The Specialist Cheesemakers Code of Best Practice

Milk production

INTRODUCTION

ANIMAL HEALTH AND WELFARE

UDDER INFECTIONS

TEAT INFECTIONS

MASTITIS DISEASE CONTROL

TRADITIONAL MILKING METHODS

HAZARDS IN THE FARM ENVIRONMENT

EQUIPMENT HAZARDS

WRITTEN CLEANING SCHEDULES

MILK HANDLING

INTRODUCTION

4.1 Good quality milk is essential for good quality cheese. Hence it is imperative that the highest possible standard of hygiene is maintained throughout the production process,from milking to the making, handling, and storage of cheese. This includes hygiene of the premises, equipment, and staff.

ANIMAL HEALTH AND WELFARE

4.2 The welfare of the milking animal, be it cow, ewe, goat, or buffalo is important to ensure the quality of milk used for cheesemaking. The nutrition of the animal, the quality of the pasture on which it grazes, its shelter, and milking procedures all have the potential to affect the quality of the milk.

4.3 It is good practice to keep permanent records relating to each animal giving details of:

• mastitis or any other clinical infections;
• any treatment administered by you or by veterinary surgeons, including details of any drugs used;
• any physical abnormalities detected in the milk at the start of milking;
• results of microbiological analysis of that animal’s milk.

4.4 It is also important to pay close attention to the health of milking animals. Ensure that they are in a good state of health and do not show any sign of infection of the genital tract or udder wounds likely to affect the milk. You should also ensure that as far as possible the milking animals are kept clear of infections that can be transmitted to humans (zoonotic infections), e.g., salmonellosis. This can be done by adopting careful farm and animal management. This is particularly important where raw milk is to be used for cheesemaking. There is a risk that raw milk could be contaminated by harmful bacteria, and these could be found in any cheese made from it.

4.5 Hazard analysis principles can be used to prevent the build up of localised high levels of harmful bacteria on the farm. The SCA Technical Bulletin No 1 (see Useful Publications for details of this and other useful publications) contains advice on how to achieve this general objective. It contains a table of milk borne zoonotic infections, routes of infection, main symptoms, and species affected. Some of the most common problems and methods of control are discussed below. However, for detailed advice on these issues you should consult your own vet.

UDDER INFECTIONS

4.6 Udder infections can be a source of problems in milk production. You should be aware that:

• undesirable spoilage and harmful micro-organisms will be secreted from an infected udder;
• high total bacterial counts and high somatic cell counts can be due to infected udders, which may or may not be noticeable;
• antibiotics used in the treatment of udder infections may leave residues in milk which will adversely affect the starter culture and therefore the development of acidity, and ultimately the quality of the cheese.

4.7 You can control udder infections by:

• maintaining good health management for all stock on the farm;
• operating a mastitis disease control programme;
• identifying and separating animals suffering from udder disease. Vets should be called when necessary;
• isolating any animal producing abnormal milk and/or receiving any form of medication which can affect the milk, and not using its milk for human consumption;
• using antibiotics according to manufacturers' instructions, and observing correct withdrawal periods.

TEAT INFECTIONS

4.8 Teat infections can also be a source of concern. Remember that:

• micro-organisms are present in the teat canal and teat surfaces even when there is no infection;
• such micro-organisms can reduce milk quality even if they are not a human health hazard;
• foremilk can become contaminated and be the source of infections.

4.9 You can control teat infections by:

• ensuring as far as possible the cleanliness of animals and their housing. A well ventilated building helps to control environmental mastitis;
• preventing udders from becoming soiled. Possible causes are muddy gateways or drinking trough areas, problems in housing systems, etc.;
• effectively cleaning and drying udders and teats before milking;
• removing and hygienically disposing of foremilk to avoid possible contamination. It is good practice to dispose of the foremilk of all species;
• improving mastitis control systems and eliminating potential problems.

MASTITIS DISEASE CONTROL

4.10 The majority of successful control programmes are based on a five point plan. This involves:

• teat management: clean, dry, well ventilated housing combined with adequate teat preparation and post milking teat disinfection;
• identification, treatment, and recording of all clinical mastitis cases;
• treating with antibiotics at drying off;
• culling animals with a history of mastitis;
• using a milking machine which minimises tissue damage and infection transfer.

TRADITIONAL MILKING METHODS

4.11 Achieving good quality milk does not mean that traditional milking methods cannot be used. Traditional methods of farming and milking, such as the use of buckets and hand milking of animals, are acceptable if good standards of hygiene are maintained.

HAZARDS IN THE FARM ENVIRONMENT

4.12 You should be aware of hazards which exist within the farm environment such as:

• other livestock on the farm especially calves pigs, and poultry;
• pests, such as rodents and insects;
• contamination from surrounding areas.

4.13 You can control these hazards by:

• keeping other animals away from milk production, housing, or storage areas;
• proofing against rodents and having a proper pest control programme in place;
• keeping surrounding areas clean.

EQUIPMENT HAZARDS

4.14 Items of equipment such as milking equipment, bulk milk tanks, pipelines, pumps, churns, and vehicles, etc., are potential sources of contamination. Hazards may arise from:

• inadequate or ineffective cleaning and disinfection;
• poorly maintained equipment;
• the use of incorrect equipment, or equipment not used for the purpose for which it was designed.

4.15 You can control these problems by:

• ensuring regular maintenance of equipment in accordance with manufacturers' instructions;
• preparing and following a written cleaning schedule for all equipment and surfaces (see 4.17 below);
• cleaning using the appropriate detergent or disinfectant designed for that specific purpose and safe for use on food contact surfaces and equipment;
• making sure the detergent is used at the correct strength (it may leave residues if too strong) and temperature, and for the correct contact time according to manufacturers' instructions;
• ensuring that all milk residues are removed from surfaces, etc., immediately after milking;
• checking visible cleanliness of all items of equipment before use, especially milk contact surfaces;
• cleaning dirt, dung, and splashes from exterior surfaces daily;
• checking bacterial content of milk (this will provide test results in retrospect, but will help demonstrate due diligence);
• disinfecting the equipment immediately after cleaning. Equipment which is open and likely to be contaminated should be recleaned and disinfected before use, whereas tanks and pipes, for example, could be cleaned and disinfected after use;
• using equipment only for the purpose for which it was designed.

4.16 Disinfection of clean surfaces can be by either:

• using a steaming stool for disinfection purposes - continue steaming for at least 2 minutes;
• using a steam chest - continue steaming for at least 10 minutes after the temperature of the condensate reaches 96^oC. This is the recommendation in the British Standards Institution Code of Practice 5305 1984: Cleaning and Disinfecting of Plant and Equipment Used in the Dairy Industry. Manufacturers’ instructions for individual pieces of equipment may vary. It is good practice to check sterility by means of swab testing on a regular basis;
• steaming large storage tanks and other vessels - continue for at least 10 minutes after the temperature of the condensate reaches 85^oC;
• circulating or immersing the equipment in hot water at a temperature of 85^oC for at least 10 minutes;
• using a chemical disinfectant, e.g., hypochlorite or iodophor, following the manufacturer’s instructions regarding concentration, contact time and temperature of use.

WRITTEN CLEANING SCHEDULES

4.17 Proper cleaning plays a vital role in food safety. Written cleaning schedules are recommended. Two examples can be found at Annex B. A cleaning schedule should indicate at least:

• the task to be carried out;
• the equipment, materials and cleaning agents required;
• health and safety precautions to be observed;
• the method to be used for the cleaning task;
• the standard and quality of cleaning to be achieved; and
• the frequency of carrying out the task.

MILK HANDLING

4.18 For the best quality cheese, the milk should be used as soon as possible after milking. Milk may be passed direct from the milking area into the cheesemaking room without any form of cooling if the milk is to be immediately used for manufacture. In such cases, the milk must be used as soon as possible.

4.19 Where milk is to be refrigerated before cheesemaking, it must be chilled and stored at a temperature not exceeding 6^oC. At this temperature the milk must be used within 36 hours. However, if the milk is kept at or below 4^oC, the time limit is extended to 48 hours. Milk from ewes, goats, and buffaloes may be stored at a temperature not exceeding 6^oC for up to 72 hours before use. It is best practice to store all milk below 4^oC and use within 36 hours of production. Where bulking up small quantities of milk, which may take up to 36 hours, a milk holding temperature of 2^oC or below is recommended.

4.20 Milk may also be frozen in small quantities for use at a later date. It is recommended that the freezing process begin within 1 hour of milking. The SCA recommended temperature for storing frozen milk is minus 18^oC or lower for a maximum of 6 months. Frozen milk should be adequately thawed at below 4^oC in a refrigerator before use, as this reduces the risk of the multiplication of harmful bacteria. The SCA does not recommend freezing milk in large volume units, as the long thawing period necessary means that there is a risk of harmful bacteria multiplying in the milk.

4.21 Poor handling of the milk may result in hazards occurring. You should be aware that:

• harmful bacteria have the potential to multiply within the milk, especially when that milk has not been cooled before use;
• harmful bacteria may multiply during holding, transport, or storage;
• although cooling inhibits the growth of most micro-organisms, some will multiply over a wide range of temperatures, e.g., Listeria monocytogenes will multiply in the range between 0 to 42^oC although growth is extremely slow below 5^oC.

4.22 You can control such hazards by:

• cooling milk as quickly as possible to less than 6^oC if the milk is not to be immediately used for cheese manufacture;
• storing milk in a cool and protected environment to minimise the growth of undesirable bacteria and prevent the risk of contamination.

4.23 To avoid any problems arising from antibiotics or pesticide residues:

• observe the withdrawal periods for any products used on your own livestock;
• when buying in milk, ensure that wherever possible the contract or conditions of supply state that no pesticides or other residues in excess of the permitted tolerance limits are present. Test at appropriate frequency to ensure compliance.

Specialist Cheesemakers Association    17 Clerkenwell Green    London EC1R 0DP

Tel: 020 7253 2114    Fax: 020 7608 1645    Email: info@specialistcheesemakers.co.uk