WINERY SANITATION – BEST PRACTICES

WINERY SANITATION –BEST PRACTICES K.C. Fugelsang, Professor Emeritus of Enology, California State University, Fresno

WINERY SANITATION INTRODUCTORY REMARKS: • Microorganisms arriving on fruit, and/or already present in the winery can not only survive, but, as conditions permit, proliferate during the winemaking process. • Once established, undetected/uncontrolled population `blooms' can pose a significant threat to wine quality. • Thus, proactive control becomes the cornerstone in minimizing the risk of spoilage and the single most important control point is sanitation. • As with any processing operation, the winery should develop site-specific Standard Operating Procedures (SOP) for sanitation. • SOPs should include specific protocols/procedures as well as schedules that document implementation. • These records become part of the overall Quality Points Program.

WINERY SANITATION DEFINITIONS: • Sanitation: reduction of Viable Cell Number (VCN) to some pre-determined low number (may/may not = 0 CFU/mL). • May be estimated by sampling or subjective means (visual, tactile and/or odor). • Generally a pre-bottling goal. • Sterilization: reduction of VCN to 0 CFU/mL. • Winery sterilization will probably not kill mold spores or bacterial endospores. • Decision as to which goal is required depends upon stage in processing and inherent wine stability. • Many consider the concepts to be synonymous. • Sanitation should be considered as a proactive program: the goal is to minimize uncontrolled growth early in the process thus reducing “pass-through” threats during later stages of processing.

WINERY SANITATION • Considerations for Minimizing “Pass-Through” Contribution: • Adherence to grape quality standards in terms of microbial decomposition. • Sanitation of harvest equipment and containers • Reduce travel time and temperature (evening/early morning harvest) • Crush pad sanitation: reduce accumulations of organics (localized population blooms). • Regularly sanitize primary processing equipment • Properly conducted, the sanitation program limits build–up of mineral and organic debris (grape “bloom,” tartrates, biofilms, etc.) which serve as reservoirs for microbial proliferation and reinfection and, potentially, biofilm formation. • Biofilms: impervious polysaccharide layer or film produced by microbes in >C, N environs. • Sanitation cycles using caustics (75°C/167°F for 30 minutes), followed by citric acid rinse have proven successful in removing biofilms (Parkar, et al., 2004).

WINERY SANITATION HEALTH AND SAFETY ISSUES: • A two-fold concern: (1) Chemical cleaners/sanitizers/sterilants are typically strong oxidants, caustics, and/or acidic chemicals and (2) the physical environment and processes: high pressure hot water and/or steam, and slippery floors. • Requires personal protective equipment (PPE) including gloves, goggles, appropriate footwear, and waterproof aprons. • Given the slippery properties of detergents when discharged on floors, boots with non–skid soles should be used. • Employee training should emphasize the importance of reading product labels and understanding each chemical’s advantages/ limitations and safety concerns prior to use. • Material Safety Data Sheets (MSDS) sheets containing the necessary health and safety information for employees working with winery chemicals should be readily available (24/7) and clearly identifiable in prominently displayed binders, etc. • Available from supplier or, if lost, on-line.

WINERY SANITATION An effective sanitation program consists of at least three and, potentially, four levels of effort and vigilance. The first step is preparation of the surface to be sanitized/sterilized. I. PRELIMINARY CLEANING: • In any sanitation process, the first step is to remove as much of the first–level or visible debris as possible. • Accomplished either manually or by mechanical cleaning systems such as spray balls or tank and barrel washers. • High pressure water (600 to 1,200 lb/in2) without added chemicals can often readily remove organics and build–up at a fraction of the cost associated with the use of an equivalent amount of detergent or sanitizer needed to accomplish the same goal. • Most effective when the spray is directed at an angle to the surface being cleaned. • Using warm water (38oC/100oF to 43oC/109oF) in a high pressure delivery system further improves cleaning operation while decreasing both the amount of water used and time required for cleaning.

WINERY SANITATION • Although tempting, application of heat to organic materials adhering on a surface debris should be avoided. • The practice may serve to “cook on” the debris, thereby requiring greater effort and costs to effect removal. • Where stains/bloom remain, it may be necessary for workers to enter the tank. • Fermentors and/or storage tanks are regarded as “confined spaces,” and as such, special health and safety regulations apply. • These include preliminary forced-air ventilation of the tank to reduce carbon dioxide levels followed by verification that safe levels have been reached. • Carbon dioxide and oxygen are easily measured by use of readily available and moderately-priced meters and probes. • Current National Institute for Occupational Safety and Health (NIOSH) definitions of “safe” for oxygen is >19.5% (v/v) whereas for carbon dioxide the “Permissible Exposure Level (PEL) is <5,000 ppm (on-line: 2008).

WINERY SANITATION • Once cleared for entry, employee(s) must be equipped with harnesses and tethered to the outside through side/bottom manhole where at least one worker remains on-station during the entire operation. • To prevent compromising the integrity of the protective oxide coating on stainless steel, only soft–bristle brushes should be used in cases where scrubbing is required. • Once stainless steel surfaces are scratched, these rapidly become susceptible to oxidation and corrosion. • As such, fiber or metal “scratch” pads or brushes should never be used for removal of tenacious deposits. Water Chemistry: Basic components of the sanitation program includes water quality (hardness, odor, particulates) and availability. • Hardness: calcium, magnesium, and other alkali metals interfere with the effectiveness of detergents, particularly bicarbonates, and contributes to the formation of precipitates or “scale” on equipment.

WINERY SANITATION • Besides diminishing the appearance of equipment or surface, these precipitates serve as sites for accumulation of organic debris and microorganisms, making subsequent sanitation efforts difficult. • Perhaps, the least expensive method to alleviate this problem is through installation of a water softener. • Water should be analyzed two to four times a year depending on the source (well or city). • Routine testing includes pH, alkalinity, calcium hardness, iron, silica, total dissolved solids, and a standard plate count for microorganisms. II. DETERGENT(S) AND DETERGENT FORMULATIONS: • Once visible debris and film has been removed, detergents/cleaners are incorporated into the process to solubilize any remaining deposits. Each detergent has unique properties of action for the most effective application. • Dry chemicals should always be added to cold water rather than to hot.

WINERY SANITATION • Generally, increasing the concentration beyond recommended levels provides little additional benefit and is not cost effective. • Typical components of a detergent formulation: • alkali (“active ingredient”) • sequestering agent(s) • surfactants • Strong alkali's or `caustics,' such as NaOH (caustic soda or lye) or KOH (caustic potash) are most commonly used at this stage. • Although concentrations and temperatures vary, a typical protocol calls for 1-2% (w/v) caustic dissolved in warm (approx 38oC/100oF) water followed by heating the solution to 75oC/167oF to 80oC/176oF and application to contact surface for 15-20 minutes. • Both caustics have >detergent properties and >antimicrobial activity (viable cells as well as spores and bacteriophage) as well. • May also serve as sterilizing agents as well. • However, strong alkalis are corrosive towards mild steel and, in excess, stainless steel as well.

WINERY SANITATION • Silicates: Although less caustic than NaOH, sodium ortho– and meta–silicates (Na2SiO3) silicates possess better detergent properties, and are less corrosive towards equipment than caustics. • In the case of low organic load situations, mild alkalies such as sodium carbonate (soda ash) or trisodium phosphate (TSP) find application. • However, regular use of sodium carbonate may contribute to precipitate (“scale”) formation when used in hard water. • TSP may be corrosive upon repeated applications on mild steel and is degraded by hot water. Regular use leads to elevated phosphate level in discharge water may contribute to algal blooms (Butzke, 2010). • In many wineries, the caustic wash cycle followed by a thorough citric acid-water rinse, fulfills the sanitation requirements for fermentorsand wine storage tanks. • Chelating or Sequestering Agents: • Can also be added to detergent formulation at extra cost for removal of Ca++ and Mg+ (components of precipitates).

WINERY SANITATION • Trisodiumphosphate (TSP) at 4 g/L, or polyphosphates (sodium hexametaphosphate or CalgonTM and/or sodium tetraphosphate -QuadrofosTM). • EDTA - more expensive, less degradation. • Phosphoric acid (0.5% v/v). Dissolves scale and is relatively non-corrosive and compatible with nonionic wetting agents. Wetting Agents (Surfactants): • Non-corrosive compounds that “break-down” organic deposits by interspersing water. • Typically, 13-15 carbon chains - hydrophobic end with affinity for oils and a carboxyl group (COO-) hydrophilic end with affinity for water. • Align themselves at the interface between water and organic layers. • Very soluble in cold water and not impacted by hot water. • Detergent formulations typically have around 0.15% wetting agents • Many are stable in both acid and alkaline solutions.

WINERY SANITATION • Several of the noted components may be present pre-mixed and ready-for-use in a single detergent formulation. • Referred to as “built detergents” or “built cleaners” • Depending upon composition, may achieve multiple cleaning goals in a single application. • Alternatively, formulations can be prepared at the winery using individual chemicals and ingredients. • When formulating detergent mixes, the staff should consult specific suppliers for information related to proper use of chemicals. III. SANITIZERS • Depending upon stage in processing and the need for biological stability, it may be necessary to follow-up using of one, or more, sanitizing/sterilizing agents. • Regardless of application, sanitizing agents should be used once the surface has been thoroughly cleaned.

WINERY SANITATION • Selection of sanitizing agents includes: • Halogens (iodine and, historically, chorine-based compounds) • Quaternary ammonium salts, • Peroxides, • Hot water/steam, • Ozone. • Depending upon application (eg., winery hose), acidulated sulfur dioxide is also widely used. Halogens (Chlorine and Iodine): • Chlorine and chlorine-based sanitizers: HISTORICAL PERSPECTIVE!! • Use of chlorine or chlorine-containing detergents/sanitizing agents may increase the potential for formation of environmental TCA. • NOT RECOMMENDED FOR ANY USE IN THE WINERY ENVIRONMENT. • We do not allow our janitorial staff to use chlorine or chlorine-containing product.

WINERY SANITATION • Iodine-Based Sanitizers: formulations of iodine + nonionic wetting agents are called iodophors. • Iodophores are not rapidly degraded by organics and relatively nonirritating. • Maximum effectiveness at pH 4-5 (concentration of I2 is maximum) • Includes phosphoric acid to ensure low pH. • Concerns with the use of iodine-based sanitizers: • Volatilize at >120oF • may stain PVC and hose. • foams excessively. Quaternary Ammonium Compounds (QUATS): • Exist as cationic surface-active agents (surfactants), of the general structure NR4+ : • Nitrogen is covalently bonded to four alkyl or aromatic groups.

WINERY SANITATION • Unlike other ionic species, QUATS are permanently charged and, thus, independent of the pH of solution. • The antimicrobial properties of QUATS reside in their strong affinity for negatively-charged surfaces, such as bacterial cell surfaces, where they function by disrupting cell membrane operation. • In addition to activity and stability over a broad pH range, activity is not compromised by hard water. • QUATS are often employed for the control of mold on the outside surfaces of tanks as well as winery walls, floors and in drains. Here, the formulation is sprayed onto the surface and left without rinsing. • Most lab bench-top sterilants are QUATS. Other Agents: Acidulated Sulfur Dioxide: • Acidulated SO2 may be used as an effective sanitizing agent especially for hoses and other equipment. • Because the antimicrobial activity of SO2 is pH dependent, the agent (100 mg/L SO2 or 200 mg/L potassium metabisulfite) is usually made up in acidulated solution by inclusion of 3-5 g/L citric acid.

WINERY SANITATION • Caution: Strong SO2 solutions irreversibly damage silicon, rubber and plastic parts such as bungs and press membranes/bladders (Butzke, 2010). Continual exposure may lead to corrosion of 304-grade stainless steel surfaces. • Due to volatility and corrosive properties, SO2 solutions should only be used in a well ventilated area away from metal surfaces due to volatility and corrosive properties. • Employees should be cautioned to avoid direct contact or inhalation of SO2. • Although wineries commonly prepare this sanitizer in acidulated, hot water (60°C/140°F), this practice serves to increase the volatility as well as increased safety risks. When not in use, SO2 solutions should be sealed to minimize volatilization. Peroxides: Also known as “proxy” compounds, the group consists of strong oxidizing agents including hydrogen peroxide and peroxy-acetic acidic having at least one pair of highly reactive covalently bonded oxygen atoms (–O–O–).

WINERY SANITATION Hydrogen peroxide (H2O2): highly reactive oxidant that breaks down to generate toxic singlet or superoxide (O2–) oxygen. • Commercially available in concentrations ranging from 3-30% v/v. • The former can be purchased at pharmacies as a topical antiseptic for treatment of abrasions and is used in the lab for microbiological testing. • The more highly concentrated form, must be obtained from chemical supply companies. • At concentrations >5% v/v, hydrogen peroxide becomes a strong irritant that can cause burns and blisters on exposed skin. Staff working with the agent should be trained and cautioned in its use. • Unless stored in a sealed container, H2O2 rapidly breaks down with time. Sodium percarbonate(2 Na2CO3•3 H2O2) : stabilized powder containing hydrogen peroxide. • Widely used as the active component in laundry detergent and all fabric bleach as well as denture cleaners, pulp and paper bleaching and wine barrel treatment.

WINERY SANITATION • The highly reactive product has an available [O2] equivalent to 27.5% H2O2 and, like peroxide, breaks down to the reactive form, oxygen as well as water and sodium carbonate upon full reaction. • Sodium percarbonate is sold under the trade name Proxycarb™ and is widely used to treat barrels believed to be contaminated with spoilage microorganisms and/or to neutralize offensive odors that may be present. • 100% kill is unlikely given the porous nature of wood. Peroxyacetic acid (PAA): sometimes referred to as “peracetic acid,” is also a highly reactive oxidant with antimicrobial properties similar to hydrogen peroxide. • All commercial PAA products contain an equilibrium of PAA, hydrogen peroxide, acetic acid, and water. • As a sanitizer and sterilant, PAA has several desirable characteristics not found with H2O2 including: • Better stability at application concentrations (100 to 200 mg/L), • Improved compatibility with hard water, and reduced foaming. • .

WINERY SANITATION • PAA exhibits reduced corrosive properties and is biodegradable. • Like hydrogen peroxide, concentrated PAA (40% w/v) is a highly toxic oxidant. • In diluted form, its best applications include barrel and bottling line sanitation and sterilization. Physical Sterilants: Hot water (>82oC/180oF) and steam • Historically, considered as the “ideal” sterilant. • In addition to their universally lethal impact on microbes, hot water/steam are noncorrosive and, properly used, leave no residue. • Major concerns with the use of either/both include costs associated with generation and delivery of sufficient volumes to meet the time and temperature requirements for sterilization. • Further, regular use of either/both may degrade gaskets more rapidly than other agents.

WINERY SANITATION • The most frequent application for hot water/steam is bottling line sterilization. Hot water sterilization requires temperatures greater than 82oC/180oF for no less than 20 minutes as monitored at the point most distal to the steam source (i.e., the end of the line, fill spouts, etc.). • The sterilization cycle begins when the target temperature is reached. • Where “hard” water is used, salt precipitates (scale) may be a concern during rinse and cool-down cycle. Ozone: Ozone (O3) is one of the most potent sanitizers available and, thus, is finding increased use as a replacement for other sanitizers in the food and wine industry. • As an oxidant, ozone’s properties reside in its inherent instability and rapid release of oxygen in transition from O3 to O2 upon contact with soluble or particulate oxidizable substrates. • In that decomposition is accelerated by heat, the gas is typically used in conjunction with cold water applications. • Decomposition a function of organic load + temperature.

WINERY SANITATION • Whereas early uses of ozone centered on cold water CIP systems such as bottling lines and heat exchangers etc., many wineries are now using it for domestic and wastewater treatment as well as in barrel washing. • Because O3 rapidly degrades to O2, it cannot be stored and must be generated on demand. • Long-term effect on equipment (particularly soft parts such as gaskets) is unclear. • Very low solubility ->out gassing (health and safety issue). • Ozone is a strong irritant and uncontrolled exposure may result in inflammation of eyes, nose throat and lungs. • The legal maximum concentration for an 8–hour continuous exposure is 0.1 mg/L whereas the limit for short–term exposure is 0.2 mg/L for 10 minutes (Khadre et al., 2001). • Staff should be well trained and use proper ozone safety monitors.

WINERY SANITATION Ultraviolet light (UVL)/Photon sterilization technology (PST): • Although UVL is directly effective against microbes, it has very low penetrative capabilities and even a thin film of water will serve as an effective barrier between radiation and microbes. • Photon sterilization technology (PST) systems work by generating photons from UV rays created by a series of fluorescent tubes. • Effective against both airborne microbes and those present on contact surfaces. • Although relatively new to the wine industry, such systems have been used in the food industry for sometime. Dry Ice Blasting. The Rajeunir (Fr. "rejuvenate") system uses dry ice to effect removal of surface contaminants (tartrates, etc) in barrels without significant (1.25 mm) abrasion . Ultrasound/HPU: Electrical energy can be converted to lethal ultrasonic sound waves. • HPU generates a stream of “micro-bubbles” that, upon cavitation, generate high energy shock waves that impact/disrupt particulates on surfaces.

WINERY SANITATION • HPU is used for both cleaning and sanitizing, especially, barrels. • Advantages of HPU systems include reduced energy costs as well as reduced chemical input and low volume water usage. Biofilms: While cleaning and sanitation processes will significantly lower microbial populations, there may be survivors depending on the degree of debris buildup and the effort expended during routine sanitation operations. • Growth of survivors may form a colony of cells known as a “biofilm.” • Biofilms exhibit increased resistance to antimicrobials and are difficult to remove. • Eventually, these colonies become large enough to trap soil, debris, nutrients, and other microorganisms • Biofilm formation by O. oenias well as Brettanomycesbruxellensishas been observed on stainless steel. • A commonly used procedure for removing biofilms in clean–in–place systems utilizes a caustic wash (167°F for 30 minutes) followed by acid (167°F for 30 minutes).

WINERY SANITATION IV. FINISHING OPERATIONS: • Once the cleaning/sanitation cycle is completed, contact surfaces should be thoroughly rinsed, using either hot or cold water, to remove residual chemicals. • Citric acid is often incorporated into the rinse to neutralize alkaline detergent residues. V. SANITATION MONITORING: • Effectiveness of the sanitation program is, necessarily, an ongoing concern. • Efforts to detect poorly cleaned and sanitized surfaces may range from simple subjective sensory evaluation (i.e., absence of odor and stains) to the use of surface swabs and enzymatic assays. • Sampling sites should be selected to include all points that may escape treatment and, thus, harbor microorganisms. • Important among these are contact surfaces of processing equipment as well as the interior of pipelines, conveyors and tanks.

WINERY SANITATION • Other areas subject to indirect contamination should also be reviewed: • These include condensate from ceilings or equipment, aerosols, and lubricants. • Testing protocol include conventional direct contact testing utilizing swab tests (4” x 4” area) and agar (Rodac) plates as well as bioluminescence methods using luciferin-luciferase (“fire-fly”) enzyme. • Enzymatic methods monitor environmental ATP and assumes a direct relationship to living cells. • Interferences and problems with method include the assumption that ATP formation during growth of yeast and bacteria is equivalent. In fact, yeast may produce >100x the amount of ATP produced by bacteria at same stage of growth.

WINERY SANITATION SAFETY ISSUES (SUMMARY): Sanitation typically uses strong agents such as oxidants (peroxides, ozone), caustics (NaOH or KOH), and/or acidic chemicals (phosphoric acid) as well as pressurized hot water and/or steam. • Further, slippery floors resulting from discharge of detergents represent ongoing safety concerns . • Employees regularly in contact with sanitizing chemicals should thoroughly trained (and retrained as necessary) in their safe use. The employee’s “right to know” is a cornerstone of Federal and State health and safety regulations. • Thus, part of any employee training program should include identification of the health and safety information concerns associated with any chemical or operation. • This information is contained in the Material Safety Data Sheets (MSDS) that accompany shipments of chemicals and online. • Must be made available to any employee at any time (24/7) of during the workday.

WINERY SANITATION • To comply with regulations, it is recommended that they be kept alphabetized in clearly identifiable and displayed binders in the work area. Further, workers should be issued (or required to purchase) personal protective equipment (PPE) including water–repellant aprons and boots (non-skid soles) in addition to goggles and appropriate gloves. Fementorsand/or storage tanks are considered as “confined spaces.” • When it is necessary for workers to enter, special health and safety regulations apply. • These include preliminary forced-air ventilation of the tank to reduce carbon dioxide levels followed by verification that have safe levels have been reached. • Current National Institute for Occupational Safety and Health (NIOSH) definitions of “safe” for oxygen is >19.5% (v/v) whereas for carbon dioxide the permissible exposure level (PEL) is <5,000 ppm (on-line: 2008). Carbon dioxide and oxygen are easily measured by use of readily available and moderately-priced meters and probes.

WINERY SANITATION • Once cleared for entry, employee(s) must be equipped with harnesses and tethered to the outside through side/bottom manhole where at least one worker remains on-station during the entire operation. Because of safety concerns, tank placards must include a confined space warning such as that seen in the following figure: Required OSHA Warning Required TTB documentation

WINERY SANITATION TRAINING AND DOCUMENTATION • While winery sanitation programs may vary in terms of both schedules and protocol, it is important to insure that such operations are carried out in a safe and consistent manner. • One way to accomplish this goal is to develop a system of documents that not only defines each step in the process but validates the results as well. • Such operational guides are referred to as Standard Operating Procedures (SOPs) which describe in a concise manner, the site-specific procedure from set-up to clean-up. • In the case of winery sanitation, the SOP defines not only the chemicals, and the concentrations used, but the equipment required and time-frame as well as any follow-up testing required. • Employee training is required by law. This applies not only to the first time a new employee carries out the operation but any supplemental (“tailgates”) or retraining that may be necessary. • The supervisor should always document attendance at such training sessions and rosters should be kept on file for inspection as necessary.

QUESTIONS? CONTACT INFORMATION: K.C. Fugelsang, Department of Viticulture and Enology, C.S.U. Fresno 559.278.2791 kennethf@csufresno.edu

WINERY SANITATION – BEST PRACTICES