Commodity Microbiology – Meat and Poultry PDF

Commodity Microbiology – Meat and Poultry ENH 333 – Introduction to Food Hygiene Lecture 6  Fresh Meat and Poultry Fresh meat and poultry are amongst the most perishable of all products Meat/poultry are good growth media with high moisture and nutrient content...

Commodity Microbiology – Meat and Poultry ENH 333 – Introduction to Food Hygiene Lecture 6  Fresh Meat and Poultry Fresh meat and poultry are amongst the most perishable of all products Meat/poultry are good growth media with high moisture and nutrient content – Microbiologists still use a variety of meat extracts to grow cultures Internal tissues of both red meat and poultry are essentially sterile prior to slaughter – unless the animal is diseased However, fresh meat and poultry are contaminated during the slaughter and preparation processes  Fresh Meat and Poultry Sources of contamination: – The stick knife (if not sterile) – The hide / skin / feathers – The GI tract (if punctured) – Handlers – Containers / equipment – The storage environment – The lymph nodes  Fresh Meat and Poultry Factors affecting tissue invasion: – Load in the gut of the animal/bird – Physiological condition prior to slaughter – Method of killing and bleeding – Rate of cooling Intrinsic and extrinsic parameters that allow and support microbial growth – Intrinsic = high aw, mid-range pH, high nutrients, high surface O/R potential, and no biological structures or antimicrobials – Extrinsic = main factor is temperature of storage – determines which organisms can dominate and cause spoilage  Fresh Red Meat During large animal slaughter (e.g. cattle, pigs), animals should be well rested and not stressed prior to slaughter – Stress causes glycogen to be released into the bloodstream, causing less lactic acid to be produced after slaughter, affecting meat quality The animal is then stunned, hoisted up by the hind legs, and exsanguinated by slitting the jugular vein with a stick knife The hide is removed and the carcass is then eviscerated before moving onto further processing Specific steps differ by animal (e.g. cattle, pigs, lamb) Various methods are used during slaughter and processing to reduce the bacterial load (e.g. trimming, sprays/washes) Fresh Red Meat  Meat Contamination Ground meat tends to have higher levels of contamination compared to intact meat cuts – Ground meat can come from trimmings from various cuts – the excessive handling of cuts of meats prior to grinding increases counts – Greater surface area – increasing aerobic growth – Contamination from improperly cleaned grinding equipment, knives, and storage utensils – One heavily contaminated piece of meat will contaminate the whole batch, as they pass through the grinder Mechanically-tenderized meats (e.g. steaks) also have higher risk due to pushing of external contamination inwards – On May 21, 2014, Health Canada published an amendment to the Food and Drug Regulations in Canada Gazette Part II that requires any mechanically tenderized beef (MTB) sold in Canada to be labelled as such, including with safe cooking instructions.  Video: Mechanical Tenderizing https://www.cbc.ca/player/play/2296716506  Fresh Poultry Poultry processing is more mechanical than large animal processing Birds are attached to a conveyor system that slaughters and eviscerates them The metal arm that removes the intestines could easily puncture them, leading to carcass contamination Includes additional steps of scalding (to loosen feathers) and an automated “picker” machine to remove feathers  Meat and Poultry Spoilage Microbiota reflects the potential sources of contamination Mould contamination is ubiquitous, but usually don’t grow on meats stored under 5°C – E.g. Penicillium causes green patches, Mucor causes “whiskers”, and Cladosporium causes “black spot” on whole beef Most ubiquitous yeasts include Candida and Rhodotorula Fungi are less important in poultry and ground beef spoilage Gram-negative bacteria are predominant, including: – Acinetobacter, Aeromonas, Moraxella, Pseudomonas Gram-positive bacteria can also spoil meats, including lactobacilli and enterococci  Video: Interventions During Meat Processing https://www.youtube.com/watch?v=tbyYW4Y jUEg  Spoilage Indicators Off odours Usually the first sign of spoilage Detectable when counts reach log 7.0 – 7.5/cm2 Due to chemicals such as hydrogen sulfide and ammonia from breakdown of amino acids Surface slime Slime is detectable when counts reach log 7.5 – 8.0/cm2 Poultry and beef cuts (e.g. steaks) tend to undergo primarily surface spoilage, but bacteria eventually penetrate deep tissues and cause spoilage there too Discolouration of meat tissue Due to alteration or destruction of meat pigments, or by-products of microbial growth  Meat Inspection Legislation Slaughter and meat processing facilities are inspected by either federal or provincial inspectors to verify that industry is following processes that result in meat that is safe to eat Under Canadian law, each animal must undergo ante-mortem (before slaughter) screening by trained operators to detect potential illness or injury. CFIA personnel then conduct a detailed assessment of any animal showing evidence of disease. Cattle not meeting animal health requirements are identified, segregated, and excluded from meat production. Animals must be slaughtered at either a provincially or federally registered establishment – Meat must also be processed and inspected in these establishments – Meat that is imported into Canada must be from inspected plants that meet Canadian requirements Approximately 95% of animals slaughtered in Canada are slaughtered in federally registered establishments – Majority of meat processed in Canada is processed in federal establishments  Federal Meat Inspection Key meat inspection roles of the CFIA are specified under the new Safe Food for Canadians Regulations: – Registration, licensing, and inspection of slaughter and meat processing establishments – A designated CFIA official needs to evaluate all food animals within 24 hours before slaughter, to ensure they are fit for slaughter – A CFIA veterinary inspector or designate must also conduct a post-mortem inspection of carcasses – For processing plants, number of inspection hours/year are determined based on activities, meat and plant characteristics, and inspection records – Evaluation of compliance with the mandatory Preventive Control Program – Monitoring of product labelling and traceability compliance – Producers of ground beef must have sampling/testing plan for E. coli O157  Federal Meat Inspection A licence holder or CFIA inspector will apply the “inspection legend” to a meat carcass or edible meat product – For carcasses, must be stamped directly or applied on a label after post-mortem examination – The legend is mandatory for products that are traded inter-provincially or exported Beef carcasses must be graded by a certified grader according to the Beef, Bison and Veal Carcass Grade Requirements, prepared by the Canadian Beef Grading Agency – Requirements allow for 13 grades of beef, from Canada Prime to E – Grading of poultry is optional  Beef Grading Grading is mainly based on physical characteristics of the animal and amount of fat cover Grading is intended to place carcasses into uniform groups of similar quality, yield, and value, in order to facilitate marketing and production decisions Grading stamp colour depends on the grade: A = red B = blue D = brown  Frozen Raw Breaded Chicken Includes products such as nuggets, burgers, and strips – Have caused numerous food-borne outbreaks in recent years as they appear “ready to eat” but are a raw product – Microwave cooking is not suitable due to uneven heating The CFIA now requires industry to implement one of the following processing control measures to reduce Salmonella to below detectable levels in these products: – 7-log reduction cook process – Testing program to confirm raw chicken mixture or final product is free from Salmonella – Other validated process(es) to achieve 2-log reduction with Salmonella testing program for raw chicken mixture  Provincial Meat Inspection OMAFRA provides licensing and inspection of animals, meat, and facilities at all provincial abattoirs and processing plants licensed under the Food Safety and Quality Act, 2001 (Ontario Regulation 31/05) Provincial plants are smaller and often service local areas or specialty markets Inspection activities similar to CFIA, but more feasible and applicable for smaller plants Ontario Regulation 31/05 – sections 111-113 Provides guidance for provincial inspection stamps Every edible carcass or part must be stamped, breast tagged (poultry/rabbit), labeled on wrap, or sealed with tamper proof tape (for bulk containers) http://www.omafra.gov.on.ca/english/food/inspection/meatinsp/licenced_operators_list.htm  Provincial Meat Inspection Trained and certified meat inspectors are present anytime slaughter is taking place at a provincially licensed abattoir (slaughterhouse) Also inspect premises, operational practices, and product labelling Inspections are conducted at least once/6 weeks for processing plants (could be as often as once/week for high risk ones) Annual audits are conducted to verify compliance with food safety requirements outlined in the Meat Regulation Audit results are rated as “pass”, “conditional pass”, or “fail” An exit meeting is then held with the plant management, who are provided with a summary of observations and highlighted deficiencies OMAFRA staff follow a progressive compliance protocol for those who are not in compliance  Provincial Meat Inspection OMAFRA licenses are not required for meat processing establishments that: Are restaurants, caterers, and facilities where the majority (>50%) of the business is food service (e.g. preparing and serving meals) Are not food service premises but only prepare sandwiches, pizzas, bouillon, edible oil or fat, products containing