Processing

Transportation and unloading: birds are loaded onto transport unit in a platic crate or steel crate containers quickly become contaminated by fecal matter and can spread to other birds (Campylobacter, Salmonella, E. coli) You should transport birds in a clean crate lined with single use paper liner Crates should be cleaned and disinfected before use Need to clean then disinfect: 2 stage process Shown that a high pressure jet spray with disinfectant (1 step) does NOT reduce the coliform level much Take a clean crate and submerge it in hot water (60-70 C) or in sodium hypochlorite (1000 ppm) get a decrease in coliform levels For Campylobacter: soaking crate, brushing, rinsing then application of disinfectant Birds are unloaded and hung on shackles and then "stunning" birds are unconscious prior to killing Do electrical stunning in water bath with saline and the birds are unconscious for 60-90 seconds Next is killing, where the neck is cut and allowed to bleed out New method of stunning using carbon dioxide or carbon dioxide/argon or nitrogen Wing flapping may occur during stunning Next step is scalding which is used to prepare the carcass for defeathering Scalding tanks 53.35 C for 120 s is known as soft scalding 62-64 C for 45 s is known as hard scalding Can get transfer of bacteria from carcass to carcass Next step is defeathering where you have a high speed rotary wheel with discs with rubber fingers to remove feathers (Can see this on an episode of Dirty Jobs with Mike Rowe) Next step is evisceration where edible and inedible viscera is removed the GI tract is exposed, fecal contamination possible with increase in Salmonella on carcasses Next step is chilling: reduce the carcass temp to below 4.4 C the time to get there should not exceed 4 hrs for birds <4 lbs, 6 hr for birds 6-8 lbs and 8 hr for birds >8 lbs Immersion chilling and air chilling

Parasites:

Trichinella spiralis (trichinosis), Sarcocystis spp (sarcosystesis), and Toxoplasma gondii (toxoplamosis) these are all in SWINE Toxoplasma can be in cat litter, extremely bad for pregnant women. Pregnant women should not change cat litter. BEEF: tapeworms (Taenia spp), Sarcocystis spp, and Cryptosporidium parvum

US vs Europe

US uses a hot box while Europe uses blast chilling (blast of cold air below 0 C) A decrease in microbial load is due to the amount of dehydration associated with the chilling process on the surface of the carcass More processors are adding antimicrobials to chilling water spray

Antimicrobial interventions to subprimals that will become non-intact beef product:

a)proper chilling b)decontamination of injection solutions during reuse c)antimicrobials in injection brines d)effective sanitation e)effective cooking

With beef, microbes on hide can be

aerosolized in processing plant when either using mechanical or manual removal If microbes are deposited on dehided carcass they are tough to remove and this includes E. coli O157:H7 and other STEC. Any microbial load on dehide carcass is due to contamination through aerosolization or handling by personnel

Modified atmosphere packaging (MAP):

atmosphere around meat is different from air, product is enclosed in some kind of barrier and then the atmosphere is modified MAP: you can either draw a vaccum or flush and fill with a gas mix most commonly used gases are: carbon dioxide, nitrogen, oxygen these are all found in air but with MAP you change the ratios of these

Fresh meat: poultry

aw = 0.99 and a pH of 5.5 - 6.5 with numerous energy sources such as sugars, amino acids, vitamins, minerals for bacterial growth Specific spoilage organisms (SSO) Ephemeral Spoilage Organism (ESO): Pseudomonas spp, Enterobacteriaceae, B. thermosphacta, and LAB oxygen availability is important with ESO vacuum packaging can extend shelf life

poultry features

best color stability is 100% carbon dioxide this is better than 100% oxygen, 100% nitrogen, or 25% carbon dioxide, 66% oxygen, 9% nitrogen

Production of ______ can be a problem with consumption of muscle food products

biogenic amines production of: histamine, putrescine, spermidine, spermine if found in foods can cause scombroid poisoning, severe allergic rxn biogenic amines produced by Enterobacteriaceae tyramine: Lactobacillus

Carnobacterium

both mesophilic and psychrotrophic

Campylobacter jejuni or C. coli:

can get vertical transmission to eggs and horizontal transmission during processing, can persist on carcass skin

Commercially sterile products:

canned products processed to inactive C. botulinum spores Canned meat products: stews, soups, gravies, sauces, chili, pasta containing products, sloppy joe, roast beef

Pasteurization:

cannot adequately destroy spores of C. perfringens, B. cereus, or C. botulinum

Study:

compared gas grill, electric skillet, and oven broiler: the oven broiler gave the most consistent inactivation of E. coli O157:H7 on intact or non intact meats 2.6 out of every 10 servings of intact steaks contain 1 or more E. coli O157:H7 3.7 out of every 10 servings for mechanically tenderized steaks

Meat pH affected by stress on animal:

dark firm dry (DFD) or pale soft exudate (PSE) glycolytic reserves and rate of cooling that determines microbes regardless of packaging type and chilled storage method

United States uses ______ for dry/fermented products

degree-hour concept combination of time and temperature to achieve a product pH of 5.3 during fermentation degree-hours of a process: number of hours at the process temperature multiplied by the degrees above 60 F

Microbial populations:

depends on processing system during slaughter and other unit operations

ooling protocols:

designed to minimize the possible germination and outgrowth of C. perfringens to less than 1 log They like the warmth from sitting out at room temperature too long

Chilling

does not reduce microbial load When you chill something you lose water. Chilling is the induction of dehydration

Psychrotolerant clostridia:

food spoilage in vacuum-packaged meats may cause surface spoilage or blown-pack spoilage psychrophilic,psychrotrophic,psychrotoleran

Low oxygen MAP:

fresh meat primals: 20-25% carbon dioxide and 75-80% N2 carbon dioxide most effective against gram negatives carbon dioxide is highly soluble in meat, so get carbonic acid, decrease in pH nitrogen has low solubility in fat and water no affect on microbial growth but does prevent aerobic bacteria from growing increased shelf life Problem with excluding oxygen: discoloration of product, the cherry red color of meat due to oxygen binding to hemoglobin and myoglobin To combat this problem of discoloration: it is known that very low levels of carbon monoxide (CO) (0.3-0.5%) can produce a bright red color in meat

Foodborne pathogens: dried and fermented meats

generally these foods are microbiologically safe But: Staphylococcus aureus and toxin production, has been seen in fermented sausage when pH was above 5.0 Dry salami: E. coli O157:H7 which shows the acid tolerance of this strain for salami: want to achieve a 5 log reduction of E. coli O157:H7 and a 6.5 log reduction in Salmonella

Cooking pork:

get a high temperature to kill the parasite Trichinella spiralis and you will loose moisture Causes trichonosis which are worms in bloodstream that can bury themselves in muscle or cause cysts in brain. Since it must be cooked to a higher temperature it will lose moisture and thus they need to be tenderized first

Campylobacter:

gram negative, mesophilic, spiral rod that requires microaerophilic conditions to grow and can easily multiply in poultry GI 2012: leading cause of bacterial gastroenteritis worldwide symptoms: 24-72 hrs after consumption of contaminated food and tends to be a self-limiting disease with diarrhea, cramps, fever dose size is 800 cfu some patients develop an autoimmune disease, Guillan-Barre Syndrome (20-40%) S19

Staphylococcus aureus:

gram positive, aerobic cocci commensal bacteria on skin and mucosal area of mammals some found in poultry produces an enterotoxin leading to GI distress poultry contamination occurs during processing by contaminated food handlers/workers have seen multidrug resistant strains in meat and poultry

Clostridium perfingens:

gram positive, anaerobic, sporeforming rod consumption of contaminated poultry products GI toxicoinfection, need to consume large quantities of organism >6 log GI tract the organism is spore that germinates to vegetative state and produces an enterotoxin leading to profuse, watery diarrhea C. perfingens: spores are important and they resist thermal processing and may be in final food product large quantities of poultry undercooked or poorly cooked or you have a low postprocessing cooling rate (too long, this is bad)

Listeria monocytogenes:

gram positive, facultative anaerobic non-sporeforming rod listerosis: flu-type illness in healthy individuals, in children, elderly, pregnant women, and other immunosuppressed the disease is a systemic infection that can mimic meningitis and lead to death, babies can be stillborn or manifest infection including whole body rash and can have permanent damage Listeria monocytogenes: psychrotroph and has a wide temperature growth range and can grow in the refrigerator (4 C) persists in cold, damp environments within poultry processing facilities, deli found in floor drains, refrigerators, freezers RTE poultry products of great concern zero tolerance rule: RTE of meat and poultry must have <1 cfu/25g in RTE

Spoilage

growth of nonpathogenic microbes in response to prevailing extrinsic conditions during processing, distribution, and storage

High oxygen or low oxygen MAP

high oxygen MAP: 70-80% oxygen and 20-30% carbon dioxide in headspace fresh meat will last 7-14 days with high oxygen MAP compared to 3-7 days with aerobic packaging must be careful because high oxygen will accelerate lipid oxidation better than aerobic, NOT AS GOOD AS VACUUM

Antimicrobial interventions: dried meats

immersion of strips in marinades containing acids, pH reduction agents and/or spices instead can add acidic calcium sulfate or acidified sodium chlorite Lethality step: increase product temp at high humidity for the correct time to kill Salmonella and E. coli O157:H7 need at least a 5 log reduction at this step for Salmonella and 3 log reduction for Listeria Recent research: using HPP on fermented products either before or after drying can meet regulation numbers for E. coli O157:H7 Genoa salami: HPP process, pH is 4.58, aw is 0.89, 600 Mpa, for 1-12 mins decrease pathogen levels by an additional 1.6 to 5 log for Listeria 4.7-5.8 log for E. coli O157:H7 1.9-2.4 log for Salmonella Store salami at 4 C for 28 days, further 3 log reduction of Listeria, 1.1 log reduction of E. coli O157:H7 and 1.7 log reduction of Salmonella This is before it goes on the shelf

More handling:

increased risk of contamination

Microbial growth influenced by intrinsic factors? extrinsic factors?

intrinsic- pH, water activity (aw ), competitive flora, nutrient composition, redox potential extrinsic-cold chain, packaging type, gaseous atmosphere, antimicrobial ingredient

Vacuumed packaged:

lactic acid bacteria

Blown-pack spoilage:

large amounts of gas distends packaging during refrigerated storage Produce a large amount of CO2 causing the package to expand Beef primal cuts, lamb, venison, cooked hot dogs, precooked turkey, and roast beef can show blown-pack spoilage which is sporadic because the contamination with spores is sporadic

RTE meats such as acidulated or fermented and dried salami, salt cured meat products, dried meat products

low aw and may have a pH < 5.0 Types of products: summer sausage (produced by acidulation) Salami, pepperoni, Thuringer, chorizo (fermentation and drying to some pH and aw) capricola, country ham, prosciutto (salt curing) basturma, beef sticks, jerky (drying)

Meat and poultry: antimicrobial interventions employed

low or high pH Oxidation high or low temperature antimicrobial chemicals packaging atmosphere (CO2 + N2 with high or low O2) If microbe present at packaging: came from harvest/processing steps from hide, GI tract, equipment surfaces

Pork processors

marinate meat with an injection of salt or phosphates to improve juiciness Becomes non-intact beef

For spoilage:

microbes must grow/survive antimicrobial interventions and grow during packaging, storage, and distribution

During harvest and further processing:

microbial contamination occurs

34 amino acid polycyclic peptide added to these fresh meats Bactriocin Made by Lactococcus lactis Good against gram positives (Listeria, Bacillus, Staph, Clostridium Good against spores Not good against gram negatives, has a hard time getting through the outer membrane Pioneered by the Japanese

nisin

Viral:

norovirus, hepatitis A, enteroviruses, these are acquired due to poor sanitation, cross-contamination from infected food handlers, surfaces or adequate cooking Norovirus→ cruise ships HEP A- Jaundice. HEP B and C are the bad ones. HEP B and D have been linked to liver cancer. HEP C is nasty because you can go 30 years without showing signs.

Chemical methods: decrease Listeria in RTEs

organic acids (lactic,acetic,citric) lauric arginate acidic calcium sulfate liquid smoke fractions All have minimal effects on product quality and can reduce but NOT eliminate Listeria One study: sodium lactate + disodium acetate had synergistic effect in inhibiting Listeria on RTE meat/poultry (industry uses this method)

Aerobic packaging:

overwrapping the fresh meat on a styrofoam tray with very high oxygen permeable films made of polyvinyl chloride this DOES NOT HELP much with microbial growth or increase shelf life enhance the attractive red color due to interaction of oxygen withhemoglobin and myoglobin must refrigerate and shelf life is 5-7 days

Fresh meat:

packaged under aerobic conditions on tray with plastic filmwrap (at retail) small portion anaerobic (vacuum packaging) Processing plant: packaged under MAP with vacuum, high or low O2 (intact meat) Fresh meat that is refrigerated: aerobic: Pseudomonas anaerobic or MAP: LAB

Poultry spoilage:

parts with skin have higher microbial contamination rate than beef or pork Spoilage: endogenous enzyme activity in muscle fecal microbes that produces: amines, sulfides, alcohols, aldehydes, ketones, organic acids Effects of spoilage include color, odor, texture, and flavor changes Intestines, skin, and feathers have spoilage bacteria and are introduced during processing

HPP:

pressures of 586 MPa have been used for treatment of meat/poultry RTEs minimal change is food quality order of effectiveness of HPP: high is gram - bacteria, medium is gram + vegetative bacteria, fungi and low is viruses and spores HPP: cell membrane damage, protein denaturation, enzyme inactivation does not generate much heat, only 3 C rise per 100 Mpa Can use on cooked ham, fish, and precooked meals HPP marketed as a natural alternative to chemicals and is being considered for E. coli O157:H7 in fermented sausages Have seen E. coli O157:H7 outbreaks in fermented sausages and in the US we require a 3-5 log reduction of E. coli O157:H7 is these products HPP can be used for some foods but in others it has detrimental effects on product color and texture New trend in US: raw meat dishes for pets (can get in Wegmans) processors use HPP to eliminate Salmonella, Campylobacter, E. coli O157:H7 and other STEC where meat color is not a major concern

25% of foodborne outbreaks are seen due to

recontamination of processed food products: insufficient hygiene 1.6% cross contamination 3.6% inadequate sanitation in processing and storage facilities 4.2% contamination of equipment 5.7% contamination of personnel 9.2%

Pork Processing

removed to processing facility where they are stunned and then the jugular is cut (bleeding), after which the carcass undergoes scalding, then singeing (decrease in microbial load) Scalding: immerse swine carcass in hot water (61 C) for 8-10 minutes and you may add surfactants to loosen hair follicles decrease microbial load of skin by 3 log cfu/cm2 Dehairing: recontamination, can have residual hair in equipment so the microbial load increased by 2-3 log cfu/cm2 Singeing: flame surface of skin at 1200 C for 15 sec which will decrease the microbial load Pig carcass is sprayed with water and brushed to remove singed hair, this is known as polishing and will result in an increase in microbial load Next is the evisceration process and can get fecal contamination when the distal colon/rectum is removed The next process is chilling for 18-24 hrs and depends on the volume of carcasses, you don't want the carcasses to touch (cross contamination)

Vacuum packaging:

removing air around the product then sealing it in oxygen impermeable barrier bags low oxygen, high carbon dioxide levels inhibit growth of bacteria, yeasts, molds increase shelf life Low oxygen: support the growth of psychrophilic and psychrotrophic anaerobic and facultative anaerobes such as: Brochothrix spp, Lactobacillus spp, Leuconostoc spp, and Carnobacterium spp most meat is stored and shipped this way at temps of 0 to -1.5 C

Processed meat product ingredients

salt, acidulants, spices, spice flavorings, flavor enhancers (MSG), antioxidants, water binders (phosphates, starch collagens), protein substitutes and enhancers (soy, corn, milk), curing agents (nitrates/nitrites), cure accelerators (erythorbates, ascorbates), sweetners (corn syrup, alcohols of sorbitol, sugars), dehydrated meat (stocks), and antimicrobial agents (salts of organic acids) The type of ingredient and proportion used will determine the type of microbe found in postprocessing contamination

Cold aerobic conditions:

spoilage by Pseudomonas psychotroph

Intact

steaks, roasts, chops age of the animal is important, the older the more chewy and less tender so processors will tenderize subprimals (smaller portions of meat) Any manipulation done, introduces microbes microbes are mostly on the surface mechanical tenderizing, injection with marinades, marinades added with applied vacuum you can get translocation of microbes from surface to the interior Meats not processed: can cook to lower temps and still be safe

Minced beef:

stored at 0, 5, 10, 15 C aerocially or modified packaging (MAP) MAP is 40% CO2, 30% O2, 30% N2 +/- oregano essential oil Found 266 lactic acid bacteria (LAB) Leuconostoc predominant aerobic storage at 5,10,15 C and MAP at 10,15 C Lactobacillus sakei aerobic at 0 C and MAP at 0,5 C Leuconostoc mesenteroides, Weisella viridescen, Lactobacillus casei, and Lactobacillus curvatos which were isolated sporadically over all conditions

Inactivation of microbes depends on

surface population, type and thickness of cut, internal temperature, temp and humidity during cooking, uniformity of temperature during cooking

Thermally processed meat products are

typically pasteurized and the process is designed to destroy: E. coli O157:H7, STEC, Salmonella, Campylobacter, Staphylococcus aureus, and Listeria monocytogenes Performance standard is: 6.5 to 7.0 log reduction (Table 6.6) Thermal processing should also reduce spoilage organisms

most foodborne illnesses of meat and poultry due to

undercooking, underprocessing, cross contamination or improper handling of cooked food Temp control very important with highly perishable foods (meat and poultry) Initial microflora: surface of hide, intestinal contents, processing environment, and personnel have both gram negative and gram positive microbes

Chemical, enzymatic, and microbial activities can result in

visual or olfactory changes in a product Oxygen is a major culpprit because it can oxidize which leads to things become rancid Enzymes can start chewing away at the fruit causing rot

Types of microbes are dependent on

weather and season with winter and rainy seasons having higher numbers than dry/hot seasons Geographical location important in ecology of foodborne pathogens such as E. coli O157:H7 and other STEC E. coli