Unit 5b. Cleaning and Sanitation

Sanitation comes from the Latin word “Sanitas” which means health. So for us, in food processing sanitation is creating the environment needed to produce foods that are healthy in the sense that they are not dangerous to consumers.

Despite what many people think, sanitation is much more than using good cleaners or looking at shiny kitchens. Proper Sanitation requires a series of considerations that work together to achieve the goal. In order to sanitize any surface or tool, cleaning must precede. That is why in most literature you will find the terms cleaning and sanitation together. But if we mention sanitation, please remember that if not properly cleaned it cannot be properly sanitized.

Plant Design

Proper sanitation starts with proper plant design. When starting a cheese making business owners must have sanitation as priority one, even before visiting potential sites for their facility. Some questions you might need to ask while choosing any potential facility site:

• Are floors slopped properly, finished without cracks or wholes? Are drains sufficient, well designed?
• Are walls and ceilings smooth, cleanable? Are there hard-to-clean spots?
• Are the premises easy to clean? Do they prevent the entrance of pests? Are they far from potential contaminants e.g. far from a barn, a chemical storage facility?

Equipment design, geometry and position must prevent cross contamination, allow for proper cleaning and sanitation. Before buying any equipment, ask the supplier to provide details on sanitary design.

Cleaning and sanitation chemicals:​

Cleaners and sanitizers are chemicals that allow soils (dirt) to be removed (cleaners) and microbes to be eliminated or reduced substantially (sanitizers). For them to perform properly these chemicals need to be used:

• For a proper amount of time​
• With the proper action (scrubbing, turbulent flow, speed, etc)
• At the exact recommended concentration​
• With the recommended temperature​
• Dissolved in water with adequate characteristics (hardness, microbial loads, etc)​
• By trained individual​s
• Depending on the nature of soil​; what are you trying to eliminate fat, calcium build up, etc?
• According to surface​ characteristics; are you trying to clean a plastic jug, a copper tank,  a stainless steel pipe? Some surfaces are more porous than others and are much harder to sanitize.

Wood in the cheese industry

Wood vats, hoops and shelves are used in some countries to manufacture certain types of cheese; this is to take advantage of certain wood properties such as moisture exchange with the cheese and the environment, transmission of some antimicrobial substances (some types of wood) and accumulation of technological flora on the surface. But remember, if wood can contribute good microflora it can contribute to pathogen contamination too. Proper cleaning of wood material must be followed by prolonged contact (more than 20 minutes) at high temperatures (>70°C). In Canada, the use of wood in dairy facilities is not permitted unless it is used as ripening  hoops or shelves for bacterial surface (washed rinds) ripened cheese.

Organizational​ controls

Cleaning and sanitation must respond to a proper designed plan. This plan is based on Good manufacturing practices (GMPs)​, well defined and written in Standard Operating Procedures (SOPs)​ and controlled by a proper HACCP​  plan (Hazard Analysis and Critical Control Points). Only properly trained personnel can create and implement this plan. There are plenty of training opportunities for owners and employees so they can gain the skills to implement a cleaning and sanitation plan. Help can come from government and non-government agencies, universities and colleges, training agencies, suppliers, etc. We will discuss this in much more detail in the  course Cheese Safety and Quality Assurance.

Process Controls

 Cleaning and Sanitation requirements are specific for each operation. The chemicals used, the processes selected and all controls will depend on:

• The quantity and type of soil​, which is not the same for butter versus processed cheese versus Panela cheese.
• Age of soil​; Did  you keep the curd in the cheese vats for several hours (for example in Cheddar making) before cleaning it?
• Temperature profile​ during processing; for example while making Ricotta we heat up to 95°C, while making feta only requires warming to 30°C.
  

  

• Degree of automation​; Different equipment requires different techniques for cleaning. For example, an open cheese vat requires manual cleaning with the help of tools and chemicals. Small and removable parts are cleaned by COP (Clean out of Place).
  A COP system, consists of one or more rectangular tanks that use high pressure, hot water and chemicals to clean items that cannot be adequately cleaned in place, such as  certain valves, external surfaces of hoses, cheese hoops, clamps, fittings, filling nozzles, trays, knives, etc.

At the same time, an enclosed system such as a pasteurizer or a milk tank can be cleaned without the need of complete disassembly. That can only be achieved with proper Cleaning in Place (CIP).

Environmental

Cleaning and sanitation involves not only proper sanitation of equipment and tools. Pathogens and spoilage microbes can survive anywhere: walls, floors, hanging pipes, vents, drains, refrigeration equipment, shelves and so on. From there they can contaminate cheese by many means. Therefore, a proper cleaning and sanitation program must include a comprehensive sanitation plan with SOPs for cleaning and sanitation of all equipment, environment and tools. The sanitation plan must include a sanitation schedule that secures frequent cleaning of the different components depending on their different needs; for example equipment and floors are cleaned after each use while ceilings are cleaned with less frequency. Special attention must be paid to avoid cross-contamination, for example, cleaning of floors with high pressure water produces water splashing that can contaminate equipment. Hard to clean surfaces such as drains, vents and tile grout require special attention and are frequent sources of pathogenic bacteria such as Listeria monocytogenes.

Soils

While cleaners and sanitizers are two different kind of products, some chemicals such as chlorinated detergents might act as cleaners and sanitizers in one-step. Nevertheless, remember, nothing is sanitized if it has not first been properly cleaned.

Typical food processing facilities are soiled by the main food components –no surprises here-. A butter manufacturer will have to deal with a lot of fat while a cheese manufacturer will deal with lots of proteins and fat to a lesser extent.

Typical Soils found in food plants. Table courtesy of Joe Myatt, Diversey.

As shown in the table, fat residues can be eliminated by proper use of hot alkaline wash; fat is usually easier to remove at warm temperatures because it melts. Protein soils can be managed by proper use of chlorinated alkaline detergents. Protein strongly stuck to surfaces because of heating or drying (such as cheese vats that are not rinsed immediately after processing) requires longer periods and high temperature exposure to alkaline detergents. Rinsing before food residues dry on the surfaces is the easiest way to prevent hard to remove soils.

Milk is rich in Calcium and Magnesium, and tanks and vats might form mineral films (sometimes called milk stone) that are detrimental to many aspects of food safety. Frequent acid washes can prevent formation of these films. This is specially important in milk receiving tanks and pasteurization equipment.

Please note that many cleaners contain chlorine, which is an oxidizing sanitizer as well as Iodine, Mixed Halogens and Peracetic Acid. Non-oxidizing sanitizers include Acid Anionics and Quats. Remember, the objective of a sanitizer is to control or eliminate microbes from surfaces. Milk has good and bad microbes. We deliberately add microbes into milk in the manufacture of cheese, as primary or secondary cultures. The point here is that we need to choose and use sanitizers in a way that does not interfere with cultures.

For example, improper use of chlorine sanitizers in the containers used to keep or develop bulk cultures might decrease or inhibit culture activity. In addition, rennet is very sensible to Chlorine. Therefore, using containers washed with chlorine detergents or sanitizers to measure or mix rennet might decrease its activity. While chlorine cleaners are widely used in the food industry, we prefer to use Iodine products as sanitizers since they don’t interfere with culture or rennet activity if used as recommended.

How do we know that proper cleaning and sanitation has been achieved?

We will discuss Cheese safety and sanitation in a future course, but if you are looking for more information on this topic in the short term, the American Cheese Society has an excellent resource called the Safe Cheese Making Hub (https://guides.cheesesociety.org/safecheesemakinghub).